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Guérineau NC, Campos P, Le Tissier PR, Hodson DJ, Mollard P. Cell Networks in Endocrine/Neuroendocrine Gland Function. Compr Physiol 2022; 12:3371-3415. [PMID: 35578964 DOI: 10.1002/cphy.c210031] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Reproduction, growth, stress, and metabolism are determined by endocrine/neuroendocrine systems that regulate circulating hormone concentrations. All these systems generate rhythms and changes in hormone pulsatility observed in a variety of pathophysiological states. Thus, the output of endocrine/neuroendocrine systems must be regulated within a narrow window of effective hormone concentrations but must also maintain a capacity for plasticity to respond to changing physiological demands. Remarkably most endocrinologists still have a "textbook" view of endocrine gland organization which has emanated from 20th century histological studies on thin 2D tissue sections. However, 21st -century technological advances, including in-depth 3D imaging of specific cell types have vastly changed our knowledge. We now know that various levels of multicellular organization can be found across different glands, that organizational motifs can vary between species and can be modified to enhance or decrease hormonal release. This article focuses on how the organization of cells regulates hormone output using three endocrine/neuroendocrine glands that present different levels of organization and complexity: the adrenal medulla, with a single neuroendocrine cell type; the anterior pituitary, with multiple intermingled cell types; and the pancreas with multiple intermingled cell types organized into distinct functional units. We give an overview of recent methodologies that allow the study of the different components within endocrine systems, particularly their temporal and spatial relationships. We believe the emerging findings about network organization, and its impact on hormone secretion, are crucial to understanding how homeostatic regulation of endocrine axes is carried out within endocrine organs themselves. © 2022 American Physiological Society. Compr Physiol 12:3371-3415, 2022.
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Affiliation(s)
| | - Pauline Campos
- College of Engineering, Mathematics and Physical Sciences, University of Exeter, Exeter, UK
| | - Paul R Le Tissier
- Centre for Discovery Brain Sciences, University of Edinburgh, Edinburgh, Scotland, UK
| | - David J Hodson
- Institute of Metabolism and Systems Research (IMSR), University of Birmingham, Edgbaston, UK.,Centre for Endocrinology, Diabetes and Metabolism, Birmingham Health Partners, Birmingham, UK.,COMPARE University of Birmingham and University of Nottingham Midlands, UK.,Oxford Centre for Diabetes, Endocrinology and Metabolism (OCDEM), NIHR Oxford Biomedical Research Centre, Churchill Hospital, Radcliffe Department of Medicine, University of Oxford, Oxford, UK
| | - Patrice Mollard
- IGF, University of Montpellier, CNRS, INSERM, Montpellier, France
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Liu PY, Takahashi PY, Yang RJ, Iranmanesh A, Veldhuis JD. Age and time-of-day differences in the hypothalamo-pituitary-testicular, and adrenal, response to total overnight sleep deprivation. Sleep 2021; 43:5717179. [PMID: 31993665 DOI: 10.1093/sleep/zsaa008] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2019] [Revised: 01/08/2020] [Indexed: 11/14/2022] Open
Abstract
STUDY OBJECTIVES In young men, sleep restriction decreases testosterone (Te) and increases afternoon cortisol (F), leading to anabolic-catabolic imbalance, insulin resistance, and other andrological health consequences. Age-related differences in the hypothalamo-pituitary-testicular/adrenal response to sleep restriction could expose older individuals to greater or lesser risk. We aimed to evaluate and compare the 24-h and time-of-day effect of sleep restriction on F, luteinizing hormone (LH), and Te in young and older men. METHODS Thirty-five healthy men, aged 18-30 (n = 17) and 60-80 (n =18) years, underwent overnight sleep deprivation (complete nighttime wakefulness) or nighttime sleep (10 pm to 6 am) with concurrent 10-min blood sampling in a prospectively randomized crossover study. F, LH, and Te secretion were calculated by deconvolution analysis. RESULTS Sleep deprivation had multiple effects on 24-h Te secretion with significant reductions in mean concentrations, basal, total and pulsatile secretion, and pulse frequency (each p < 0.05), in the absence of detectable changes in LH. These effects were most apparent in older men and differed according to age for some parameters: pulsatile Te secretion (p = 0.03) and Te pulse frequency (p = 0.02). Time-of-day analyses revealed that sleep restriction significantly reduced Te in the morning and afternoon, reduced LH in the morning in both age groups, and increased F in the afternoon in older men. CONCLUSIONS These data suggest a time-of-day dependent uncoupling of the regulatory control of the testicular axis and of F secretion. Future studies will need to directly verify these regulatory possibilities specifically and separately in young and older men. CLINICAL TRIAL Not applicable.
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Affiliation(s)
- Peter Y Liu
- Department of Medicine, Division of Endocrinology, Harbor-UCLA Medical Center and Los Angeles Biomedical Research Institute, David Geffen School of Medicine at UCLA, Los Angeles, CA
| | - Paul Y Takahashi
- Department of Primary Care Internal Medicine, Mayo Clinic, Rochester, MN
| | - Rebecca J Yang
- Endocrine Research Unit, Mayo School of Graduate Medical Education, Center for Translational Science Activities, Mayo Clinic, Rochester, MN
| | - Ali Iranmanesh
- Endocrine Service, Salem Veterans Affairs Medical Center, Salem, VA
| | - Johannes D Veldhuis
- Endocrine Research Unit, Mayo School of Graduate Medical Education, Center for Translational Science Activities, Mayo Clinic, Rochester, MN
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Roelfsema F, Yang RJ, Liu PY, Takahashi PY, Veldhuis JD. Feedback on LH in Testosterone-Clamped Men Depends on the Mode of Testosterone Administration and Body Composition. J Endocr Soc 2018; 3:235-249. [PMID: 30623162 PMCID: PMC6320245 DOI: 10.1210/js.2018-00317] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/28/2018] [Accepted: 11/20/2018] [Indexed: 11/19/2022] Open
Abstract
Context Quantitative studies of the short-term feedback of testosterone (T) on luteinizing hormone (LH) secretion in healthy men are relatively rare. Such studies require the shutting down of endogenous T secretion and the imposition of experimentally controlled IV T addback. Objective To evaluate whether pulsatile and continuous T delivery confers equivalent negative feedback on LH secretion. Design This was a placebo-controlled, blinded, and prospectively randomized crossover study comprising 16 healthy men [age range 23 to 54 years and a body mass index (BMI) between 22.3 and 34.2 kg/m2]. Subjects received ketoconazole to block endogenous T secretion and received continuous or 90-minute pulses of IV T addback. Setting The study was performed in a Clinical Translational Research Unit. Interventions Subjects underwent 14 hours of blood sampling at 10-minute intervals, with a bolus IV injection of 33 ng/kg gonadotropin-releasing hormone (GnRH). Main Outcome Measures Log-transformed LH and T concentration ratios before and after GnRH administration. Results Despite higher T concentrations during pulsatile T feedback, LH concentrations and secretion rates, whether driven by endogenous or exogenous GnRH, were similar to those during continuous T infusion, indicating diminished pulsatile T feedback. Feedback correlated negatively with BMI. Under controlled T feedback, basal but not pulsatile LH secretion correlated negatively with CT-estimated visceral fat mass. Conclusion Feedback by pulsatile T delivery has diminished inhibitory strength compared with continuous infusion. Feedback is negatively correlated with BMI.
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Affiliation(s)
- Ferdinand Roelfsema
- Department of Internal Medicine, Section Endocrinology and Metabolism, Leiden University Medical Center, Leiden, Netherlands
| | - Rebecca J Yang
- Endocrine Research Unit, Mayo School of Graduate Medical Education, Center for Translational Science Activities, Mayo Clinic, Rochester, Minnesota
| | - Peter Y Liu
- Endocrine Research Unit, Mayo School of Graduate Medical Education, Center for Translational Science Activities, Mayo Clinic, Rochester, Minnesota.,Division of Endocrinology, Department of Medicine, David Geffen School of Medicine at University of California Los Angeles, Harbor-University of California Los Angeles Medical Center, and Los Angeles Biomedical Research Institute, Los Angeles, California
| | - Paul Y Takahashi
- Department of Primary Care Internal Medicine, Mayo Clinic, Rochester, Minnesota
| | - Johannes D Veldhuis
- Endocrine Research Unit, Mayo School of Graduate Medical Education, Center for Translational Science Activities, Mayo Clinic, Rochester, Minnesota
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Roelfsema F, Yang RJ, Takahashi PY, Erickson D, Bowers CY, Veldhuis JD. Effects of Toremifene, a Selective Estrogen Receptor Modulator, on Spontaneous and Stimulated GH Secretion, IGF-I, and IGF-Binding Proteins in Healthy Elderly Subjects. J Endocr Soc 2017; 2:154-165. [PMID: 29383334 PMCID: PMC5789038 DOI: 10.1210/js.2017-00457] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/22/2017] [Accepted: 12/21/2017] [Indexed: 11/19/2022] Open
Abstract
Context: Estrogens amplify spontaneous and stimulated growth hormone (GH) secretion, whereas they diminish GH-dependent insulin-like growth factor (IGF)-I in a dose-dependent manner. Selective estrogen receptor modulators (SERMs), including tamoxifen and toremifene, are widely adjunctively used in breast and prostate cancer. Although some endocrine effects of tamoxifen are known, few data are available for toremifene. Objective: To explore sex-dependent effects of toremifene on spontaneous 10-hour overnight GH secretion, followed by GH-releasing hormone–ghrelin stimulation. Additionally, effects on IGF-I, its binding proteins, and sex hormone–binding globulin (SHBG) were quantified. Participants and Design: Twenty men and 20 women, within an allowable age range of 50 to 80 years, volunteered for this double-blind, placebo-controlled prospective crossover study. Ten-minute blood sampling was done for 10 hours overnight and then for 2 hours after combined GH-releasing hormone–ghrelin injection. Main Outcome Measures: Pulsatile GH and stimulated GH secretion, and fasting levels of IGF-I, IGF-binding protein (IGFBP)1, IGFBP3, and SHBG. Results: Toremifene did not enhance pulsatile or stimulated GH secretion, but decreased IGF-I by 20% in men and women. IGFBP3 was unchanged, whereas while IGFBP1 and SHBG increased in both sexes to a similar extent. Conclusions: The expected rise in spontaneous and stimulated GH secretion under the diminished negative feedback restraint of powered IGF-I favors a central inhibitory antiestrogenic effect of toremifene. Estrogenic effects of toremifene on the liver were present, as evidenced by increased IGFBP1 and SHBG levels. Men and women responded to this SERM comparably.
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Affiliation(s)
- Ferdinand Roelfsema
- Department of Internal Medicine, Section of Endocrinology and Metabolism, Leiden University Medical Center, 2333 ZA Leiden, Netherlands
| | - Rebecca J Yang
- Endocrine Research Unit, Mayo School of Graduate Medical Education, Center for Translational Science Activities, Mayo Clinic, Rochester, Minnesota 55905
| | - Paul Y Takahashi
- Department of Primary Care Internal Medicine, Mayo Clinic, Rochester, Minnesota 55905
| | - Dana Erickson
- Department of Endocrinology, Mayo Clinic, Rochester, Minnesota 55905
| | - Cyril Y Bowers
- Department of Internal Medicine, Tulane University Health Sciences Center, New Orleans, Louisiana 70112
| | - Johannes D Veldhuis
- Endocrine Research Unit, Mayo School of Graduate Medical Education, Center for Translational Science Activities, Mayo Clinic, Rochester, Minnesota 55905
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Roelfsema F, Boelen A, Kalsbeek A, Fliers E. Regulatory aspects of the human hypothalamus-pituitary-thyroid axis. Best Pract Res Clin Endocrinol Metab 2017; 31:487-503. [PMID: 29223283 DOI: 10.1016/j.beem.2017.09.004] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
Thyroid hormones are essential for growth, differentiation and metabolism during prenatal and postnatal life. The hypothalamus-pituitary-thyroid (HPT)-axis is optimized for these actions. Knowledge of this hormonal axis is derived from decades of experiments in animals and man, and more recently from spontaneous mutations in man and constructed mutations in mice. This review examines the HPT-axis in relation to 24 h TSH profiles in men in various physiological and pathophysiological conditions, including obesity, age, longevity, and primary as well as central hypothyroidism. Hormone rhythms can be analyzed by quantitative methods, e.g. operator-independent deconvolution, approximate entropy and fitting the 24-h component by Cosinor analysis or related procedures. These approaches have identified some of the regulatory components in (patho)physiological conditions.
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Affiliation(s)
- Ferdinand Roelfsema
- Department of Internal Medicine, Section Endocrinology and Metabolic Diseases, Leiden University Medical Center, 2333 ZA Leiden, The Netherlands.
| | - Anita Boelen
- Department of Endocrinology and Metabolism, Academic Medical Centre, University of Amsterdam, 1100 DD Amsterdam, The Netherlands.
| | - Andries Kalsbeek
- Department of Endocrinology and Metabolism, Academic Medical Centre, University of Amsterdam, 1100 DD Amsterdam, The Netherlands; Netherlands Institute for Neuroscience, Hypothalamic Integration Mechanisms, 1105 BA Amsterdam, The Netherlands.
| | - Eric Fliers
- Department of Endocrinology and Metabolism, Academic Medical Centre, University of Amsterdam, 1100 DD Amsterdam, The Netherlands. e,
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Roelfsema F, Aoun P, Takahashi PY, Erickson D, Yang R, Veldhuis JD. Regulation of Pulsatile and Entropic ACTH Secretion Under Fixed Exogenous Secretagogue Clamps. J Clin Endocrinol Metab 2017; 102:2611-2619. [PMID: 28368521 PMCID: PMC5505204 DOI: 10.1210/jc.2017-00115] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/12/2017] [Accepted: 03/22/2017] [Indexed: 11/19/2022]
Abstract
BACKGROUND Adrenocorticotropic hormone (ACTH) secretion is controlled by unobservable hypothalamic corticotropin-releasing hormone (CRH) and arginine vasopressin (AVP) pulses. Clamping exogenous CRH or AVP input could allow indirect quantification of the impact of the endogenous heterotypic hormone. METHODS We conducted a randomized, double-blind, placebo-controlled, crossover study in 28 healthy adults (16 men). Volunteers underwent a sex-steroid clamp and a cortisol clamp. ACTH was measured over 10 hours by 10-minute sampling during each of four randomized intravenous (IV) secretagogue clamps (i.e., continuous IV CRH, AVP, both peptides, or saline). Desensitization was tested by bolus injection of the noninfused peptide. RESULTS Mean ± standard error of the mean 10-hour ACTH concentrations (ng/L) in the sex-combined analysis were: saline, 32 ± 4.6; AVP, 29 ± 4.6; CRH, 67 ± 6.2; and CRH-AVP, 67 ± 8.8 (any CRH vs AVP or saline, P < 0.0001). CRH and AVP increased approximate entropy (relative randomness) of ACTH release (P < 0.0001). Bolus AVP injection after CRH infusion yielded a 2.5-hour ACTH concentration of 46 ± 4.3, exceeding that seen after bolus CRH or saline injection (26 ± 3.3 and 24 ± 3.6, respectively; P = 0.002 and 0.001). Sex hormone clamps did not influence ACTH levels. CONCLUSIONS A CRH, but not AVP, clamp yields sustained pulsatile ACTH secretion with high ACTH secretory-burst mass and randomness. After 10-hour CRH infusion, bolus AVP but not CRH, evoked marked ACTH release, likely caused by heterotypic sensitization of corticotropes by CRH. Similar interactions might underlie chronic stress states.
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Affiliation(s)
- Ferdinand Roelfsema
- Department of Endocrinology and Metabolism, Leiden University Medical Center, 2333ZA Leiden, The Netherlands
| | - Paul Aoun
- Endocrine Research Unit, Mayo School of Graduate Medical Education, Center for Translational Science Activities, Mayo Clinic, Rochester, Minnesota 55902
| | - Paul Y. Takahashi
- Primary Care Internal Medicine, Mayo Clinic, Rochester, Minnesota 55902
| | - Dana Erickson
- Endocrine Research Unit, Mayo School of Graduate Medical Education, Center for Translational Science Activities, Mayo Clinic, Rochester, Minnesota 55902
| | - Rebecca Yang
- Endocrine Research Unit, Mayo School of Graduate Medical Education, Center for Translational Science Activities, Mayo Clinic, Rochester, Minnesota 55902
| | - Johannes D. Veldhuis
- Endocrine Research Unit, Mayo School of Graduate Medical Education, Center for Translational Science Activities, Mayo Clinic, Rochester, Minnesota 55902
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van der Spoel E, Jansen SW, Akintola AA, Ballieux BE, Cobbaert CM, Slagboom PE, Blauw GJ, Westendorp RGJ, Pijl H, Roelfsema F, van Heemst D. Growth hormone secretion is diminished and tightly controlled in humans enriched for familial longevity. Aging Cell 2016; 15:1126-1131. [PMID: 27605408 PMCID: PMC6398524 DOI: 10.1111/acel.12519] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/23/2016] [Indexed: 01/16/2023] Open
Abstract
Reduced growth hormone (GH) signaling has been consistently associated with increased health and lifespan in various mouse models. Here, we assessed GH secretion and its control in relation with human familial longevity. We frequently sampled blood over 24 h in 19 middle‐aged offspring of long‐living families from the Leiden Longevity Study together with 18 of their partners as controls. Circulating GH concentrations were measured every 10 min and insulin‐like growth factor 1 (IGF‐1) and insulin‐like growth factor binding protein 3 (IGFBP3) every 4 h. Using deconvolution analysis, we found that 24‐h total GH secretion was 28% lower (P = 0.04) in offspring [172 (128–216) mU L−1] compared with controls [238 (193–284) mU L−1]. We used approximate entropy (ApEn) to quantify the strength of feedback/feedforward control of GH secretion. ApEn was lower (P = 0.001) in offspring [0.45 (0.39–0.53)] compared with controls [0.66 (0.56–0.77)], indicating tighter control of GH secretion. No significant differences were observed in circulating levels of IGF‐1 and IGFBP3 between offspring and controls. In conclusion, GH secretion in human familial longevity is characterized by diminished secretion rate and more tight control. These data imply that the highly conserved GH signaling pathway, which has been linked to longevity in animal models, is also associated with human longevity.
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Affiliation(s)
- Evie van der Spoel
- Section Gerontology and Geriatrics; Department of Internal Medicine; Leiden University Medical Center; Leiden The Netherlands
| | - Steffy W. Jansen
- Section Gerontology and Geriatrics; Department of Internal Medicine; Leiden University Medical Center; Leiden The Netherlands
| | - Abimbola A. Akintola
- Section Gerontology and Geriatrics; Department of Internal Medicine; Leiden University Medical Center; Leiden The Netherlands
| | - Bart E. Ballieux
- Department of Clinical Chemistry and Laboratory Medicine; Leiden University Medical Center; Leiden The Netherlands
| | - Christa M. Cobbaert
- Department of Clinical Chemistry and Laboratory Medicine; Leiden University Medical Center; Leiden The Netherlands
| | - P. Eline Slagboom
- Section Molecular Epidemiology; Department of Medical Statistics; Leiden University Medical Center; Leiden The Netherlands
| | - Gerard Jan Blauw
- Section Gerontology and Geriatrics; Department of Internal Medicine; Leiden University Medical Center; Leiden The Netherlands
| | - Rudi G. J. Westendorp
- Section Gerontology and Geriatrics; Department of Internal Medicine; Leiden University Medical Center; Leiden The Netherlands
- Department of Public Health and Center of Healthy Aging; University of Copenhagen; Copenhagen Denmark
| | - Hanno Pijl
- Section Endocrinology; Department of Internal Medicine; Leiden University Medical Center; Leiden The Netherlands
| | - Ferdinand Roelfsema
- Section Endocrinology; Department of Internal Medicine; Leiden University Medical Center; Leiden The Netherlands
| | - Diana van Heemst
- Section Gerontology and Geriatrics; Department of Internal Medicine; Leiden University Medical Center; Leiden The Netherlands
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Roelfsema F, Veldhuis JD. Growth Hormone Dynamics in Healthy Adults Are Related to Age and Sex and Strongly Dependent on Body Mass Index. Neuroendocrinology 2016; 103:335-44. [PMID: 26228064 PMCID: PMC4731317 DOI: 10.1159/000438904] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/09/2015] [Accepted: 07/15/2015] [Indexed: 11/19/2022]
Abstract
BACKGROUND Studies on 24-hour growth hormone (GH) secretion are rare. The influences of sex, age, and adiposity are well recognized but generally derived from specific, selected subject groups, not spanning sexes, many age decades, and a range of body weights. OBJECTIVE Our goal was to investigate GH dynamics in a group of 130 healthy adult subjects, both men and women, across 5 age decades as well as a 2.5-fold range of body mass index (BMI) values. METHODS GH was measured by a sensitive immunofluorometric assay. Secretion parameters were quantified by automated deconvolution and relative pattern randomness by approximate entropy (ApEn). RESULTS The median age was 40 years (range 20-77). The median BMI was 26 (range 18.3-49.8). Pulsatile 24-hour GH secretion was negatively correlated with age (p = 0.002) and BMI (p < 0.0001). Basal GH secretion negatively correlated with BMI (p = 0.003) but not with age. The sex- dependent GH secretion (greater in women) was no longer detectable after 50 years of age. Insulin-like growth factor (IGF)-1 levels were lower in women over 50 years of age compared with men of a similar age. ApEn showed an age-related increase in both sexes and was higher in premenopausal and postmenopausal women than in men of comparable age (p < 0.0001). A single fasting GH measurement is not informative of 24-hour GH secretion. CONCLUSIONS BMI dominates the negative regulation of 24-hour GH secretion across 5 decades of age in this up till now largest cohort of healthy adults who underwent 24-hour blood sampling. Sex also impacts GH secretion before the age of 50 years as well as its regularity at all ages. Differences in serum IGF-1 partly depend on the pre- or postmenopausal state. Finally, a single GH measurement is not informative of 24-hour GH secretion.
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Affiliation(s)
- Ferdinand Roelfsema
- Department of Endocrinology and Metabolism, Leiden University Medical Center, Leiden, the Netherlands
| | - Johannes D. Veldhuis
- Endocrine Research Unit, Mayo Clinic College of Medicine, Rochester, MN 55905, USA
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Cherian KE, Jebasingh FK, Kapoor N, Paul TV. Klinefelter syndrome with low gonadotropin levels. BMJ Case Rep 2015; 2015:bcr-2015-213333. [PMID: 26715140 DOI: 10.1136/bcr-2015-213333] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022] Open
Abstract
Klinefelter syndrome is usually characterised by the presence of a eunuchoid body habitus and testes that are usually small and firm, with low testosterone, and elevated luteinising hormone and follicle-stimulating hormone levels, consistent with hypergonadotropic hypogonadism. Low levels of gonadotropins in karyotypically proven cases are not expected, they are extremely rare occurrences. We report a case of a patient who was diagnosed to have Klinefelter syndrome (47 XXY) with low gonadotropin levels. The rest of his anterior pituitary hormonal profile was normal with no lesions in the pituitary gland on imaging. He was continued on androgen replacement therapy.
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Affiliation(s)
| | - Felix K Jebasingh
- Department of Endocrinology, Christian Medical College, Vellore, Tamil Nadu, India
| | - Nitin Kapoor
- Department of Endocrinology, Christian Medical College, Vellore, Tamil Nadu, India
| | - Thomas Vizhalil Paul
- Department of Endocrinology, Christian Medical College, Vellore, Tamil Nadu, India
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Characterization of the Hypothalamic-Pituitary-Adrenal-Axis in Familial Longevity under Resting Conditions. PLoS One 2015; 10:e0133119. [PMID: 26193655 PMCID: PMC4508039 DOI: 10.1371/journal.pone.0133119] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2015] [Accepted: 06/24/2015] [Indexed: 12/04/2022] Open
Abstract
Objective The hypothalamic-pituitary-adrenal (HPA)-axis is the most important neuro-endocrine stress response system of our body which is of critical importance for survival. Disturbances in HPA-axis activity have been associated with adverse metabolic and cognitive changes. Humans enriched for longevity have less metabolic and cognitive disturbances and therefore diminished activity of the HPA axis may be a potential candidate mechanism underlying healthy familial longevity. Here, we compared 24-h plasma ACTH and serum cortisol concentration profiles and different aspects of the regulation of the HPA-axis in offspring from long-lived siblings, who are enriched for familial longevity and age-matched controls. Design Case-control study within the Leiden Longevity study cohort consisting of 20 middle-aged offspring of nonagenarian siblings (offspring) together with 18 partners (controls). Methods During 24 h, venous blood was sampled every 10 minutes for determination of circulatory ACTH and cortisol concentrations. Deconvolution analysis, cross approximate entropy analysis and ACTH-cortisol-dose response modeling were used to assess, respectively, ACTH and cortisol secretion parameters, feedforward and feedback synchrony and adrenal gland ACTH responsivity. Results Mean (95% Confidence Interval) basal ACTH secretion was higher in male offspring compared to male controls (645 (324-1286) ngl/L/24 h versus 240 (120-477) ng/L/24 h, P = 0.05). Other ACTH and cortisol secretion parameters did not differ between offspring and controls. In addition, no significant differences in feedforward and feedback synchrony and adrenal gland ACTH responsivity were observed between groups. Conclusions These results suggest that familial longevity is not associated with major differences in HPA-axis activity under resting conditions, although modest, sex-specific differences may exist between groups that might be clinically relevant.
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Jansen SW, Akintola AA, Roelfsema F, van der Spoel E, Cobbaert CM, Ballieux BE, Egri P, Kvarta-Papp Z, Gereben B, Fekete C, Slagboom PE, van der Grond J, Demeneix BA, Pijl H, Westendorp RGJ, van Heemst D. Human longevity is characterised by high thyroid stimulating hormone secretion without altered energy metabolism. Sci Rep 2015; 5:11525. [PMID: 26089239 PMCID: PMC4473605 DOI: 10.1038/srep11525] [Citation(s) in RCA: 58] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2014] [Accepted: 05/28/2015] [Indexed: 12/25/2022] Open
Abstract
Few studies have included subjects with the propensity to reach old age in good health, with the aim to disentangle mechanisms contributing to staying healthier for longer. The hypothalamic-pituitary-thyroid (HPT) axis maintains circulating levels of thyroid stimulating hormone (TSH) and thyroid hormone (TH) in an inverse relationship. Greater longevity has been associated with higher TSH and lower TH levels, but mechanisms underlying TSH/TH differences and longevity remain unknown. The HPT axis plays a pivotal role in growth, development and energy metabolism. We report that offspring of nonagenarians with at least one nonagenarian sibling have increased TSH secretion but similar bioactivity of TSH and similar TH levels compared to controls. Healthy offspring and spousal controls had similar resting metabolic rate and core body temperature. We propose that pleiotropic effects of the HPT axis may favour longevity without altering energy metabolism.
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Affiliation(s)
- S W Jansen
- Department of Gerontology and Geriatrics, Leiden University Medical Centre, Leiden, The Netherlands
| | - A A Akintola
- Department of Gerontology and Geriatrics, Leiden University Medical Centre, Leiden, The Netherlands
| | - F Roelfsema
- Department of Medicine, Section Endocrinology, Leiden University Medical Centre, Leiden, The Netherlands
| | - E van der Spoel
- Department of Gerontology and Geriatrics, Leiden University Medical Centre, Leiden, The Netherlands
| | - C M Cobbaert
- Department of Clinical Chemistry and Laboratory Medicine, Leiden University Medical Centre, Leiden, The Netherlands
| | - B E Ballieux
- Department of Clinical Chemistry and Laboratory Medicine, Leiden University Medical Centre, Leiden, The Netherlands
| | - P Egri
- 1] Department of Endocrine Neurobiology, Institute of Experimental Medicine, Hungarian Academy of Sciences, Budapest, Hungary [2] Semmelweis University, János Szentágothai PhD School of Neurosciences, Budapest, H-1085 Hungary
| | - Z Kvarta-Papp
- Department of Endocrine Neurobiology, Institute of Experimental Medicine, Hungarian Academy of Sciences, Budapest, Hungary
| | - B Gereben
- Department of Endocrine Neurobiology, Institute of Experimental Medicine, Hungarian Academy of Sciences, Budapest, Hungary
| | - C Fekete
- 1] Department of Endocrine Neurobiology, Institute of Experimental Medicine, Hungarian Academy of Sciences, Budapest, Hungary [2] Department of Medicine, Division of Endocrinology, Diabetes and Metabolism, Tupper Research Institute, Tufts Medical Centre, Boston, MA, USA
| | - P E Slagboom
- Section of Molecular Epidemiology, Department of Medical Statistics, Leiden University Medical Centre, Leiden, The Netherlands
| | - J van der Grond
- Department of Radiology, Leiden University Medical Centre, Leiden, The Netherlands
| | - B A Demeneix
- UMR 7221 CNRS / MNHN Evolution des Régulations Endocriniennes, Département Régulations, Développement et Diversité Moléculaire, Muséum National d'Histoire Naturelle, Paris, France
| | - H Pijl
- Department of Medicine, Section Endocrinology, Leiden University Medical Centre, Leiden, The Netherlands
| | - R G J Westendorp
- 1] Department of Gerontology and Geriatrics, Leiden University Medical Centre, Leiden, The Netherlands [2] Department of Public Health, University of Copenhagen, Denmark
| | - D van Heemst
- Department of Gerontology and Geriatrics, Leiden University Medical Centre, Leiden, The Netherlands
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Roelfsema F, Pereira AM, Veldhuis JD. Impact of Adiposity and Fat Distribution on the Dynamics of Adrenocorticotropin and Cortisol Rhythms. Curr Obes Rep 2014; 3:387-95. [PMID: 26626915 DOI: 10.1007/s13679-014-0118-7] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Obesity impacts many hormonal systems, including pituitary hormones, as well as insulin and leptin. In this review we discuss articles which investigate the influence of obesity on the hypothalamic-pituitary-adrenal (HPA) axis. Different techniques have been used to assess the function of the HPA-axis in obesity, including measuring fasting and/or late evening levels of adrenocorticotropic hormone (ACTH) and (free) cortisol in plasma and saliva, studying feedback with dexamethasone or cortisol, and evaluating responsiveness of the system to corticotropin-releasing hormone (CRH) and arginine vasopressin (AVP) or ACTH 1-29. In addition, more elaborate studies investigated 24-h secretion patterns, analyzed with deconvolution techniques to quantitate pulsatile secretion rates of cortisol and less often ACTH. Other investigators used timed infusions of labeled cortisol for the estimation of the 24-h secretion rate, clearance rate and distribution volume. Many studies relied on the 24-h urinary excretion of free cortisol, but for quantitation of the 24-h secretion, measurement of all cortisol-derived metabolites is required. Several studies have applied modern liquid chromatography-tandem-mass spectrometry techniques to measure these metabolites. The picture emerging from all these studies is that, first, ACTH secretion is amplified, likely via enhanced forward drive; and, second, serum cortisol levels are normal or even low, associated with a normal 24-h cortisol secretion per liter distribution volume determined by deconvolution, but enhanced when based on the increased total distribution volume associated with obesity. Increased cortisol secretion was also established by isotope dilution studies and reports based on the measurement of all urinary cortisol metabolites. The responsiveness of the adrenal gland to ACTH is diminished. The studies do not address quantitative aspects of cortisol-cortisone metabolism on individual organs, including liver, central and peripheral fat, intestine, skin, and muscle.
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Affiliation(s)
- Ferdinand Roelfsema
- Department of Endocrinology and Metabolic Diseases, Leiden University Medical Center, Albinusdreef 2, 2333ZA, Leiden, The Netherlands.
| | - Alberto M Pereira
- Department of Endocrinology and Metabolic Diseases, Leiden University Medical Center, Albinusdreef 2, 2333ZA, Leiden, The Netherlands
| | - Johannes D Veldhuis
- Endocrine Research Unit, Mayo Medical and Graduate Schools, Clinical Translational Research Center, Mayo Clinic, Rochester, MN, 55901, USA
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Roelfsema F, Pereira AM, Biermasz NR, Veldhuis JD. Hormone secretion by pituitary adenomas is characterized by increased disorderliness and spikiness but more regular pulsing. J Clin Endocrinol Metab 2014; 99:3836-44. [PMID: 25014002 PMCID: PMC4184075 DOI: 10.1210/jc.2014-2363] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
CONTEXT Hormone secretion by functioning pituitary tumors is characterized by increased basal (nonpulsatile) secretion, enhanced pulse frequency, amplified pulse mass, and increased disorderliness. OBJECTIVE The objective of the study was to quantify (subtle) abnormalities of hormone secretion by pituitary adenomas and the influence of selective pituitary surgery and suppressive medications on these parameters. METHODS Approximate entropy (ApEn) was quantified with a refined algorithm, spikiness by a new method to evaluate sudden short-lived increases in hormone levels, and pulsing regularity, determined with a fully automated deconvolution program. These 3 distinct measures of secretory disruption were compared in untreated and treated patients with acromegaly, prolactinoma, and Cushing's disease together with matching profiles in healthy controls. RESULTS ApEn and spikiness were markedly increased in all untreated patient groups and normalized after pituitary surgery in acromegaly and hypercortisolism. In contrast, hormone-suppressive medical treatment in acromegaly and prolactinoma did not normalize ApEn. Spikiness normalized in acromegalic patients but not in prolactinoma. GH and cortisol pulsing regularity was elevated in acromegaly and Cushing's disease, respectively, and normalized after surgery. Medical treatment caused normalization of pulsing regularity in acromegaly but not in prolactinoma patients. CONCLUSION This study extends the understanding of disorganized hormone secretion by hyperfunctioning pituitary adenomas. The new findings are increased spikiness in all 3 tumor groups and increased pulsing regularity in GH- and ACTH-secreting adenomas. The mechanisms behind the marked pattern irregularity and the selective normalization by surgical and medical therapies are not established yet but may include diminished feedback signaling in addition to the anatomical and functional disorganization of intrapituitary cell networks.
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Affiliation(s)
- Ferdinand Roelfsema
- Department of Endocrinology and Metabolic Diseases (F.R., A.M.P., N.R.B.), Leiden University Medical Center, 2333ZA Leiden, The Netherlands; and Endocrine Research Unit (J.D.V.), Mayo Medical and Graduate Schools, Clinical Translational Research Center, Mayo Clinic, Rochester, Minnesota 55901
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Zhang Y, Yu L, Jin W, Ao M. Effect of ethanolic extract of Lepidium meyenii Walp on serum hormone levels in ovariectomized rats. Indian J Pharmacol 2014; 46:416-9. [PMID: 25097281 PMCID: PMC4118536 DOI: 10.4103/0253-7613.135955] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/22/2013] [Revised: 08/21/2013] [Accepted: 05/15/2014] [Indexed: 12/01/2022] Open
Abstract
OBJECTIVE To evaluate the effect of long-term ethanol extract of Lepidium meyenii (Maca) on serum hormone levels in ovariectomized (OVX) rats and compare them with the effect of diethylstilbestrol. MATERIALS AND METHODS Fifty female Sprague-Dawley rats were ovariectomized or sham operated. Both sham and OVX control groups (n = 10, respectively) received the vehicle. The remaining OVX rats were oral administrated with ethanol extract of Maca (0.096, or 0.24g/kg; n = 10, respectively) and diethylstilbestrol (0.05 mg/kg; n = 10). The treatment continued for 28 weeks. At week 12 and week 28, the blood of rats was collected and serum hormone levels, including estradiol (E2), testosterone (T) and follicle-stimulating hormone (FSH) were measured by radioimmunoassay. RESULTS At week 12, the levels of serum E2 were slightly higher in Maca groups than that in OVX group; T levels were significantly decreased; and FSH levels were advanced slightly in Maca groups than that in sham group. After 28 weeks administration, serum E2 levels in Maca-treated animals did not differ significantly from sham control, the low dose of Maca increased serum E2 levels, and Maca prevented increase in serum FSH levels compared with OVX group. CONCLUSIONS Long-term Maca supply modulates endocrine hormone balance in OVX rats, especially it decreases enhanced FSH levels. It is proposed that Maca may become a potential choice for postmenopausal women.
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Affiliation(s)
- Yongzhong Zhang
- Department of Pharmacology, Medical School, Wuhan University of Science and Technology, Wuhan, China
| | - Longjiang Yu
- School of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, China
| | - Wenwen Jin
- School of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, China
| | - Mingzhang Ao
- School of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, China
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Sharma AN, Aoun P, Wigham JR, Weist SM, Veldhuis JD. Estradiol, but not testosterone, heightens cortisol-mediated negative feedback on pulsatile ACTH secretion and ACTH approximate entropy in unstressed older men and women. Am J Physiol Regul Integr Comp Physiol 2014; 306:R627-35. [PMID: 24573184 DOI: 10.1152/ajpregu.00551.2013] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
How sex steroids modulate glucocorticoid feedback on the hypothalamic-pituitary-corticotrope (HPC) unit is controversial in humans. We postulated that testosterone (T) in men and estradiol (E2) in women govern unstressed cortisol-mediated negative feedback on ACTH secretion. To test this hypothesis, 24 men and 24 women age 58 ± 2.4 yr were pretreated with leuprolide and either sex steroid (E2 in women, T in men) or placebo addback. Placebo or ketoconazole (KTCZ) was administered overnight to inhibit adrenal steroidogenesis during overnight 14-h intravenous infusions of saline or cortisol in a continuous versus pulsatile manner to test for feedback differences. ACTH was measured every 10 min during the last 8 h of the infusions. The main outcome measures were mean ACTH concentrations, pulsatile ACTH secretion, and ACTH approximate entropy (ApEn). ACTH concentrations were lower in women than men (P < 0.01), and in women in the E2+ compared with E2- group under both continuous (P = 0.01) and pulsatile (P = 0.006) cortisol feedback, despite higher cortisol binding globulin and lower free cortisol levels in women than men (P < 0.01). In the combined groups, under both modes of cortisol addback, ACTH concentrations, pulsatile ACTH secretion, and ACTH secretory-burst mass correlated negatively and univariately with E2 levels (each P < 0.005). E2 also suppressed ACTH ApEn (process randomness) during continuous cortisol feedback (P = 0.004). T had no univariate effect but was a positive correlate of ACTH when assessed jointly with E2 (negative) under cortisol pulses. In conclusion, sex steroids modulate selective gender-related hypothalamic-pituitary adrenal-axis adaptations to cortisol feedback in unstressed humans.
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Affiliation(s)
- Animesh N Sharma
- Endocrine Research Unit, Mayo School of Graduate Medical Education, Center for Translational Science Activities, Mayo Clinic, Rochester, Minnesota
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Norman C, Rollene NL, Erickson D, Miles JM, Bowers CY, Veldhuis JD. Estradiol regulates GH-releasing peptide's interactions with GH-releasing hormone and somatostatin in postmenopausal women. Eur J Endocrinol 2014; 170:121-9. [PMID: 24114435 PMCID: PMC3892701 DOI: 10.1530/eje-13-0733] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
OBJECTIVE Estrogen stimulates pulsatile secretion of GH, via mechanisms that are largely unknown. An untested hypothesis is that estradiol (E₂) drives GH secretion by amplifying interactions among GH-releasing hormone (GHRH), somatostatin (SS), and GH-releasing peptide (GHRP). DESIGN The design comprised double-blind randomized prospective administration of transdermal E₂ vs placebo to healthy postmenopausal women (n=24) followed by pulsatile GHRH or SS infusions for 13 h overnight with or without continuous GHRP2 stimulation. METHODS End points were mean concentrations, deconvolved secretion, and approximate entropy (ApEn; a regularity measure) of GH. RESULTS By generalized ANOVA models, it was observed that E₂ vs placebo supplementation: i) augmented mean (13-h) GH concentrations (P=0.023), GHRH-induced pulsatile GH secretion over the first 3 h (P=0.0085) and pulsatile GH secretion over the next 10 h (P=0.054); ii) increased GHRP-modulated (P=0.022) and SS-modulated (P<0.001) GH ApEn; and iii) did not amplify GHRH/GHRP synergy during pulsatile GH secretion. By linear regression, E₂ concentrations were found to be positively correlated with GH secretion during GHRP2 infusion (P=0.022), whereas BMI was found to be negatively correlated with GH secretion during GHRH (P=0.006) and combined GHRH/GHRP (P=0.015) stimulation. E₂ and BMI jointly determined triple (combined l-arginine, GHRH, and GHRP2) stimulation of GH secretion after saline (R²=0.44 and P=0.003) and pulsatile GHRH (R²=0.39 and P=0.013) infusions. CONCLUSION In summary, in postmenopausal women, E₂ supplementation augments the amount (mass) and alters the pattern (regularity) of GH secretion via interactions among GHRH, SS, GHRP, and BMI. These outcomes introduce a more complex model of E₂ supplementation in coordinating GH secretion in aging women.
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Abstract
Thyroid hormones are extremely important for metabolism, development, and growth during the lifetime. The hypothalamo-pituitary-thyroid axis is precisely regulated for these purposes. Much of our knowledge of this hormonal axis is derived from experiments in animals and mutations in man. This review examines the hypothalamo-pituitary-thyroid axis particularly in relation to the regulated 24-hour serum TSH concentration profiles in physiological and pathophysiological conditions, including obesity, primary hypothyroidism, pituitary diseases, psychiatric disorders, and selected neurological diseases. Diurnal TSH rhythms can be analyzed with novel and precise techniques, eg, operator-independent deconvolution and approximate entropy. These approaches provide indirect insight in the regulatory components in pathophysiological conditions.
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Affiliation(s)
- Ferdinand Roelfsema
- Leiden University Medical Center, Department of Endocrinology and Metabolic Diseases, PO Box 9600, 2300 RC Leiden, The Netherlands.
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Veldhuis JD, Norman C, Miles JM, Bowers CY. Sex steroids, GHRH, somatostatin, IGF-I, and IGFBP-1 modulate ghrelin's dose-dependent drive of pulsatile GH secretion in healthy older men. J Clin Endocrinol Metab 2012; 97:4753-60. [PMID: 22990092 PMCID: PMC3513533 DOI: 10.1210/jc.2012-2567] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
CONTEXT Ghrelin is a potent endogenous stimulator of GH secretion. However, clinical factors that regulate ghrelin dose-responsiveness are incompletely defined. OBJECTIVE The aim of the study was to test the multipathway hypothesis that testosterone (T) and estradiol, GHRH, and somatostatin (SS) jointly modulate ghrelin's action. DESIGN/PARTICIPANTS/SETTING Healthy older men (n = 21) participated in a double-blind, prospectively randomized, placebo (Pl)-controlled study in a Clinical Translational Research Center. INTERVENTIONS To create a range of sex-steroid milieus, men received leuprolide + Pl (n = 10) or leuprolide + T addback (n = 11). Sixteen to 21 d later, subjects received three separate randomly ordered overnight constant i.v. infusions of saline, GHRH, and SS. Interactions between the peptide clamp and ghrelin were tested by superimposed injections of four randomly ordered bolus i.v. doses of ghrelin (0.03, 0.135, 0.60, and 2.7 μg/kg). GH was measured every 10 min, and GH responses were assessed by nonlinear dose-response analysis. Linear associations were assessed by stepwise regression. OUTCOME MEASURES/RESULTS The descending numerical order of ghrelin efficacy (maximal GH secretory-burst mass; micrograms/liter) was 107 (GHRH + Pl), 104 (GHRH + T), 73 (saline + T), 73 (SS + T), 60 (saline + Pl), and 52 (SS + Pl) [means], wherein SS + T exceeded SS + Pl. GHRH and IGF binding protein-1 augmented, whereas IGF-I attenuated ghrelin potency. Age and IGF-I decreased ghrelin/GHRH synergy. Ghrelin sensitivity was independent of interventions. CONCLUSIONS These studies introduce composite regulatory effects of sex hormones, GHRH, SS, IGF binding protein-1, and IGF-I on ghrelin dose-responsiveness, suggesting multipathway modulation of GH-secretagogue action.
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Affiliation(s)
- Johannes D Veldhuis
- Endocrine Research Unit, Mayo School of Graduate Medical Education, National Institutes of Health Center for Translational Science Activities, Mayo Clinic, Rochester, Minnesota 55905, USA.
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Veldhuis JD, Liu PY, Takahashi PY, Keenan DM. Dynamic testosterone responses to near-physiological LH pulses are determined by the time pattern of prior intravenous LH infusion. Am J Physiol Endocrinol Metab 2012; 303:E720-8. [PMID: 22811471 PMCID: PMC3468430 DOI: 10.1152/ajpendo.00200.2012] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The long-lived glycoprotein hormone, human chorionic gonadotropin (hCG), downregulates testosterone (T) biosynthesis in vitro and in vivo in animals and humans. The degree to which short-lived pulses of pituitary luteinizing hormone (LH) do so, particularly at physiological concentrations, is not known. We test the hypothesis that continuous LH infusion compared with bolus injections of LH every 1 h or every 2 h overnight downregulates T secretory responses to a subsequent fixed template of three consecutive intravenous pulses of a physiological amount of recombinant human (rh) LH (triple stimulus). Nineteen healthy men ages 18-49 yr each underwent four separate randomly ordered overnight gonadotropin-releasing hormone-receptor antagonist treatments with superimposed intravenous infusions of saline or rhLH (1-h pulses, 2-h pulses, or continuously). Each 12-h infusion protocol was followed by the triple rhLH-pulse stimulus the next morning. During the triple stimulus, basal (nonpulsatile) as well as total (basal plus pulsatile) T secretion was higher after overnight 2- and 1-h rhLH pulses than after continuous rhLH or saline delivery. Approximate entropy, a probabilistic measure of feedforward-induced irregularity of T concentration time series, was higher after 1-h rhLH pulses than after continuous rhLH. Analytical estimation of pulsatile rhLH-T dose-response measures revealed higher T secretory sensitivity and greater rhLH potency (lower EC₅₀) after exposure to 1-h than 2-h rhLH pulses. Collectively, these data indicate that in vivo dynamics of LH-stimulated T secretion under standardized conditions in men depend on the prior time mode of LH delivery in the bloodstream.
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Affiliation(s)
- Johannes D Veldhuis
- Endocrine Research Unit, Mayo School of Graduate Medical Education, Center for Translational Science Activities, Mayo Clinic, Rochester, MN, USA.
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Carroll BJ, Iranmanesh A, Keenan DM, Cassidy F, Wilson WH, Veldhuis JD. Pathophysiology of hypercortisolism in depression: pituitary and adrenal responses to low glucocorticoid feedback. Acta Psychiatr Scand 2012; 125:478-91. [PMID: 22211368 PMCID: PMC3893569 DOI: 10.1111/j.1600-0447.2011.01821.x] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
OBJECTIVE To test three theories of hypercortisolemia in depression-hypothalamic overdrive, impaired glucocorticoid feedback, or autonomous cortisol production. METHOD We applied an overnight low-cortisol feedback strategy by administering metyrapone to hypercortisolemic depressed in-patients and control subjects. RESULTS Under metyrapone, the increases of plasma adrenocorticotropic hormone (ACTH) concentrations and of basal and pulsatile ACTH secretion were not exaggerated in hypercortisolemic depressed patients compared with control subjects. ACTH approximate entropy (ApEn) did not differ at baseline or under metyrapone. Thus, neither hypothalamic overdrive nor irregular ACTH secretion was seen. We did not detect impaired cortisol feedback: the ACTH response was not reduced, and ApEn measures that are sensitive to feedback changes were comparable in both groups. Metyrapone disrupted cortisol secretory regularity in depressed and control subjects. On the baseline day, basal cortisol secretion was significantly increased and was highly irregular (high ApEn), and ACTH-cortisol cross-ApEn was markedly elevated in high-cortisol patients. CONCLUSION Classical feed-forward overdrive and impaired feedback theories of hypercortisolemia in depression were not supported. Depressive hypercortisolemia may result from alternative pathophysiological mechanisms involving irregular basal hypersecretion of cortisol, associated with adrenal enlargement, possibly through splanchnic sympathetic activation of the adrenal cortex.
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Affiliation(s)
| | - Ali Iranmanesh
- Endocrine Service, Medical Section, Salem Veterans Affairs Medical Center, Salem, VA 24153
| | - Daniel M. Keenan
- Department of Statistics, University of Virginia, Charlottesville, VA 22904
| | - Frederick Cassidy
- Department of Psychiatry, Duke University Medical Center, Durham, NC 27710
| | - William H. Wilson
- Department of Psychiatry, Duke University Medical Center, Durham, NC 27710
| | - Johannes D. Veldhuis
- Endocrine Research Unit, Mayo School of Graduate Medical Education, Center for Translational Science Activities, Mayo Clinic, 200 First Street SW, Rochester, MN 55905
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Wang X, Keenan DM, Pincus SM, Liu PY, Veldhuis JD. Oscillations in joint synchrony of reproductive hormones in healthy men. Am J Physiol Endocrinol Metab 2011; 301:E1163-73. [PMID: 21900124 PMCID: PMC3233781 DOI: 10.1152/ajpendo.00138.2011] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Negative-feedback (inhibitory) and positive-feedforward (stimulatory) processes regulate physiological systems. Whether such processes are themselves rhythmic is not known. Here, we apply cross-approximate entropy (cross-ApEn), a noninvasive measurement of joint (pairwise) signal synchrony, to inferentially assess hypothesized circadian and ultradian variations in feedback coupling. The data comprised simultaneous measurements of three pituitary and one peripheral hormone (LH, FSH, prolactin, and testosterone) in 12 healthy men each sampled every 10 min for 4 days (5,760 min). Ergodicity, due to the time series stationarity of the measurements over the 4 days, allows for effective estimation of parameters based upon the 12 subjects. Cross-ApEn changes were quantified via moving-window estimates applied to 4-day time series pairs. The resultant ordered windowed cross-ApEn series (in time) were subjected to power spectrum analysis. Rhythmicity was assessed against the null hypothesis of randomness using 1,000 simulated periodograms derived by shuffling the interpulse-interval hormone-concentration segments and redoing cross-ApEn windows and spectral analysis. By forward cross-ApEn analysis, paired LH-testosterone, LH-prolactin, and LH-FSH synchrony maintained dominant rhythms with periodicities of 18-22.5, 18, and 22.5 h, respectively (each P < 0.001). By reverse (feedback) cross-ApEn analysis, testosterone-LH, testosterone-prolactin, and testosterone-FSH synchrony cycles were 30, 18, and 30-45 h, respectively (each P ≤ 0.001). Significant 8- or 24-h rhythms were also detected in most linkages, and maximal bihormonal synchrony occurred consistently at ∼0400-0500. Collectively, these analyses demonstrate significant ultradian (<24 h), circadian (∼24 h), and infradian (>24 h) oscillations in pituitary-testis synchrony, wherein maximal biglandular coordination is strongly constrained to the early morning hours.
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Affiliation(s)
- Xin Wang
- Endocrine Research Unit, Mayo Clinic, Rochester, Minnesota 55905, USA
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Iranmanesh A, Rochester DF, Liu J, Veldhuis JD. Impaired adrenergic- and corticotropic-axis outflow during exercise in chronic obstructive pulmonary disease. Metabolism 2011; 60:1521-9. [PMID: 21632072 PMCID: PMC3181386 DOI: 10.1016/j.metabol.2011.03.018] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/20/2010] [Revised: 03/21/2011] [Accepted: 03/26/2011] [Indexed: 10/18/2022]
Abstract
Exercise stimulates coordinated release of the sympathoadrenal hormones adrenocorticotropic hormone (ACTH), cortisol, norepinephrine (NE), and epinephrine (Epi). The study hypothesis was that chronic obstructive pulmonary disease (COPD) is marked by heightened sympathoadrenal outflow at comparable relative workloads. The location of the study was at a clinical research unit. Eight healthy men and 9 men with stable COPD (forced expiratory volume at 1 second <75% predicted) were studied. Volunteers rested (baseline) or exercised at individual submaximal (35% ± 5%) or maximal oxygen consumption. Blood was sampled every 2 minutes for 40 minutes concurrently. Two-way analysis of covariance was applied to examine group (healthy/COPD) and exercise (3 levels) effects on ACTH, cortisol, NE, and Epi release and regularity (estimable by approximate entropy). The timing of peak hormone concentrations was Epi, 14 minutes; NE, 16 minutes; ACTH, 22 minutes; and cortisol, 34 minutes in both cohorts. Type of exercise regimen influenced all 4 hormones (each P < .001), and subject group (control vs COPD) affected cortisol (P < .001) and Epi (P = .048) responses. Exercise regimen and group together controlled ACTH, cortisol, and Epi (each P < .001), but not NE, responses. In particular, endocrine responses were attenuated in COPD compared with control subjects. Approximate entropy analysis also identified loss of maximal exercise-induced ACTH-secretory regularity in COPD patients (P = .042). These outcomes demonstrate impaired rather than augmented exercise-associated sympathocorticotropic-axis outflow in patients with COPD even when outcomes are normalized to maximal oxygen consumption, suggesting that factors other than fitness are at work.
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Affiliation(s)
- Ali Iranmanesh
- Endocrine Service, Medical Section, Salem Veterans Affairs Medical Center, Salem, VA 24153
| | - Dudley F. Rochester
- Division of Pulmonary and Critical Medicine, University of Virginia Health Sciences Center, Charlottesville, VA 22901
| | - Jing Liu
- Division of Pulmonary and Critical Medicine, University of Virginia Health Sciences Center, Charlottesville, VA 22901
| | - Johannes D. Veldhuis
- Endocrine Research Unit, Mayo School of Graduate Medical Education, Center for Translational Science Activities, Mayo Clinic, Rochester, MN 55905
- Corresponding author: Tel: (507) 255-0906, Fax: (507) 255-0901,
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Iranmanesh A, Lawson D, Dunn B, Veldhuis JD. Glucose ingestion selectively amplifies ACTH and cortisol secretory-burst mass and enhances their joint synchrony in healthy men. J Clin Endocrinol Metab 2011; 96:2882-8. [PMID: 21752898 PMCID: PMC3167666 DOI: 10.1210/jc.2011-0682] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
CONTEXT Glucose intake is associated with a variable increase in adrenal glucocorticoid secretion. HYPOTHESIS Glucose ingestion elevates cortisol secretion by 1) augmenting pulsatile ACTH release; and/or 2) enhancing ACTH-cortisol synchrony or dose-responsiveness. SUBJECTS Fifty-eight healthy men ages 19-78 yr with computed tomography-estimated abdominal visceral fat participated in the study. LOCATION The study was conducted at the Clinical Translational-Research Center and Veterans Affairs Medical Center. METHODS We conducted frequent sampling of plasma ACTH and cortisol concentrations after glucose vs. water ingestion in the fasting state, as well as deconvolution, approximate entropy, linear-regression, and dose-response analysis. OUTCOMES After water ingestion, age was a negative correlate of the mass of ACTH (P = 0.009; R(2) = 0.119) and of cortisol (P < 0.001; R(2) = 0.269) secreted per burst. Glucose ingestion abolished both relationships but amplified pulsatile ACTH (P = 0.009) and cortisol (P = 0.001) secretion. Glucose exposure selectively augmented the mass of ACTH (P < 0.001) and of cortisol (P = 0.004) secreted per burst without altering burst number or basal secretion. The increment in pulsatile ACTH strongly predicted the increment in pulsatile cortisol (P < 10(-4); R(2) = 0.325) secretion. Abdominal visceral fat positively forecast the glucose-induced increment in cortisol secretory-burst mass (P = 0.019). According to approximate entropy analysis, glucose input also enhanced the joint synchrony of ACTH-cortisol secretory patterns (P ≤ 0.001). Caloric intake did not affect analytical dose-response estimates of ACTH potency and efficacy or adrenal sensitivity. CONCLUSION Conjoint augmentation of the mass of ACTH and cortisol secreted per burst and enhancement of ACTH-cortisol synchrony underlie glucose-induced glucocorticoid secretion in healthy men. Visceral adiposity is a predictor of the glucose-stimulated increment in burst-like cortisol output, suggesting an additional possible mechanism for increased cardiovascular risk in abdominal obesity.
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Affiliation(s)
- Ali Iranmanesh
- Endocrine Section, Medical Service, Salem Veterans Affairs Medical Center, Salem, Virginia 24153, USA
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Veldhuis JD, Bowers CY. Regulated recovery of pulsatile growth hormone secretion from negative feedback: a preclinical investigation. Am J Physiol Regul Integr Comp Physiol 2011; 301:R1143-52. [PMID: 21795635 DOI: 10.1152/ajpregu.00293.2011] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Although stimulatory (feedforward) and inhibitory (feedback) dynamics jointly control neurohormone secretion, the factors that supervise feedback restraint are poorly understood. To parse the regulation of growth hormone (GH) escape from negative feedback, 25 healthy men and women were studied eight times each during an experimental GH feedback clamp. The clamp comprised combined bolus infusion of GH or saline and continuous stimulation by saline GH-releasing hormone (GHRH), GHRP-2, or both peptides after randomly ordered supplementation with placebo (both sexes) vs. E(2) (estrogen; women) and T (testosterone; men). Endpoints were GH pulsatility and entropy (a model-free measure of feedback quenching). Gender determined recovery of pulsatile GH secretion from negative feedback in all four secretagog regimens (0.003 ≤ P ≤ 0.017 for women>men). Peptidyl secretagog controlled the mass, number, and duration of feedback-inhibited GH secretory bursts (each, P < 0.001). E(2)/T administration potentiated both pulsatile (P = 0.006) and entropic (P < 0.001) modes of GH recovery. IGF-I positively predicted the escape of GH secretory burst number and mode (P = 0.022), whereas body mass index negatively forecast GH secretory burst number and mass (P = 0.005). The composite of gender, body mass index, E(2), IGF-I, and peptidyl secretagog strongly regulates the escape of pulsatile and entropic GH secretion from autonegative feedback. The ensemble factors identified in this preclinical investigation enlarge the dynamic model of GH control in humans.
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Affiliation(s)
- Johannes D Veldhuis
- Endocrine Research Unit, Mayo School of Graduate Medical Education, Center for Translational Science Activities, Mayo Clinic, Rochester, MN 55905, USA.
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Veldhuis JD, Erickson D, Miles JM, Bowers CY. Complex regulation of GH autofeedback under dual-peptide drive: studies under a pharmacological GH and sex steroid clamp. Am J Physiol Endocrinol Metab 2011; 300:E1158-65. [PMID: 21467302 PMCID: PMC3118586 DOI: 10.1152/ajpendo.00054.2011] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
To test the postulate that sex difference, sex steroids, and peptidyl secretagogues control GH autofeedback, 11 healthy postmenopausal women and 14 older men were each given 1) a single iv pulse of GH to enforce negative feedback and 2) continuous iv infusion of saline vs. combined GHRH/GHRP-2 to drive feedback escape during pharmacological estradiol (E(2); women) or testosterone (T; men) supplementation vs. placebo in a double-blind, prospectively randomized crossover design. By three-way ANCOVA, sex difference, sex hormone treatment, peptide stimulation, and placebo/saline responses (covariate) controlled total (integrated) GH recovery during feedback (each P < 0.001). Both sex steroid milieu (P = 0.019) and dual-peptide stimulation (P < 0.001) determined nadir (maximally feedback-suppressed) GH concentrations. E(2)/T exposure elevated nadir GH concentrations during saline infusion (P = 0.003), whereas dual-peptide infusion did so independently of T/E(2) and sex difference (P = 0.001). All three of sex difference (P = 0.001), sex steroid treatment (P = 0.005), and double-peptide stimulation (P < 0.001) augmented recovery of peak (maximally feedback-escaped) GH concentrations. Peak GH responses to dual-peptidyl agonists were greater in women than in men (P = 0.016). E(2)/T augmented peak GH recovery during saline infusion (P < 0.001). Approximate entropy analysis corroborated independent effects of sex steroid treatment (P = 0.012) and peptide infusion (P < 0.001) on GH regularity. In summary, sex difference, sex steroid supplementation, and combined peptide drive influence nadir, peak, and entropic measurements of GH release under controlled negative feedback. To the degree that the pharmacological sex steroid, GH, and dual-peptide clamps provide prephysiological regulatory insights, these outcomes suggest major determinants of pulsatile GH secretion in the feedback domain.
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Affiliation(s)
- Johannes D Veldhuis
- Endocrine Research Unit, Mayo School of Graduate Medical Education, Center for Translational Science Activities, MayoClinic, Rochester, MN 55905, USA.
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Veldhuis JD, Takahashi PY, Keenan DM, Liu PY, Mielke KL, Weist SM. Age disrupts androgen receptor-modulated negative feedback in the gonadal axis in healthy men. Am J Physiol Endocrinol Metab 2010; 299:E675-82. [PMID: 20682842 PMCID: PMC2957871 DOI: 10.1152/ajpendo.00300.2010] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Testosterone (T) exerts negative feedback on the hypothalamo-pituitary (GnRH-LH) unit, but the relative roles of the CNS and pituitary are not established. We postulated that relatively greater LH responses to flutamide (brain-permeant antiandrogen) than bicalutamide (brain-impermeant antiandrogen) should reflect greater feedback via CNS than pituitary/peripheral androgen receptor-dependent pathways. To this end, 24 healthy men ages 20-73 yr, BMI 21-32 kg/m2, participated in a prospective, placebo-controlled, randomized, double-blind crossover study of the effects of antiandrogen control of pulsatile, basal, and entropic (pattern regularity) measurements of LH secretion. Analysis of covariance revealed that flutamide but not bicalutamide 1) increased pulsatile LH secretion (P = 0.003), 2) potentiated the age-related abbreviation of LH secretory bursts (P = 0.025), 3) suppressed incremental GnRH-induced LH release (P = 0.015), and 4) decreased the regularity of GnRH-stimulated LH release (P = 0.012). Furthermore, the effect of flutamide exceeded that of bicalutamide in 1) raising mean LH (P = 0.002) and T (P = 0.017) concentrations, 2) accelerating LH pulse frequency (P = 0.013), 3) amplifying total (basal plus pulsatile) LH (P = 0.002) and T (P < 0.001) secretion, 4) shortening LH secretory bursts (P = 0.032), and 5) reducing LH secretory regularity (P < 0.001). Both flutamide and bicalutamide elevated basal (nonpulsatile) LH secretion (P < 0.001). These data suggest the hypothesis that topographically selective androgen receptor pathways mediate brain-predominant and pituitary-dependent feedback mechanisms in healthy men.
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Affiliation(s)
- Johannes D Veldhuis
- Mayo School of Graduate Medical Education, Mayo Clinic, 200 First St. SW/Mayo Clinic, Rochester, MN 55905, USA.
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Redman LM, Veldhuis JD, Rood J, Smith SR, Williamson D, Ravussin E. The effect of caloric restriction interventions on growth hormone secretion in nonobese men and women. Aging Cell 2010; 9:32-9. [PMID: 19878147 DOI: 10.1111/j.1474-9726.2009.00530.x] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
Lifespan in rodents is prolonged by caloric restriction (CR) and by mutations affecting the somatotropic axis. It is not known if CR can alter the age-associated decline in growth hormone (GH), insulin-like growth factor (IGF)-1 and GH secretion. To evaluate the effect of CR on GH secretory dynamics; forty-three young (36.8 +/- 1.0 years), overweight (BMI 27.8 +/- 0.7) men (n = 20) and women (n = 23) were randomized into four groups; control = 100% of energy requirements; CR = 25% caloric restriction; CR + EX = 12.5% CR + 12.5% increase in energy expenditure by structured exercise; LCD = low calorie diet until 15% weight reduction followed by weight maintenance. At baseline and after 6 months, body composition (DXA), abdominal visceral fat (CT) 11 h GH secretion (blood sampling every 10 min for 11 h; 21:00-08:00 hours) and deconvolution analysis were measured. After 6 months, weight (control: -1 +/- 1%, CR: -10 +/- 1%, CR + EX: -10 +/- 1%, LCD: -14 +/- 1%), fat mass (control: -2 +/- 3%, CR: -24 +/- 3%, CR + EX: -25 +/- 3%, LCD: -31 +/- 2%) and visceral fat (control: -2 +/- 4%, CR: -28 +/- 4%, CR + EX: -27 +/- 3%, LCD: -36 +/- 2%) were significantly (P < 0.001) reduced in the three intervention groups compared to control. Mean 11 h GH concentrations were not changed in CR or control but increased in CR + EX (P < 0.0001) and LCD (P < 0.0001) because of increased secretory burst mass (CR + EX: 34 +/- 13%, LCD: 27 +/- 22%, P < 0.05) and amplitude (CR + EX: 34 +/- 14%, LCD: 30 +/- 20%, P < 0.05) but not to changes in secretory burst frequency or GH half-life. Fasting ghrelin was significantly increased from baseline in all three intervention groups; however, total IGF-1 concentrations were increased only in CR + EX (10 +/- 7%, P < 0.05) and LCD (19 +/- 4%, P < 0.001). A 25% CR diet for 6 months does not change GH, GH secretion or IGF-1 in nonobese men and women.
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Affiliation(s)
- Leanne M Redman
- Pennington Biomedical Research Center, Baton Rouge, LA, USA.
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Roelfsema F, Pereira AM, Adriaanse R, Endert E, Fliers E, Romijn JA, Veldhuis JD. Thyrotropin secretion in mild and severe primary hypothyroidism is distinguished by amplified burst mass and Basal secretion with increased spikiness and approximate entropy. J Clin Endocrinol Metab 2010; 95:928-34. [PMID: 19965923 DOI: 10.1210/jc.2009-1959] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
CONTEXT Twenty-four-hour TSH secretion profiles in primary hypothyroidism have been analyzed with methods no longer in use. The insights afforded by earlier methods are limited. OBJECTIVE We studied TSH secretion in patients with primary hypothyroidism (eight patients with severe and eight patients with mild hypothyroidism) with up-to-date analytical tools and compared the results with outcomes in 38 healthy controls. DESIGN AND METHODS Patients and controls underwent a 24-h study with 10-min blood sampling. TSH data were analyzed with a newly developed automated deconvolution program, approximate entropy, spikiness assessment, and cosinor regression. RESULTS Both basal and pulsatile TSH secretion rates were increased in hypothyroid patients, the latter by increased burst mass with unchanged frequency. Secretory regularity (approximate entropy) was diminished, and spikiness was increased only in patients with severe hypothyroidism. A diurnal TSH rhythm was present in all but two patients, although with an earlier acrophase in severe hypothyroidism. The estimated slow component of the TSH half-life was shortened in all patients. CONCLUSION Increased TSH concentrations in hypothyroidism are mediated by amplification of basal secretion and burst size. Secretory abnormalities quantitated by approximate entropy and spikiness were only present in patients with severe disease and thus are possibly related to the increased thyrotrope cell mass.
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Affiliation(s)
- Ferdinand Roelfsema
- Leiden University Medical Center, Department of Endocrinology and Metabolic Diseases, P.O. Box 9600, 2300 RC Leiden, The Netherlands.
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Gan EH, Quinton R. Physiological Significance of the Rhythmic Secretion of Hypothalamic and Pituitary Hormones. PROGRESS IN BRAIN RESEARCH 2010; 181:111-26. [DOI: 10.1016/s0079-6123(08)81007-2] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
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Veldhuis JD, Roelfsema F, Iranmanesh A, Carroll BJ, Keenan DM, Pincus SM. Basal, pulsatile, entropic (patterned), and spiky (staccato-like) properties of ACTH secretion: impact of age, gender, and body mass index. J Clin Endocrinol Metab 2009; 94:4045-52. [PMID: 19755477 PMCID: PMC2758736 DOI: 10.1210/jc.2009-1143] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
BACKGROUND Age, gender, and BMI determine ultradian modes of LH and GH secretion, viz., pulsatile, basal, pattern-defined regularity [approximate entropy (ApEn)] and spikiness (sharp, brief excursions). Whether the same determinants apply to ACTH secretion is not known. SETTING The study was conducted at a tertiary medical center. SUBJECTS We studied normal women (n = 22) and men (n = 26) [ages, 23-77 yr; body mass index (BMI), 21-32 kg/m(2)]. METHODS Volunteers underwent 10-min blood sampling to create 24-h ACTH concentration profiles. OUTCOMES Dynamic measures of ACTH secretion were studied. RESULTS Mean ACTH concentrations (R(2) = 0.15; P = 0.006) and both pulsatile (R(2) = 0.12; P = 0.018) and basal (nonpulsatile) (R(2) = 0.16; P = 0.005) ACTH secretion correlated directly with BMI (n = 48). Men had greater basal (P = 0.047), pulsatile (P = 0.031), and total (P = 0.010) 24-h ACTH secretion than women, including when total secretion was normalized for BMI (P = 0.019). In men, both ACTH-cortisol feedforward and cortisol-ACTH feedback asynchrony (cross-ApEn) increased with age (R(2) = 0.20 and 0.22; P = 0.021 and 0.018). ACTH spikiness rose with age (P = 0.046), principally in women. Irregularity of cortisol secretion (ApEn) increased with age (n = 48; P = 0.010), especially in men. In both sexes, percentage pulsatile ACTH secretion predicted 24-h mean cortisol concentrations (R(2) = 0.14; P = 0.009). CONCLUSION Valid comparisons of ultradian ACTH dynamics will require cohorts matched for age, gender, and BMI, conditions hitherto not satisfied in most physiological studies of this axis.
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Affiliation(s)
- Johannes D Veldhuis
- Endocrine Research Unit, Mayo Medical School, Mayo School of Graduate Medical Education, Center for Translational Science Activities, Mayo Clinic, Rochester, Minnesota 55905, USA.
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Roelfsema F, Pereira AM, Veldhuis JD, Adriaanse R, Endert E, Fliers E, Romijn JA. Thyrotropin secretion profiles are not different in men and women. J Clin Endocrinol Metab 2009; 94:3964-7. [PMID: 19773394 DOI: 10.1210/jc.2009-1155] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
CONTEXT The hypothalamo-pituitary-thyroid axis in women may differ from that in men. Previous reports have shown an almost 2-fold increased response to TRH in females compared with males. OBJECTIVE We analyzed TSH profiles in healthy men and women to delineate differences in the hypothalamo-pituitary-thyroid system. SUBJECTS AND INTERVENTION The subjects, 24 men (mean age 44 +/- 3 yr) and 22 women (mean age 42 +/- 3 yr) underwent a 24-h study with blood sampling intervals of 10 min. Premenopausal women were investigated in the early follicular phase of the cycle. METHODS Serum TSH concentration profiles were analyzed with a newly developed automated deconvolution program, approximate entropy, and cosinor regression. RESULTS Basal and pulsatile TSH secretion, and also pulse frequency, hormone half-lives, and secretory mode were indistinguishable in the two genders. There were no differences in diurnal variation, and the times of maximal secretion coincided. Approximate entropy, reflecting secretory regularity, was not different between men and women. In women but not men, TSH secretion was dependent linearly on age. CONCLUSIONS TSH secretion is gender invariant and depends on age in women only.
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Affiliation(s)
- Ferdinand Roelfsema
- Department of Endocrinology and Metabolic Diseases, Leiden University Medical Center, 2300 RC Leiden, The Netherlands.
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Veldhuis JD, Hudson SA, Bailey JN, Erickson D. Regulation of basal, pulsatile, and entropic (patterned) modes of GH secretion in a putatively low-somatostatin milieu in women. Am J Physiol Endocrinol Metab 2009; 297:E483-9. [PMID: 19491298 PMCID: PMC2724111 DOI: 10.1152/ajpendo.00136.2009] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Somatostatin (SS) released by hypothalamic neurons inhibits GH exocytosis noncompetitively. Therefore, we postulated that attenuation of GH feedback-induced SS outflow would help to unmask covariates of endogenous secretagogue drive. To this end, 42 healthy pre- and postmenopausal women were randomly assigned to receive leuprolide plus estradiol (E(2)) or leuprolide plus placebo. A putatively low-SS milieu was imposed by L-arginine infusion. Deconvolution and regularity analyses were applied to 6-h GH concentration-time profiles. By two-way ANOVA, age negatively (P < 0.001) and E(2) positively (P = 0.001) determined pulsatile GH secretion in the presumptively SS-deficient milieu (P < 0.001). Comparable effects were exerted on the mass of GH secreted per burst per unit distribution volume (age P = 0.001, E(2) P < 0.001, overall P < 0.001). E(2) alone predicted basal (nonpulsatile) GH secretion (P = 0.004). Stepwise forward-selection multivariate regression demonstrated that age (P = 0.0017) and E(2) (P = 0.0002) together explained 46% of intersubject variability in pulsatile GH secretion (P < 0.001) and fully replaced the negative univariate effect of abdominal visceral fat (r(2) = 0.32, P < 0.001). Moreover, age and E(2) (but not AVF) interacted to supervise GH regularity (P = 0.007). We conclude that age and E(2) availability individually and together constitute primary predictors of basal, pulsatile, and patterned GH secretion in an inferentially feedback-silenced context in healthy women. Therefore, both factors must be considered in framing hypotheses of endogenous GH drive.
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Affiliation(s)
- Johannes D Veldhuis
- Departments of Internal Medicine, Mayo Medical and Graduate Schools of Medicine, Mayo Clinic, Rochester, Minnesota 55905, USA.
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Roelfsema F, Kok P, Frolich M, Pereira AM, Pijl H. Disordered and increased adrenocorticotropin secretion with diminished adrenocorticotropin potency in obese in premenopausal women. J Clin Endocrinol Metab 2009; 94:2991-7. [PMID: 19454578 DOI: 10.1210/jc.2009-0350] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
CONTEXT The pituitary-adrenal ensemble of obese humans is marked by increased urinary excretion of cortisol and its metabolites in the face of normal circulating cortisol levels. For better understanding of the (patho) physiological meaning of these changes, the mechanistic underpinnings need to be clarified. INTERVENTION AND METHODS We investigated 17 obese women [body mass index (BMI) 30-39.4 kg/m(2)] and 14 normal women (BMI, 18.3-24.8 kg/m(2)) who underwent 24-h blood sampling at 10-min intervals, and plasma ACTH and cortisol concentrations were measured with sensitive assays. Data were analyzed with a new deconvolution program, approximate entropy (ApEn) analyses, and cosinor regression. OUTCOME ACTH and cortisol production rates were higher in obese women than in controls and correlated with BMI. Secretion of ACTH correlated with leptin (R = 0.63; P = 0.0001) and insulin (R = 0.67; P = 0.0001). ACTH ApEn and forward ACTH-cortisol cross-ApEn were diminished in obese women. The half-maximal effective concentration (ED(50)) of ACTH pulses vs. cortisol pulses was higher in obese women (38.3 +/- 4.9 vs. 25.1 +/- 3.7 ng/liter; P = 0.03), indicating decreased potency of ACTH. The diurnal properties of ACTH and cortisol secretion were unchanged in obese females. CONCLUSION Obese women exhibit enhanced ACTH and cortisol 24-h production compared with lean controls. The amplified ACTH drive is accompanied by decreased secretory regularity and diminished forward coupling between ACTH and cortisol. In addition, the potency of ACTH is decreased in obesity.
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Affiliation(s)
- Ferdinand Roelfsema
- Department of Endocrinology and Metabolic Diseases, Leiden University Medical Center, Albinusdreef 2, Leiden, The Netherlands.
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Roelfsema F, Biermasz NR, Frolich M, Keenan DM, Veldhuis JD, Romijn JA. Diminished and irregular thyrotropin secretion with preserved diurnal rhythm in patients with active acromegaly. J Clin Endocrinol Metab 2009; 94:1945-50. [PMID: 19336512 DOI: 10.1210/jc.2009-0174] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
CONTEXT The hypothalamo-pituitary-thyroid axis in acromegaly may be altered. Previous studies report diminished serum TSH concentrations in patients with active acromegaly and decreased response to TRH. On the other hand, most patients have normal thyroid hormone concentrations. OBJECTIVE Our aim was to analyze serum TSH profiles in relation to GH profiles in patients with untreated acromegaly, in order to delineate aberrations in the hypothalamo-pituitary-thyroid system. INTERVENTION Twenty-one patients with active acromegaly and matched controls underwent a 24-h, 10-min blood sampling study. GH and TSH data were analyzed with a newly developed automated deconvolution program, approximate entropy, and cosinor regression. RESULTS Basal (10.4 +/- 2.0 vs. 13.8 +/- 1.4 mU/liter . 24 h; P = 0.02) and pulsatile (11.4 +/- 1.7 vs. 18.6 +/- 1.6 mU/liter . 24 h; P = 0.002) TSH secretion was decreased in patients. TSH secretory regularity was diminished with loss of pattern synchrony between TSH and GH. Total TSH secretion correlated with TSH increase after TRH (R = 0.75; P = 0.0001), negatively with the log-transformed GH secretion rate (R = -0.52; P = 0.001), but not with adenoma size. The diurnal TSH rhythm was preserved. Total and free T4 concentrations were similar in patients and controls. CONCLUSION Basal and pulsatile TSH secretion is decreased in active acromegaly, although T4 levels are unaffected. Diminished TSH secretion is compatible with enhanced restraint by tumoral GH feedback-driven somatostatin outflow, explaining also the reduced regularity of TSH secretion. Unchanged T4 concentrations might reflect decreased sympathetic function in GH excess states, heightening responsiveness of the thyroid gland to TSH.
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Affiliation(s)
- Ferdinand Roelfsema
- Leiden University Medical Center, Department of Endocrinology and Metabolic Diseases, P.O. Box 9600, Leiden 2300 RC, The Netherlands.
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Kok P, Roelfsema F, Frölich M, van Pelt J, Meinders AE, Pijl H. Bromocriptine reduces augmented thyrotropin secretion in obese premenopausal women. J Clin Endocrinol Metab 2009; 94:1176-81. [PMID: 19190107 DOI: 10.1210/jc.2008-2303] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
CONTEXT Diurnal TSH secretion is enhanced in obese premenopausal women. Dopamine inhibits TSH secretion through activation of dopamine D(2) receptors (D(2)R). Dopamine D(2)R availability in the brain is reduced in obese humans in proportion to body adiposity. We hypothesized that deficient dopamine D(2)R signaling is involved in the enhanced TSH secretion associated with obesity. OBJECTIVE The effect of short-term bromocriptine treatment on spontaneous TSH secretion in obese women was studied while body weight and caloric intake remained constant. DESIGN AND SETTING We conducted a prospective, fixed-order, crossover study in a Clinical Research Center. PARTICIPANTS Seventeen obese women (body mass index, 33.2 +/- 0.6 kg/m(2)) were studied twice in the early follicular phase of their menstrual cycle. INTERVENTION Subjects were treated for 8 d with placebo and bromocriptine. MAIN OUTCOME MEASURE(S) Blood was collected for 24 h at 10-min intervals, and TSH and leptin were analyzed with deconvolution and correlation techniques, approximate entropy, and cosine regression. RESULTS Bromocriptine reduced 24-h TSH secretion (placebo, 29.8 +/- 4.6 mU/liter . 24 h, vs. bromocriptine, 22.4 +/- 3.7 mU/liter . 24 h; P = 0.001), whereas free T(4) and total T(3) concentrations did not change. Bromocriptine administration reduced the mesor and amplitude of the 24-h rhythm without resetting the phase. The regularity of the subordinate TSH pattern and synchrony between leptin and TSH were unaffected by bromocriptine. CONCLUSION Activation of dopamine D(2)R by bromocriptine reverses enhanced diurnal TSH secretion in obese women. Thus, reduced dopaminergic neuronal signaling might be involved in the perturbation of the thyrotrope hormonal axis in obese premenopausal women.
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Affiliation(s)
- Petra Kok
- Department of Endocrinology and Metabolic Diseases, Leiden University Medical Center, Leiden, The Netherlands
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Veldhuis JD, Keenan DM, Liu PY, Iranmanesh A, Takahashi PY, Nehra AX. The aging male hypothalamic-pituitary-gonadal axis: pulsatility and feedback. Mol Cell Endocrinol 2009; 299:14-22. [PMID: 18838102 PMCID: PMC2662347 DOI: 10.1016/j.mce.2008.09.005] [Citation(s) in RCA: 67] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/24/2007] [Revised: 09/02/2008] [Accepted: 09/04/2008] [Indexed: 11/29/2022]
Abstract
Aging results in insidious decremental changes in hypothalamic, pituitary and gonadal function. The foregoing three main anatomic loci of control are regulated by intermittent time-delayed signal exchange, principally via gonadotropin-releasing hormone (GnRH), luteinizing hormone (LH) and testosterone/estradiol (Te/E(2)). A mathematical framework is required to embody these dynamics. The present review highlights integrative adaptations in the aging male hypothalamic-pituitary-gonadal axis, as assessed by recent objective ensemble models of the axis as a whole.
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Affiliation(s)
- Johannes D Veldhuis
- Endocrine Research Unit, Department of Internal Medicine, Mayo Clinic College of Medicine, Mayo Clinic, 200 First Steet SW, Rochester, MN 55905, United States.
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Roelfsema F, Kok S, Kok P, Pereira AM, Biermasz NR, Smit JW, Frolich M, Keenan DM, Veldhuis JD, Romijn JA. Pituitary-hormone secretion by thyrotropinomas. Pituitary 2009; 12:200-10. [PMID: 19051037 PMCID: PMC2712623 DOI: 10.1007/s11102-008-0159-6] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Hormone secretion by somatotropinomas, corticotropinomas and prolactinomas exhibits increased pulse frequency, basal and pulsatile secretion, accompanied by greater disorderliness. Increased concentrations of growth hormone (GH) or prolactin (PRL) are observed in about 30% of thyrotropinomas leading to acromegaly or disturbed sexual functions beyond thyrotropin (TSH)-induced hyperthyroidism. Regulation of non-TSH pituitary hormones in this context is not well understood. We there therefore evaluated TSH, GH and PRL secretion in 6 patients with up-to-date analytical and mathematical tools by 24-h blood sampling at 10-min intervals in a clinical research laboratory. The profiles were analyzed with a new deconvolution method, approximate entropy, cross-approximate entropy, cross-correlation and cosinor regression. TSH burst frequency and basal and pulsatile secretion were increased in patients compared with controls. TSH secretion patterns in patients were more irregular, but the diurnal rhythm was preserved at a higher mean with a 2.5 h phase delay. Although only one patient had clinical acromegaly, GH secretion and IGF-I levels were increased in two other patients and all three had a significant cross-correlation between the GH and TSH. PRL secretion was increased in one patient, but all patients had a significant cross-correlation with TSH and showed decreased PRL regularity. Cross-ApEn synchrony between TSH and GH did not differ between patients and controls, but TSH and PRL synchrony was reduced in patients. We conclude that TSH secretion by thyrotropinomas shares many characteristics of other pituitary hormone-secreting adenomas. In addition, abnormalities in GH and PRL secretion exist ranging from decreased (joint) regularity to overt hypersecretion, although not always clinically obvious, suggesting tumoral transformation of thyrotrope lineage cells.
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Affiliation(s)
- Ferdinand Roelfsema
- Department of Endocrinology and Metabolic Diseases, Leiden University Medical Center, Albinusdreef 2 NL2333ZA, Leiden, The Netherlands.
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Veldhuis JD, Keenan DM, Bailey JN, Adeniji A, Miles JM, Paulo R, Cosma M, Soares-Welch C. Testosterone supplementation in older men restrains insulin-like growth factor's dose-dependent feedback inhibition of pulsatile growth hormone secretion. J Clin Endocrinol Metab 2009; 94:246-54. [PMID: 18984660 PMCID: PMC2630862 DOI: 10.1210/jc.2008-1516] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
BACKGROUND Pulsatile GH secretion declines in older men. The causal mechanisms are unknown. Candidates include deficient feedforward (stimulation) by endogenous secretagogues and excessive feedback (inhibition) by GH or IGF-I due to age and/or relative hypoandrogenemia. HYPOTHESIS Testosterone (T) supplementation in healthy older men will restrain negative feedback by systemic concentrations of IGF-I. SUBJECTS Twenty-four healthy men (ages, 50 to 75 yr; body mass index, 24 to 30 kg/m(2)) participated in the study. METHODS We performed a prospectively randomized, double-blind, placebo-controlled assessment of the impact of pharmacological T supplementation on GH responses to randomly ordered separate-day injections of recombinant human IGF-I doses of 0, 1.0, 1.5, and 2.0 mg/m(2). ANALYSIS Deconvolution and approximate entropy analyses of pulsatile, basal, and entropic (pattern-sensitive) modes of GH secretion were conducted. RESULTS Recombinant human IGF-I injections 1) elevated mean and peak serum IGF-I concentrations dose-dependently (both P < 0.001); 2) suppressed pulsatile GH secretion (P = 0.003), burst mass (P = 0.025), burst number (P = 0.005), interpulse variability (P = 0.032), and basal GH secretion (P = 0.009); and 3) increased secretory pattern regularity (P = 0.020). T administration did not alter experimentally controlled IGF-I concentrations, but it elevated mean GH concentrations (P = 0.015) and stimulated pulsatile GH secretion (frequency P = 0.037, mass per burst P = 0.038). Compared with placebo, T attenuated exogenous IGF-I's inhibition of GH secretory-burst mass (P < 0.038) without restoring pulse number, basal secretion, or pattern regularity. CONCLUSION The capability of systemic T to mute IGF-I feedback on pulsatile GH secretion suggests a novel mechanism for augmenting GH production.
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Affiliation(s)
- Johannes D Veldhuis
- Department of Medicine, Endocrine Research Unit, Mayo School of Graduate Medical Education, Clinical Translational Science Center, Mayo Clinic, Rochester, Minnesota 55905, USA.
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Veldhuis JD, Keenan DM, Pincus SM. Motivations and methods for analyzing pulsatile hormone secretion. Endocr Rev 2008; 29:823-64. [PMID: 18940916 PMCID: PMC2647703 DOI: 10.1210/er.2008-0005] [Citation(s) in RCA: 156] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/20/2008] [Accepted: 09/16/2008] [Indexed: 01/05/2023]
Abstract
Endocrine glands communicate with remote target cells via a mixture of continuous and intermittent signal exchange. Continuous signaling allows slowly varying control, whereas intermittency permits large rapid adjustments. The control systems that mediate such homeostatic corrections operate in a species-, gender-, age-, and context-selective fashion. Significant progress has been made in understanding mechanisms of adaptive interglandular signaling in vivo. Principal goals are to understand the physiological origins, significance, and mechanisms of pulsatile hormone secretion. Key analytical issues are: 1) to quantify the number, size, shape, and uniformity of pulses, nonpulsatile (basal) secretion, and elimination kinetics; 2) to evaluate regulation of the axis as a whole; and 3) to reconstruct dose-response interactions without disrupting hormone connections. This review will focus on the motivations driving and the methodologies used for such analyses.
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Affiliation(s)
- Johannes D Veldhuis
- Endocrine Research Unit, Department of Internal Medicine, Mayo Medical School, Mayo School of Graduate Medical Education, Center for Translational Science Activities, Mayo Clinic, Rochester, Minnesota 55905, USA.
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Veldhuis JD, Keenan DM, Bailey JN, Adeniji A, Miles JM, Paulo R, Cosma M, Soares-Welch C. Estradiol supplementation in postmenopausal women attenuates suppression of pulsatile growth hormone secretion by recombinant human insulin-like growth factor type I. J Clin Endocrinol Metab 2008; 93:4471-8. [PMID: 18728158 PMCID: PMC2582567 DOI: 10.1210/jc.2008-1493] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
BACKGROUND Why pulsatile GH secretion declines in estrogen-deficient postmenopausal individuals remains unknown. One possibility is that estrogen not only enhances stimulation by secretagogues but also attenuates negative feedback by systemic IGF-I. SITE: The study took place at an academic medical center. SUBJECTS Subjects were healthy postmenopausal women (n=25). METHODS The study included randomized assignment to estradiol (n=13) or placebo (n=12) administration for 16 d and randomly ordered administration of 0, 1.0, 1.5, and 2.0 mg/m2 recombinant human IGF-I sc on separate days fasting. ANALYSIS Deconvolution analysis of pulsatile and basal GH secretion and approximate entropy (pattern-regularity) analysis were done to quantify feedback effects of IGF-I. OUTCOMES Recombinant human IGF-I injections increased mean and peak serum IGF-I concentrations dose dependently (P<0.001) and suppressed mean GH concentrations (P<0.001), pulsatile GH secretion (P=0.001), and approximate entropy (P<0.001). Decreased GH secretion was due to reduced secretory-burst mass (P=0.005) and frequency (P<0.001) but not basal GH release (P=0.52). Estradiol supplementation lowered endogenous, but did not alter infused, IGF-I concentrations while elevating mean GH concentrations (P=0.012) and stimulating pulsatile (P=0.008) and basal (P<0.001) GH secretion. Estrogen attenuated IGF-I's inhibition of pulsatile GH secretion (P=0.042) but was unable to restore physiological GH pulse frequency or normalize approximate entropy. CONCLUSION Short-term estrogen replacement in postmenopausal women selectively mutes IGF-I-mediated feedback on pulsatile GH secretion. Disinhibition of negative feedback thus confers a novel mechanism by which estrogen may obviate hyposomatotropism.
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Affiliation(s)
- Johannes D Veldhuis
- Department of Medicine, Mayo School of Graduate Medical Education, Clinical Translational Science Center, Mayo Clinic, Rochester, Minnesota 55905, USA.
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Iranmanesh A, Veldhuis JD. Hypocortisolemic clamp unmasks jointly feedforward- and feedback-dependent control of overnight ACTH secretion. Eur J Endocrinol 2008; 159:561-8. [PMID: 18713842 PMCID: PMC2693721 DOI: 10.1530/eje-08-0417] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
BACKGROUND ACTH secretion is under hypothalamic stimulatory (feedforward) and adrenal inhibitory (feedback) control. HYPOTHESIS Assessment of overnight ACTH secretion during a hypocortisolemic clamp will permit the estimation of changing feedforward and feedback. SUBJECTS Seven healthy men. INTERVENTIONS An oral dose of placebo (PLAC), metyrapone (METY, 3 g), or ketoconazole (KTCZ, 1.2 g) was given at midnight (MN) to block glucocorticoid synthesis. Plasma ACTH was sampled every 10 min (MN to 0800 h). ANALYSIS Variable-waveform deconvolution analysis of ACTH secretion and approximate entropy (ApEn) analysis of pattern regularity. RESULTS Compared with PLAC, administration of METY and KTCZ reduced morning cortisol concentrations by >or=77 and 54% respectively (P<0.001). Hypocortisolemia elevated pulsatile ACTH secretion by 8.2- (METY) and 5.3-fold (KTCZ; both P<0.001). Basal ACTH secretion rose by 3.4-fold under METY-induced cortisol depletion (P=0.020). ACTH secretory-burst shape and half-life were stable. ApEn of ACTH release declined overnight (P=0.021) and with the drug (P=0.001), denoting enhanced feedforward coordination. CONCLUSION The combined data predict overnight amplification and coordination of hypothalamic feedforward drive onto ACTH release. Therefore, disruption of either mechanism might contribute to clinical pathophysiology, such as late-day elevations of cortisol output in fasting, alcoholism, depression, or aging.
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Affiliation(s)
- Ali Iranmanesh
- Department of Medicine, Salem Veterans Affairs Medical Center, Salem, Virginia 24153, USA
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Roelfsema F, Pereira AM, Keenan DM, Veldhuis JD, Romijn JA. Thyrotropin secretion by thyrotropinomas is characterized by increased pulse frequency, delayed diurnal rhythm, enhanced basal secretion, spikiness, and disorderliness. J Clin Endocrinol Metab 2008; 93:4052-7. [PMID: 18682501 DOI: 10.1210/jc.2008-1145] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
CONTEXT Hormone secretion by somatotropinomas, corticotropinomas, and prolactinomas exhibits increased pulsatility and basal secretion, accompanied by greater disorderliness. OBJECTIVE Our objective was to evaluate TSH secretion by thyrotropinomas with up-to-date analytical and mathematical tools. DESIGN Twenty-four hour blood samplings at 10-min intervals in a clinical research laboratory in five patients with a thyrotropinoma and 10 healthy age- and gender-matched controls were performed. The obtained serum TSH profiles were analyzed with a new deconvolution method, approximate entropy, Cosinor analysis, and by quantification of spikiness. RESULTS TSH burst frequency and basal secretion were increased in patients compared with controls. TSH secretion patterns in patients were more irregular than in controls, but the diurnal rhythm was preserved at a higher mean in all patients, although with a 2-h phase delay. CONCLUSION TSH secretion by thyrotropinomas shares many characteristics with other pituitary hormone-secreting adenomas.
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Affiliation(s)
- Ferdinand Roelfsema
- Department of Endocrinology and Metabolism, Leiden University Medical Center, Albinusdreef 2, NL2333ZA Leiden, The Netherlands.
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Veldhuis JD, Reynolds GA, Iranmanesh A, Bowers CY. Twenty-four hour continuous ghrelin infusion augments physiologically pulsatile, nycthemeral, and entropic (feedback-regulated) modes of growth hormone secretion. J Clin Endocrinol Metab 2008; 93:3597-603. [PMID: 18593763 PMCID: PMC2567861 DOI: 10.1210/jc.2008-0620] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
BACKGROUND Ghrelin is a 28-amino acid acylated peptide that potentiates GHRH stimulation and opposes somatostatin inhibition acutely. Whether prolonged ghrelin administration can sustain physiological patterns of GH secretion remains unknown. HYPOTHESIS Continuous delivery of ghrelin will amplify physiological patterns of GH secretion over 24 h. SUBJECTS Men and women ages 29-69 yr, body mass indices 23-52 kg/m2, were included in the study. LOCATION The study was performed at an academic medical center. METHODS Twenty-four hour continuous sc infusion of saline vs. ghrelin (1 microg/kg.h) with frequent sampling was examined. Deconvolution and entropy analyses were performed. OUTCOMES IGF-I concentrations were determined. Basal, pulsatile, nycthemeral, and entropic measures of GH secretion were calculated. RESULTS Ghrelin infusion compared with saline infusion for 24 h elevated (median) acylated ghrelin, GH, and IGF-I concentrations by 8.1-fold (P < 0.001),11-fold (P < 0.001), and 1.4-fold (P = 0.002). GH secretory-burst mass and frequency increased by 6.6-fold (P = 0.004) and 1.7-fold (P < 0.001), respectively, resulting in a 12-fold increase in pulsatile GH secretion (P < 0.001). Interpulse variability decreased significantly (P = 0.046), whereas GH secretory-burst shape and half-life did not change. The amplitude of the nycthemeral GH rhythm increased by 3.4-fold (P < 0.001), and GH patterns became more irregular (higher approximate entropy P < 0.001). Combining GHRH with ghrelin was not an additive in driving GH secretion. CONCLUSIONS Continuous ghrelin infusion for 24 h elevates acylated ghrelin, GH and IGF-I concentrations, and stimulates pulsatile, nycthemeral, and entropic modes of GH secretion. The consistency of outcomes in a heterogeneous cohort of adults suggests potentially broad utility of this physiological secretagogue in hyposomatotropic states.
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Affiliation(s)
- Johannes D Veldhuis
- Endocrine Research Unit, Department of Internal Medicine, Clinical Translational Science Unit, Mayo Medical and Graduate Schools of Medicine, Mayo Clinic, Rochester, Minnesota 55905, USA.
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Kok P, Roelfsema F, Frölich M, van Pelt J, Meinders AE, Pijl H. Short-term treatment with bromocriptine improves impaired circadian growth hormone secretion in obese premenopausal women. J Clin Endocrinol Metab 2008; 93:3455-61. [PMID: 18559918 DOI: 10.1210/jc.2008-0001] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
CONTEXT A profound reduction of spontaneous as well as stimulated GH secretion has been consistently observed in obesity. Dopamine promotes GH release through activation of dopamine D2 receptors (D2Rs). Dopamine D2R availability in the brain is reduced in obese humans in proportion to body adiposity. We hypothesized that impaired dopamine D2R signaling is mechanistically involved in the deficient GH secretion associated with obesity. OBJECTIVE To test this hypothesis, we studied the effect of short-term bromocriptine (B) (a D2R agonist) treatment on spontaneous 24-h GH secretion in obese women, while body weight and caloric intake remained constant. DESIGN This was a prospective, fixed order, cross-over study. SETTING The study was performed in the Clinical Research Center at Leiden University Medical Center. PARTICIPANTS There were 18 healthy obese women (body mass index 33.2 +/- 0.6 kg/m2) studied twice in the early follicular phase of their menstrual cycle. INTERVENTION(S) Eight days of treatment with B and placebo (Pl) was performed. MAIN OUTCOME MEASURE(S) Blood was collected during 24 h at 10-min intervals for determination of GH concentrations. GH secretion parameters were calculated using deconvolution analysis. RESULTS Short-term treatment with B significantly enhanced diurnal GH secretion (Pl 121.4 +/- 16.4 vs. B 155.4 +/- 15.2 microg/liter(volume of distribution).24 h; P = 0.01), whereas IGF-I concentrations remained constant (Pl 22.4 +/- 2.4 vs. B 21.8 +/- 1.6 nmol/liter; P = 0.928). CONCLUSIONS Activation of dopamine D2Rs by B favorably affects impaired nyctohemeral GH secretion in obese women. Reduced dopaminergic neuronal signaling might be involved in the pathogenesis of obesity associated hyposomatotropism.
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Affiliation(s)
- Petra Kok
- Department of General Internal Medicine, Leiden University Medical Center, RC Leiden, The Netherlands
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Krieg RJ, Veldhuis JD, Thornhill BA, Chevalier RL, Gil G. Growth hormone (GH) secretion, GH-dependent gene expression, and sexually dimorphic body growth in young rats with chronic renal failure. Endocrine 2008; 33:323-30. [PMID: 19016354 DOI: 10.1007/s12020-008-9094-6] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/18/2008] [Accepted: 06/27/2008] [Indexed: 11/28/2022]
Abstract
Chronic renal disease results in growth failure in children. This study sought to determine the influences of early renal failure on body growth, growth hormone (GH) secretion, and GH-dependent hepatic gene expression. Neonatal animals were subjected to five-sixth nephrectomy (Nephr) and monitored during growth. Sham-operated male (Sham) and female (Fem) rats served as controls. Whereas Nephr of adult animals causes renal insufficiency, neonatal nephrectomy leads to frank renal failure. In male Nephr compared with Sham animals, GH half-life and GH pulse frequency increased by 1.55- and 1.33-fold, respectively, and GH secretory-burst size decreased by 80%. Approximate entropy analysis quantified more disorderly patterns of GH secretion in Nephr animals, which differed from Sham males, but not from Fem rats. Expression of liver P450 CYP2C11 mRNA, which is dependent upon the male GH pattern, became undetectable, whereas expression of liver P450 CYP2C12 mRNA, which is dependent upon the female GH pattern, increased multifold. Renal failure in young rats abrogates the male pattern of GH pulsatility, abolishes the sexual dimorphism of body weight gain, and induces a female pattern of hepatic gene expression. These data raise the possibility that disruption of pulsatile GH secretion contributes to the growth failure of renal disease.
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Affiliation(s)
- Richard J Krieg
- Department of Anatomy and Neurobiology, Medical College of Virginia Campus, Virginia Commonwealth University, P.O. Box 980709, Richmond, VA 23298-0709, USA.
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Aksglaede L, Jensen RB, Carlsen E, Kok P, Keenan DM, Veldhuis J, Skakkebaek NE, Juul A. Increased basal and pulsatile secretion of FSH and LH in young men with 47,XXY or 46,XX karyotypes. Eur J Endocrinol 2008; 158:803-10. [PMID: 18322303 PMCID: PMC2729082 DOI: 10.1530/eje-07-0709] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
OBJECTIVE The regulation of normal sexual maturation and reproductive function is dependent on a precise hormonal regulation at hypothalamic, pituitary, and gonadal levels. The aim of this study was to investigate the neuroendocrine integrity of the pituitary-gonadal axis in patients with primary testicular failure due to supernumerary X chromosomes. DESIGN Cross-sectional study. METHODS In this study, 7 untreated patients with primary gonadal insufficiency due to SRY-positive 46,XX (n=4) and 46,XXY karyotypes (n=3) aged 18.8 years and 25 age-matched healthy controls participated. Reproductive hormones, testicular size, and overnight LH and FSH serum profiles and overnight urine LH and FSH excretion were determined. RESULTS Basal LH and FSH secretion was elevated 6.3- and 25.4-fold respectively in the patients and the amount of LH and FSH secreted per burst were 2.0- and 6.6-fold elevated. We found significantly more LH but not FSH peaks per 24 h, as estimated by the Weibull lambda analysis. There was no difference between approximate entropy ratios or Weibull gamma analyses indicating comparable orderliness and regularity of LH and FSH secretion. Overnight urinary LH and FSH excretion was significantly elevated in patients compared with controls and correlated significantly with calculated total overnight LH and FSH secretion respectively, thus validating deconvolution. CONCLUSION In this group of patients with severe hypergonadotropic hypogonadism due to a supernumerary X chromosome, higher basal, pulsatile, and total LH and FSH secretion were associated with significantly more LH peaks per 24 h in comparison with healthy controls. Thus, our data indicate that in patients with Klinefelter syndrome and XX male karyotypes the entire hypothalamic-pituitary-gonadal axis has undergone functional changes.
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Affiliation(s)
- Lise Aksglaede
- University Department of Growth and Reproduction GR, Rigshospitalet, University of Copenhagen, Section 5064, Blegdamsvej 9, DK-2100 Copenhagen Ø, Denmark.
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Michalaki M, Kyriazopoulou V, Mylonas P, Argentou MI, Debaveye Y, Kalfarentzos F, Vagenakis AG. Glucose Levels and Insulin Secretion in Surgery-Induced Hyperglycemia in Normoglycemic Obese Patients. Obes Surg 2008; 18:1460-6. [DOI: 10.1007/s11695-008-9501-3] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2008] [Accepted: 03/10/2008] [Indexed: 11/29/2022]
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Liu PY, Iranmanesh A, Keenan DM, Pincus SM, Veldhuis JD. A noninvasive measure of negative-feedback strength, approximate entropy, unmasks strong diurnal variations in the regularity of LH secretion. Am J Physiol Endocrinol Metab 2007; 293:E1409-15. [PMID: 17848633 DOI: 10.1152/ajpendo.00365.2007] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The secretion of anterior-pituitary hormones is subject to negative feedback. Whether negative feedback evolves dynamically over 24 h is not known. Conventional experimental paradigms to test this concept may induce artifacts due to nonphysiological feedback. These limitations might be overcome by a noninvasive methodology to quantify negative feedback continuously over 24 h without disrupting the axis. The present study exploits a recently validated model-free regularity statistic, approximate entropy (ApEn), which monitors feedback changes with high sensitivity and specificity (both >90%; Pincus SM, Hartman ML, Roelfsema F, Thorner MO, Veldhuis JD. Am J Physiol Endocrinol Metab 273: E948-E957, 1999). A time-incremented moving window of ApEn was applied to LH time series obtained by intensive (10-min) blood sampling for four consecutive days (577 successive measurements) in each of eight healthy men. Analyses unveiled marked 24-h variations in ApEn with daily maxima (lowest feedback) at 1100 +/- 1.7 h (mean +/- SE) and minima (highest feedback) at 0430 +/- 1.9 h. The mean difference between maximal and minimal 24-h LH ApEn was 0.348 +/- 0.018, which differed by P < 0.001 from all three of randomly shuffled versions of the same LH time series, simulated pulsatile data and assay noise. Analyses artificially limited to 24-h rather than 96-h data yielded reproducibility coefficients of 3.7-9.0% for ApEn maxima and minima. In conclusion, a feedback-sensitive regularity statistic unmasks strong and consistent 24-h rhythmicity of the orderliness of unperturbed pituitary-hormone secretion. These outcomes suggest that ApEn may have general utility in probing dynamic mechanisms mediating feedback in other endocrine systems.
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Affiliation(s)
- Peter Y Liu
- Endocrine Research Unit, Mayo School of Graduate Medical Education, General Clinical Research Center, Mayo Clinic, Rochester, MN 55905, USA
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van der Klaauw AA, Pereira AM, van Thiel SW, Frolich M, Iranmanesh A, Veldhuis JD, Roelfsema F, Romijn JA. Attenuated pulse size, disorderly growth hormone and prolactin secretion with preserved nyctohemeral rhythm distinguish irradiated from surgically treated acromegaly patients. Clin Endocrinol (Oxf) 2007; 66:489-98. [PMID: 17371464 DOI: 10.1111/j.1365-2265.2006.02757.x] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
BACKGROUND Radiation induces time-dependent loss of anterior pituitary function, attributed to damage of the pituitary gland and hypothalamic centres. The development of growth hormone deficiency (GHD) in irradiated acromegaly patients is not well defined. OBJECTIVE Detailed analysis of spontaneous 24-h GH and prolactin (PRL) secretion in relation to other pituitary functions and serum IGF-I concentrations in an attempt to find criteria for GHD in acromegalic patients with a GH response < 3 microg/l during the insulin tolerance test (ITT). DESIGN Plasma hormone profiles obtained by 10 min sampling for 24 h in postoperatively irradiated acromegalic patients, compared with patients cured by surgery only and matched healthy controls. SETTING/PARTICIPANTS University setting. Fifteen subjects in each group. OUTCOME MEASURES GH and PRL secretory parameters quantified by deconvolution, cluster, cosinor and approximate entropy (ApEn) analyses, IGF-I concentrations. RESULTS Irradiation attenuated pulsatile secretion of GH and PRL, but total PRL secretion was unchanged. GH and PRL secretory regularity were diminished. Circadian timing remained intact. Pulsatile GH secretion and IGF-I were correlated (R = 0.30, P = 0.04). Criteria of pulsatile GH secretion = 12 microg/l/24 h and ApEn = 0.800 separated 12 of 15 irradiated patients from all others. CONCLUSION Irradiated acromegaly patients with a subnormal GH response to ITT have very limited spontaneous GH secretion, with specific attenuation of the size of GH bursts and a highly irregular pattern, but with retained diurnal properties. These patients are thus likely GH-deficient and might benefit from GH replacement.
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Affiliation(s)
- A A van der Klaauw
- Department of Endocrinology and Metabolic Diseases, Leiden University Medical Center, Leiden, the Netherlands
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Farhy LS, Bowers CY, Veldhuis JD. Model-projected mechanistic bases for sex differences in growth hormone regulation in humans. Am J Physiol Regul Integr Comp Physiol 2007; 292:R1577-93. [PMID: 17185408 DOI: 10.1152/ajpregu.00584.2006] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Models of physiological systems facilitate rational experimental design, inference, and prediction. A recent construct of regulated growth hormone (GH) secretion interlinks the actions of GH-releasing hormone (GHRH), somatostatin (SRIF), and GH secretagogues (GHS) with GH feedback in the rat (Farhy LS, Veldhuis JD. Am J Physiol Regul Integr Comp Physiol 288: R1649–R1663, 2005). In contrast, no comparable formalism exists to explicate GH dynamics in any other species. The present analyses explore whether a unifying model structure can represent species- and sex-defined distinctions in the human and rodent. The consensus principle that GHRH and GHS synergize in vivo but not in vitro was explicable by assuming that GHS 1) evokes GHRH release from the brain, 2) opposes inhibition by SRIF both in the hypothalamus and on the pituitary gland, and 3) stimulates pituitary GH release directly and additively with GHRH. The gender-selective principle that GH pulses are larger and more irregular in women than men was conferrable by way of 4) higher GHRH potency and 5) greater GHS efficacy. The overall construct predicts GHRH/GHS synergy in the human only in the presence of SRIF when the brain-pituitary nexus is intact, larger and more irregular GH pulses in women, and observed gender differences in feedback by GH and the single and paired actions of GHRH, GHS, and SRIF. The proposed model platform should enhance the framing and interpretation of novel clinical hypotheses and create a basis for interspecies generalization of GH-axis regulation.
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Affiliation(s)
- Leon S Farhy
- Division of Endocrinology and Metabolism, Department of Internal Medicine, School of Medicine, University of Virginia, Charlottesville, Virginia, USA
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