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Jansson D, Lindberg AS, Lundberg E, Domellöf M, Theos A. Effects of Resistance and Endurance Training Alone or Combined on Hormonal Adaptations and Cytokines in Healthy Children and Adolescents: A Systematic Review and Meta-analysis. SPORTS MEDICINE - OPEN 2022; 8:81. [PMID: 35727479 PMCID: PMC9213633 DOI: 10.1186/s40798-022-00471-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/28/2021] [Accepted: 06/05/2022] [Indexed: 12/02/2022]
Abstract
Background No previous systematic review has quantitatively compared the effects of resistance training, endurance training, or concurrent training on hormonal adaptations in children and adolescents. Objective was to examine the effects of exercise training and training type on hormonal adaptations in children and adolescents. Methods A systematic literature search was conducted in the following databases: PubMed, Web of Science, and EBSCO. Eligibility criteria were: population: healthy youth population sample (mean age < 18 years); intervention: resistance training, endurance training, or concurrent training (> 4 weeks duration); comparison: control group; outcome: pre- and post-levels of hormones and cytokines; and study design: randomized and non-randomized controlled trials. We used a random-effect model for the meta-analysis. The raw mean difference in hormones from baseline to post-intervention was presented alongside 95% confidence intervals (CI). Further, the certainty of evidence quality and the risk of bias were assessed. Results A total of 3689 records were identified, of which 14 studies were eligible for inclusion. Most studies examined adolescents with fewer studies on children (age < 12 years, N = 5 studies) and females (N = 2 studies). Nine exercise training programs used endurance training, five studies used resistance training, and no eligible study used concurrent training. The meta-analysis showed no significant effect of exercise training on testosterone (MD = 0.84 nmol/L), cortisol (MD = − 17.4 nmol/L), or SHBG (MD = − 5.58 nmol/L). Subgroup analysis showed that resistance training significantly increased testosterone levels after training (MD = 3.42 nmol/L) which was not observed after endurance training (MD = − 0.01 nmol/L). No other outcome differed between training types. Exercise training resulted in small and non-significant changes in GH (MD = 0.48 ng/mL, p = 0.06) and IGF-I (MD = − 22.90 ng/mL, p = 0.07). GH response to endurance training may be age-dependent and evident in adolescents (MD = 0.59 ng/mL, p = 0.04) but not when children and adolescents are pooled (MD = 0.48 ng/mL, p = 0.06). Limited evidence exists to conclude on IL-6 and TNF-α effects of exercise training. Assessments of GRADE domains (risk of bias, consistency, directness, or precision of the findings) revealed serious weaknesses with most of the included outcomes (hormones and cytokines). Conclusions This systematic review suggests that exercise training has small effects on hormonal concentrations in children and adolescents. Changes in testosterone concentrations with training are evident after resistance training but not endurance training. GH's response to training may be affected by maturation and evident in adolescents but not children. Further high-quality, robust training studies on the effect of resistance training, endurance training, and concurrent training are warranted to compare their training-specific effects. Registration: PROSPERO: CRD42021241130.
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Ramadan W, Elsayed A, Alim MA, Abdi E, Razek MKA. The Influence of Ballistic Exercises on Growth, Somatomedin Hormones for Soccer Players. Open Access Maced J Med Sci 2022. [DOI: 10.3889/oamjms.2022.9122] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022] Open
Abstract
BACKGROUND: The sequence of exercise-induced hormonal changes demonstrates the quantification of training and competition loads and developing a sport-specific conditioning program.
AIM: The present study investigates the impact of ballistic exercises on biochemical variables and the muscular ability of soccer players.
METHODS: Participants were assigned randomly to two groups, including ten participants in each group, and underwent a pre- post-intervention test, including growth hormone, somatomedin hormone, triple jump, and wide jump.
RESULTS: The experimental group showed a significant increase in Growth by 43.56%, somatomedin by 6.99%, Triple jumps by 18.65%, and Wide jump by 15.68% compared to the control group.
CONCLUSION: In conclusion, ballistic exercises improved growth and somatomedin hormone, triple jump, and wide jump and thus enhancing biochemical variables and muscular ability.
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Leng L, Xing Y, Liang Y, Wang C, Ma H. Relationship between circulating insulin-like growth factor-1 and blood pressure in adults: A systematic review and meta-analysis of observational studies. Growth Horm IGF Res 2021; 60-61:101416. [PMID: 34273744 DOI: 10.1016/j.ghir.2021.101416] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/16/2021] [Revised: 06/16/2021] [Accepted: 06/21/2021] [Indexed: 11/16/2022]
Abstract
OBJECTIVE Insulin-like growth factor 1 (IGF-1) is an important factor related to cardiovascular disease. In recent years, studies have shown the involvement of IGF-1 and blood pressure (BP). Nevertheless, the results were inconsistent. Thus, the purpose of this study was to systematically evaluate the associations of circulating IGF-1 levels with BP in adults. METHODS Two reviewers independently searched and screened articles from the Pubmed, EMBASE, Cochrane Library, CNKI, and WANFANG databases up to May 2020. A total of 12 studies that reported the correlation coefficients between IGF-1, systolic blood pressure (SBP), and diastolic blood pressure (DBP) were included. RESULTS IGF-1 was significantly correlated with SBP [r = -0.15; 95% CI = -0.21, -0.08; P < 0.0001] and DBP [r = -0.10; 95% CI = -0.16, -0.05; P = 0.0004]. Subgroup analysis further revealed that the relationship between IGF-1 and BP was influenced by race and age. CONCLUSION Circulating IGF-1 was negatively correlated with SBP and DBP. Further researches are necessary to explore the pathogenesis of this relationship and to evaluate the role of IGF-1 in the treatment of hypertension.
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Affiliation(s)
- Lina Leng
- Graduate School of HeBei North University, Zhangjiakou 075000, Hebei Province, China; Hebei Key Laboratory of Metabolic Diseases, Hebei General Hospital, Shijiazhuang 050051, Hebei Province, China
| | - Yuling Xing
- Graduate School of Hebei Medical University, Shijiazhuang 050017, Hebei Province, China; Hebei Key Laboratory of Metabolic Diseases, Hebei General Hospital, Shijiazhuang 050051, Hebei Province, China
| | - Yi Liang
- Graduate School of Hebei Medical University, Shijiazhuang 050017, Hebei Province, China; Hebei Key Laboratory of Metabolic Diseases, Hebei General Hospital, Shijiazhuang 050051, Hebei Province, China
| | - Chang Wang
- Graduate School of HeBei North University, Zhangjiakou 075000, Hebei Province, China; Hebei Key Laboratory of Metabolic Diseases, Hebei General Hospital, Shijiazhuang 050051, Hebei Province, China
| | - Huijuan Ma
- Hebei Key Laboratory of Metabolic Diseases, Hebei General Hospital, Shijiazhuang 050051, Hebei Province, China.
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Wolf JM, Cameron KL, Clifton KB, Owens BD. Serum relaxin levels in young athletic men are comparable with those in women. Orthopedics 2013; 36:128-31. [PMID: 23379736 DOI: 10.3928/01477447-20130122-06] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
Relaxin was originally described as a reproductive hormone that mediated joint laxity in pregnant women and has been minimally studied in men. The purpose of this descriptive laboratory and clinical study was to evaluate serum relaxin in a young, primarily male population and compare levels between the sexes. In addition, the authors evaluated the relationship between relaxin and generalized laxity.
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Affiliation(s)
- Jennifer Moriatis Wolf
- Department of Orthopaedic Surgery, University of Connecticut Health Center, Farmington, Connecticut , USA.
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Bayram F, Gedik VT, Demir Ö, Kaya A, Gündoğan K, Emral R, Öztürk A, Uysal AR, Çorapçıoğlu D. Epidemiologic survey: reference ranges of serum insulin-like growth factor 1 levels in Caucasian adult population with immunoradiometric assay. Endocrine 2011; 40:304-9. [PMID: 21538205 DOI: 10.1007/s12020-011-9476-z] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/11/2010] [Accepted: 04/18/2011] [Indexed: 10/18/2022]
Abstract
Gender, age adjusted, population based reference ranges are necessary to use insulin-like growth factor 1 (IGF-1) as a diagnostic marker or for therapeutic monitoring in growth hormone (GH) related diseases. The aim of the present study was to describe the serum IGF-1 distribution and to calculate age and gender specific reference values for Caucasian adult population. A representative sample of 1002 male and 1039 female, totally 2041 participants aged above 18 years old was examined. The subjects suffering from diabetes mellitus, renal diseases, liver diseases, cancer, or diseases of pituitary gland were excluded by medical history, physical examination, and laboratory tests. The subjects were not using any drug that could affect IGF-1 levels. Body mass index (BMI)>30 or<18 kg/m2 were excluded. Serum IGF-1 concentrations were determined by immunoradiometric assay (IRMA). Serum IGF-1 concentrations were declined with age in both males and females after the age of 18. Males had significantly higher serum IGF-1 levels than females in the age groups 18-24, 50-69 (P<0.05), but not in others (P>0.05). The present study established age and gender specific reference ranges for serum IGF-1 levels calculated for Caucasian adult population with IRMA that could be used in medical practice.
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Affiliation(s)
- Fahri Bayram
- Department of Endocrinology and Metabolic Diseases, School of Medicine, Erciyes University, Kayseri, Turkey
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Miyamoto N, Imamura H. Lumbar Bone Mineral Density and Insulin-like Growth Factor Binding Protein-3 in Japanese Collegiate Women. ACTA ACUST UNITED AC 2010. [DOI: 10.1248/jhs.56.397] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Affiliation(s)
| | - Hiroyuki Imamura
- Faculty of Health Management, Department of Health and Nutrition, Nagasaki International University
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Karl JP, Alemany JA, Koenig C, Kraemer WJ, Frystyk J, Flyvbjerg A, Young AJ, Nindl BC. Diet, body composition, and physical fitness influences on IGF-I bioactivity in women. Growth Horm IGF Res 2009; 19:491-496. [PMID: 19467892 DOI: 10.1016/j.ghir.2009.04.001] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/05/2009] [Revised: 04/16/2009] [Accepted: 04/22/2009] [Indexed: 12/11/2022]
Abstract
OBJECTIVE Insulin-like growth factor I (IGF-I) is a metabolic-regulatory hormone that mediates a variety of physiologic functions. Body composition, fitness status and intake of certain micro- and macronutrients are associated with circulating concentrations of immunoreactive IGF-I. The influence of these factors on IGF-I bioactivity; however, is undetermined. We assessed the relationships between IGF-I bioactivity and lifestyle factors purportedly associated with IGF-I immunoreactivity. DESIGN In a cross sectional study, fasted blood samples were obtained from 44 lightly active, college-age (20+/-2 yrs) women. IGF-I bioactivity was estimated by an assay which determines the ability of serum IGFs to phosphorylate IGF-I receptors in cultured cells; free and total IGF-I were measured by immunoassay. Estradiol and progesterone were measured by immunoassay. Body mass index was calculated from measured height and weight, bone mineral density and body fat percentage measured by dual energy X-ray absorptiometry, and peak oxygen consumption (VO(2peak)) determined during a graded treadmill protocol. A food frequency questionnaire measured habitual and a 5-day food record assessed short-term micro- and macronutrient intakes. Associations between bioactive, free and total IGF-I with body composition, sex hormones, VO(2peak), and dietary intake were assessed using univariate and multiple linear regression analyses. RESULTS Associations between bioactive IGF-I with age (r=-0.36, P<0.05), body fat percentage (r=-0.32, P<0.05), estradiol (r=0.31, P<0.05) and progesterone (r=0.33, P<0.05) concentrations, habitual alcohol (r=-0.38, P<0.05) and selenium intakes (r=0.41, P<0.01), free IGF-I with age (r=-0.34, P<0.05), estradiol (r=0.48, P<0.01) and progesterone (r=0.52, P<0.001) concentrations, habitual alcohol (r=-0.33, P<0.05) and isoflavone intakes (r=0.30, P<0.05) and total IGF-I with age (r=-0.27, P<0.05) and habitual alcohol intake (r=-0.33, P<0.05) were observed. Habitual alcohol intake was a negative predictor of bioactive, free and total IGF-I in multivariate models. CONCLUSION Of the lifestyle factors measured, the most robust relationship observed was a negative association between habitual alcohol intake and all measures of IGF-I. This finding suggests that alcohol intake may blunt the physiologic actions of the IGF-I axis.
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Affiliation(s)
- J Philip Karl
- US Army Research Institute of Environmental Medicine, 42 Kansas St., Natick, MA 01760, USA
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Widdowson WM, Healy ML, Sönksen PH, Gibney J. The physiology of growth hormone and sport. Growth Horm IGF Res 2009; 19:308-319. [PMID: 19505835 DOI: 10.1016/j.ghir.2009.04.023] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 04/03/2009] [Indexed: 11/20/2022]
Abstract
The growth hormone (GH)/ insulin-like growth factor-I (IGF-I) axis exerts short-and long-term metabolic effects that are potentially important during exercise. Exercise is a potent stimulus to GH release and there is some evidence that the acute increase in GH is important in regulating substrate metabolism post-exercise. Regular exercise also increases 24-hour GH secretion rates, which potentially contributes to the physiologic changes induced by training. The effects of GH replacement in GH-deficient adults provide a useful model with which to study the effects of the more long-term effects of the GH/ IGF-I axis. There is convincing evidence that GH replacement increases exercise capacity. Measures of exercise performance including maximal oxygen uptake (VO2max) and ventilatory threshold (VeT) are impaired in GH deficiency and improved by GH replacement, probably through some combination of increased oxygen delivery to exercising muscle, increased fatty acid availability with glycogen sparing, increased muscle strength, improved body composition and improved thermoregulation. Administration of supraphysiologic doses of GH to athletes increases fatty acid availability and reduces oxidative protein loss particularly during exercise, and increases lean body mass. It is not known whether these effects translate to improved athletic performance, although recombinant human GH is known to be widely abused in sport. The model of acromegaly provides evidence that long-term GH excess does not result in improved performance but it is possible that a "window" exists in which the protein anabolic effects of supraphysiologic GH might be advantageous.
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Affiliation(s)
- W Matthew Widdowson
- Department of Endocrinology and Diabetes, Adelaide and Meath Hospital, Tallaght, Dublin 24, Ireland
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Suliman IA, Elhassan AM, Adem A, El-Bakri NK, Lindgren JU. Changes in tissue levels of growth hormone, insulin-like growth factor-I, and somatostatin in the femurs of hind-limb immobilized rats. ACTA ACUST UNITED AC 2009; 72:186-91. [PMID: 11372951 DOI: 10.1080/000164701317323453] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
Abstract
Immobilization of an extremity causes skeletal muscle atrophy and a dramatic increase in bone resorption. Growth hormone (GH) is known to play an important role in bone remodeling mediated in part by local insulin-like growth factor-I (IGF-I). In this study, we investigated changes in the levels of GH and IGF-I peptide in bone extracts from the femur after hind-limb immobilization for 5 days, 2, 4, and 8 weeks. The levels of somatostatin, which interacts with GH, were also measured in the bone extracts. GH levels increased after 8 weeks of hind-limb immobilization whereas the IGF-I concentrations increased after 2 weeks, but returned to control levels at 4 weeks, and decreased after 8 weeks of immobilization. The somatostatin levels in the bone extracts increased only after 8 weeks of hind-limb immobilization. Our findings suggest that, after hind-limb immobilization, changes in the concentrations of GH, IGF-I, and somatostatin in bone may mediate bone resorption either directly or through interaction with other factors.
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Affiliation(s)
- I A Suliman
- Department of Orthopedic Surgery, Karolinska Institutet, Huddinge University Hospital, Stockholm, Sweden.
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10
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Caton SJ, Yinglong B, Burget L, Spangler LJ, Tschöp MH, Bidlingmaier M. Low-carbohydrate high-fat diets: regulation of energy balance and body weight regain in rats. Obesity (Silver Spring) 2009; 17:283-9. [PMID: 19039316 DOI: 10.1038/oby.2008.529] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
The aim of the current investigations was to examine the effects of a low-carbohydrate high-fat diet (LC-HFD) on body weight, body composition, growth hormone (GH), IGF-I, and body weight regain after stopping the dietary intervention and returning the diet back to standard laboratory chow (CH). In study one, both adolescent and mature male Wistar rats were maintained on either an isocaloric LC-HFD or CH for 16 days before having their diet switched. In study two, mature rats were maintained on either LC-HFD or CH for 16 days to determine the effects of the LC-HFD on fat pad weight. LC-HFD leads to body weight loss in mature rats (P < 0.01) and lack of body weight gain in adolescent rats (P < 0.01). Despite less body weight, increased body fat was observed in rats maintained on LC-HFD (P < 0.05). Leptin concentrations were higher (P < 0.05), and IGF-I (P < 0.01) concentrations were reduced in the LC-HFD rats. When the diet was returned to CH following LC-HFD, body weight regain was above and beyond that which was lost (P < 0.01). The LC-HFD resulted in increased body fat and had a negative effect upon both GH and IGF-I concentrations, which might have implications for the accretion and maintenance of lean body mass (LBM), normal growth rate and overall metabolic health. Moreover, when the LC-HFD ceases and a high-carbohydrate diet follows, more body weight is regained as compared to when the LC-HFD is consumed, in the absence of increased energy intake.
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Affiliation(s)
- Samantha J Caton
- Neuroendocrine Unit, Medizinische Klinik Innenstadt, Ludwig Maximilians University, Munich, Germany
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11
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Ehrnborg C, Rosén T. Physiological and pharmacological basis for the ergogenic effects of growth hormone in elite sports. Asian J Androl 2008; 10:373-83. [DOI: 10.1111/j.1745-7262.2008.00403.x] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
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12
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Abstract
The syndrome of adult GH deficiency and the effects of GH replacement therapy provide a useful model with which to study the effects of the GH/IGF-I axis on exercise physiology. Measures of exercise performance including maximal oxygen uptake and ventilatory threshold are impaired in adult GH deficiency and improved by GH replacement, probably through some combination of increased oxygen delivery to exercising muscle, increased fatty acid availability with glycogen sparing, increased muscle strength, improved body composition, and improved thermoregulation. In normal subjects, in addition to the long-term effects of GH/IGF-I status, there is evidence that the acute GH response to exercise is important in regulating substrate metabolism after exercise. Administration of supraphysiological doses of GH to athletes increases fatty acid availability and reduces oxidative protein loss, particularly during exercise, and increases lean body mass. Despite a lack of evidence that these metabolic effects translate to improved performance, GH abuse by athletes is widespread. Tests to detect GH abuse have been developed based on measurement in serum of 1) indirect markers of GH action, and 2) the relative proportions of the two major naturally occurring isoforms (20 and 22kDa) of GH. There is evidence that exercise performance and strength are improved by administration of GH and testosterone in combination to elderly subjects. The potential benefits of GH in these situations must be weighed against potential adverse effects.
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Affiliation(s)
- James Gibney
- Department of Endocrinology and Diabetes, Adelaide and Mental Hospital, Tallaght, Dublin 24, Ireland
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Morimoto LM, Newcomb PA, White E, Bigler J, Potter JD. Variation in plasma insulin-like growth factor-1 and insulin-like growth factor binding protein-3: personal and lifestyle factors (United States). Cancer Causes Control 2006; 16:917-27. [PMID: 16132801 DOI: 10.1007/s10552-005-2702-3] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2004] [Accepted: 02/22/2005] [Indexed: 02/07/2023]
Abstract
Insulin-like growth factors (IGFs) play an important role in cell proliferation and apoptosis, and recent epidemiologic studies have suggested that circulating IGF-1 and IGF binding protein-3 (IGFBP-3) may be related to colorectal, breast, and prostate cancer risk. The purpose of this analysis was to investigate the role of various personal and lifestyle factors in the inter-individual variation of circulating IGF-1 and IGFPB-3. We measured plasma levels of IGF-1 and IGFBP-3 in a sequential sample of 333 population-based control subjects enrolled in the Seattle Colorectal Cancer Family Registry from August 1999 through December 2001, who had provided a blood sample. Total IGF-1 and IGFBP-3 were measured from plasma samples using ELISA assays. Interviewer-administered questionnaires collected data on various personal and lifestyle factors. Multivariate-adjusted linear regression was used to assess the associations between specific personal and lifestyle factors with IGF-1 and IGFBP-3 levels. Age, body mass index, and postmenopausal hormone use were statistically significantly inversely related to IGF-1 concentrations, and milk consumption was significantly positively related to IGF-1 levels. Only age was significantly related to circulating IGFBP-3. Although the sources of inter-individual variation of IGF-1 and IGFB-3 are not yet fully understood, this analysis provides some insights into factors that may contribute.
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Affiliation(s)
- Libby M Morimoto
- Public Health Sciences, Fred Hutchinson Cancer Research Center, Seattle, WA 98109, USA
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14
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Elloumi M, El Elj N, Zaouali M, Maso F, Filaire E, Tabka Z, Lac G. IGFBP-3, a sensitive marker of physical training and overtraining. Br J Sports Med 2005; 39:604-10. [PMID: 16118296 PMCID: PMC1725308 DOI: 10.1136/bjsm.2004.014183] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
OBJECTIVE To investigate the response of the somatotrope axis (insulin-like growth factor-1 (IGF-1), insulin-like growth factor binding protein-3 (IGFBP-3)) to intense exercise in relation to tiredness. METHODS The study involved 11 rugby players who completed a questionnaire intended to evaluate fitness or, conversely, overtraining and who agreed to plasma samples being taken before and after an international rugby match. RESULTS The main finding of our study is that we observed strong negative correlations between IGF-1 (r = 0.652) and IGFBP-3 (r = 0.824) levels and the overtraining state estimated using the French Society of Sport Medicine questionnaire. In particular, there was a fall (of up to 25%) in IGFBP-3 levels after the match in the more fatigued subjects compared to an increase (of up to 40%) in fit subjects. CONCLUSIONS A fall in IGFBP-3 in response to an intense bout of exercise may represent an index of tiredness in highly trained sportsmen, as indicated by the scores obtained from the overtraining questionnaire.
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Affiliation(s)
- M Elloumi
- Laboratoire de Physiologie de la Performance Motrice, Université Blaise Pascal, Bat Biologie B, Les Cézeaux, 63177 Aubière Cedex, France
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15
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Morimoto LM, Newcomb PA, White E, Bigler J, Potter JD. Variation in plasma insulin-like growth factor-1 and insulin-like growth factor binding protein-3: genetic factors. Cancer Epidemiol Biomarkers Prev 2005; 14:1394-401. [PMID: 15941947 DOI: 10.1158/1055-9965.epi-04-0694] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
Insulin-like growth factors (IGFs) play key roles in cell proliferation and apoptosis. Whereas relatively stable within individuals, IGFs vary substantially between individuals, and a large component of this variation may be determined by genetic factors. Several polymorphisms in IGF genes have been identified, although their functional significance is not clear. We evaluated the association of polymorphisms in IGF-1 and IGFBP-3 and circulating levels of IGF-1 and IGFBP-3 in 323 population-based control subjects enrolled in a case-control study of colorectal cancer from September 1999 through February 2002. Total IGF-1 and IGFBP-3 levels were measured using ELISA assays, and all subjects were genotyped for a microsatellite polymorphism in IGF-1 and a single nucleotide polymorphism in IGFBP-3. Multiple linear regression was used to assess the association of genotype with circulating IGFs. IGF-1 levels were unrelated to either polymorphism. IGFBP-3 was significantly associated with IGFBP-3 genotype, with IGFBP-3 levels increasing from CC (1,895 ng/mL) --> GC (2,029 ng/mL) --> GG (2,182 ng/mL), (p-trend < 0.001). Having an IGF-1 genotype other than homozygous for the 19-repeat allele was associated with higher IGFBP-3 levels (1,945 versus 2,052 ng/mL). Furthermore, both IGF-1 and IGFBP-3 genotypes modified the relationship between postmenopausal hormone use and IGFs. This analysis provides evidence that common variation in IGF genes may contribute to the variation in circulating levels observed between individuals.
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Affiliation(s)
- Libby M Morimoto
- Public Health Sciences, Fred Hutchinson Cancer Research Center, Seattle, Washington, USA
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16
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Berg U, Bang P. Exercise and circulating insulin-like growth factor I. HORMONE RESEARCH 2005; 62 Suppl 1:50-8. [PMID: 15761233 DOI: 10.1159/000080759] [Citation(s) in RCA: 69] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Determinations of serum concentrations of total insulin-like growth factor I (tIGF-I) are important in the diagnosis, monitoring of treatment and safety evaluation of patients with growth disorders and/or metabolic disease. It is well established that tIGF-I status varies over time. Changes in tIGF-I levels in relation to an acute bout of exercise or repeated bouts, known as training, are likely to contribute to this variation. Serum tIGF-I has also been found to be of predictive value in growth prediction models employed before the start of growth hormone (GH) treatment. Furthermore, IGF-I generation tests have been suggested to be of value in the assessment of the growth response to GH administration in patients suspected of GH deficiency with or without some degree of GH insensitivity. This is discussed elsewhere in this issue. Recent progress in our understanding of growth hormone-dependent and -independent expression of the IGF1 gene in skeletal muscle and the role of sufficient energy intake during training for muscle and liver generation of IGF-I raises important questions regarding their relative contribution to the circulating pool of IGF-I. The present review is focused on circulating levels of tIGF-I in relation to a single bout of exercise or to a period of training. In addition, the expression of IGF-I locally in muscle in response to these stimuli will be discussed.
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Affiliation(s)
- Ulrika Berg
- Paediatric Endocrinology Unit, Department of Woman and Child Health, Karolinska University Hospital, Stockholm, Sweden
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17
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Berggren A, Ehrnborg C, Rosén T, Ellegård L, Bengtsson BA, Caidahl K. Short-term administration of supraphysiological recombinant human growth hormone (GH) does not increase maximum endurance exercise capacity in healthy, active young men and women with normal GH-insulin-like growth factor I axes. J Clin Endocrinol Metab 2005; 90:3268-73. [PMID: 15784718 DOI: 10.1210/jc.2004-1209] [Citation(s) in RCA: 57] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
CONTEXT Despite the fact that the use of GH as a doping agent in sports is widespread, little is known about its short-term effects. OBJECTIVE The objective was to study the effects of GH on exercise capacity. DESIGN A double-blind, placebo-controlled study was used, with a treatment period of 28 d. SETTING Subjects from general community studied ambulatory at a university hospital. PARTICIPANTS Thirty healthy active young normal volunteers (15 women and 15 men) were recruited by local announcement, and all completed the study. INTERVENTION All subjects were randomized to receive a low GH dose (0.033 mg/kg.d or 0.1 IU/kg.d), a high GH dose (0.067 mg/kg.d or 0.2 IU/kg.d), or placebo. MAIN OUTCOME MEASURES Power output and oxygen uptake on bicycle exercise were the main outcome measures. RESULTS We found no effect of the low or high dosages of GH on maximum oxygen uptake during exercise (mean +/- se for placebo, 45.2 +/- 1.6 to 45.2 +/- 2.1 ml/kg.min; GH low dose, 42.8 +/- 1.6 to 42.8 +/- 1.6 ml/kg.min; GH high dose, 44.8 +/- 3.4 to 44.8 +/- 2.2 ml/kg.min; not significant by two-way ANOVA). Neither was there any effect on maximum achieved power output during exercise or on blood pressure, heart rate, or the electrocardiographic ST level at rest or during exercise. GH significantly increased total body weight (P = 0.028), an effect predominantly ascribed to fluid retention (increased extracellular water volume), whereas muscle mass (as indicated by intracellular water volume) did not change. However, changes in the latter correlated to changes in physical performance, possibly due to different training efforts. CONCLUSION Administration of supraphysiological recombinant human GH during a period of 4 wk does not improve power output or oxygen uptake.
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Affiliation(s)
- Annika Berggren
- Department of Clinical Physiology, Sahlgrenska University Hospital, SE-41345 Göteborg, Sweden
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Sato Y, Yoshitomi A, Abe T. Acute growth hormone response to low-intensity KAATSU resistance exercise: Comparison between arm and leg. ACTA ACUST UNITED AC 2005. [DOI: 10.3806/ijktr.1.45] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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Ay A, Yurtkuran M. Influence of Aquatic and Weight-Bearing Exercises on Quantitative Ultrasound Variables in Postmenopausal Women. Am J Phys Med Rehabil 2005; 84:52-61. [PMID: 15632489 DOI: 10.1097/01.phm.0000146500.85850.be] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
OBJECTIVE In this prospective, controlled study, the effects of weight bearing and aquatic exercises on the calcaneal ultrasonic scores of postmenopausal sedentary women was investigated. DESIGN A total of 62 postmenopausal sedentary women (mean age, 54.1 +/- 7 yrs) with broadband ultrasound attenuation (BUA) T-score variables less than -1 were admitted to Ataturk Balneotherapy and Rehabilitation Center and randomized into aquatic exercise (n = 21), weight-bearing exercise (n = 21), and control (n = 20) groups. The subjects were told to perform the aerobic exercises according to the Borg scale. Quantitative ultrasound variables, BUA, and speed of ultrasound were evaluated after the 6-mo training study. RESULTS Calcaneal BUA increased in aquatic exercise and weight-bearing exercise groups by 3.1% and 4.2% (P < 0.05, P < 0.05) respectively. There was a decrease in BUA by 1.3% in the control group (P > 0.05). Speed of ultrasound did not change in the aquatic exercise, weight-bearing exercise, or the control groups. There were no statistically significant differences between the exercise groups for BUA and speed of ultrasound. The percentage changes in the aquatic exercise and weight-bearing exercise groups were statistically significant when compared with the control group for BUA (P < 0.01, P < 0.01) and speed of ultrasound (P < 0.05, P < 0.05). CONCLUSIONS Although weight-bearing physical activity is known to be superior to non-weight-bearing activity to increase the bone mass, our present evidence shows that aquatic and weight-bearing exercises both can increase calcaneal BUA.
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Affiliation(s)
- Alev Ay
- Department of Physical Therapy and Rehabilitation, Atatürk Balneotherapy and Rehabilitation Center, Uludağ University, Kükürtlü Kaplicalari, PK:16080 Bursa, Turkey
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20
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Adiyaman P, Ocal G, Berberoğlu M, Evliyaoğlu O, Aycan Z, Cetinkaya E, Bulca Y, Ersöz G, Akar N. Alterations in serum growth hormone (GH)/GH dependent ternary complex components (IGF-I, IGFBP-3, ALS, IGF-I/IGFBP-3 molar ratio) and the influence of these alterations on growth pattern in female rhythmic gymnasts. J Pediatr Endocrinol Metab 2004; 17:895-903. [PMID: 15270408 DOI: 10.1515/jpem.2004.17.6.895] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
BACKGROUND AND AIM Normal growth in children is regulated to a great extent through the actions of the GH/IGF-I axis, a system consisting of GH and its mediators (ternary complex) that modulate growth in many tissues. The ternary complex (IGF-I/IGFBP-3/ALS) provides an acute regulatory mechanism in which IGF-I may be mobilized from the circulating reservoir of 150 kDa complexes to the tissues. Acute exercise is known to be a stimulus for GH secretion. The beneficial effects of scheduled exercise on body composition are also well established. However, the impact of strenuous exercise on the pubertal development of child athletes is still not well understood. The first goal of this study was to assess the acute effects of high intensity exercise training on GH-dependent ternary complex components in female rhythmic gymnasts compared to age-matched healthy female controls with normal physical activity. The second goal was to explore the influence of these exercise-induced changes on skeletal and pubertal growth in the same group prospectively over a period of 4 years. SUBJECTS AND METHODS Seventeen female rhythmic gymnasts, aged 11.4 +/- 0.9 years, who had 10 h per week intense exercise for at least 4 months volunteered to participate in this study. Anthropometric measurement of height (Height SDS for chronological age [HtSDS(CA)], parentally adjusted height, predicted adult height), bone age and weight (BMI) were made using standard techniques in gymnasts and controls (aged 12.5 +/- 3.0 years, n = 12). Gymnasts were followed up to 4 years to observe growth velocity and pubertal progression. In order to determine the acute impact of exercise on levels of GH and GH-dependent ternary complex component (IGF-I, IGFBP-3, ALS, IGF-I/IGFBP-3 molar ratio), blood samples were obtained from gymnasts after a routine 2-h high-intensity training program and then after a 2-day rest period. These results were compared with age-matched controls with no scheduled sports activity. RESULTS Despite the significant increment in serum GH and GH-dependent components immediately following the exercise, serum GH/IGF-I levels showed a significant decrement (p < 0.01) after a 2-day rest in gymnasts, to a nadir as low as those of the control subjects' baseline levels (p < 0.01). There was no difference in anthropometric characteristics of gymnasts and controls except BMI; gymnasts were leaner than controls. During a 4-year follow up, there were no differences between the gymnasts and controls in regard to skeletal growth and reaching their predicted height. However, in gymnasts there was a delay in pubertal tempo but not in growth. CONCLUSION Intense exercise induces an acute rise in GH levels, but this acute elevation rapidly normalizes after a 2-day rest in female rhythmic gymnasts. These fluctuations in serum GH and GH-dependent ternary complex components had no reflection on the skeletal growth patterns in gymnasts over the 4-year follow up but there was a delay in their pubertal progression.
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Affiliation(s)
- P Adiyaman
- Department of Pediatric Endocrinology, Ankara University, Faculty of Medicine, Ankara, Turkey.
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Affiliation(s)
- Alon Eliakim
- Child Health & Sports Center, Pediatric Department, Meir General Hospital, Sackler School of Medicine, Tel-Aviv University, Israel.
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Mejri S, Bchir F, Koubâa D, Ben Slama C. Réponses de GH, IGF-1 et IGF-BP3 à un exercice submaximal : différences entre sujets entraînés et sédentaires. Sci Sports 2004. [DOI: 10.1016/s0765-1597(03)00168-0] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Ay A, Yurtkuran M. Evaluation of hormonal response and ultrasonic changes in the heel bone by aquatic exercise in sedentary postmenopausal women. Am J Phys Med Rehabil 2003; 82:942-9. [PMID: 14627931 DOI: 10.1097/01.phm.0000098039.58584.59] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
OBJECTIVE This study is based on whether moderate increased physical activity as aquatic exercise has anabolic effects on bone and evaluates this in terms of quantitative ultrasound and hormonal variables. DESIGN In this study, 41 postmenopausal sedentary women were admitted to Atatürk Balneotherapy and Rehabilitation Center, according to T scores of broadband ultrasound attenuation. Subjects were followed for 6 mos in aquatic exercise and control groups. The subjects were told to perform the aerobic exercises according to the Borg Scale. Ultrasonic and hormonal evaluation was done before and after the 6-mo training study. RESULTS In the exercise group, there were 36%, 75%, and 54% increases in the serum levels of insulin-like growth factor-1, growth hormone, and calcitonin, respectively. In addition, a 31% decrease was found in the serum levels of parathormone compared with the initial values. In the control group, serum levels of growth hormone decreased by 61%, but there were no statistically significant changes in the serum levels of insulin-like growth factor-1, calcitonin, or parathormone. T scores of broadband ultrasound attenuation and speed of sound increased by 19% and 63% in the exercise group, respectively, whereas there were decreases in the control group for the same variables. There were statistically significant differences between the control and the aquatic exercise groups for the 6-mo percentage of changes in broadband ultrasound attenuation and speed-of-sound T scores, insulin-like growth factor-1, growth hormone, parathormone, and calcitonin. CONCLUSIONS Aquatic exercise was determined to be effective to make an anabolic effect on the bone of the postmenopausal, sedentary subjects.
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Affiliation(s)
- Alev Ay
- Department of Physical Therapy and Rehabilitation, Uludağ University Atatüurk Balneotherapy and Rehabilitation Center, Kükürtlü, Bursa, Turkey
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Affiliation(s)
- Anders Juul
- Department of Growth and Reproduction, University of Copenhagen, Blegdamsvej 9 Rigshopitalet, Section 5064, Copenhagen 2100, Denmark.
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25
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Manetta J, Brun JF, Fedou C, Maïmoun L, Prefaut C, Mercier J. Serum levels of insulin-like growth factor-I (IGF-I), and IGF-binding proteins-1 and -3 in middle-aged and young athletes versus sedentary men: relationship with glucose disposal. Metabolism 2003; 52:821-6. [PMID: 12870155 DOI: 10.1016/s0026-0495(03)00096-9] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
The goal of this study was to characterize the respective effects of aging and endurance training on serum insulin-like growth factor I (IGF-I), as well as IGF-binding proteins (IGFBP)-1 and -3 in relationship with glucose disposal. Thirty-two subjects (16 middle-aged men: 8 cyclists and 8 sedentary men; and 16 young men: 8 cyclists and 8 sedentary men) were compared in this study. Insulin sensitivity (SI) and glucose effectiveness (Sg) were assessed by the minimal model. Endurance training increased SI, Sg, and IGFBP-1 and -3 in both age groups (P<.05), but the older group showed a greater increase in SI and IGFBP-1 than the younger group (P<.05). IGF-I was increased only in the middle-aged trained men (P<.05). An effect of aging was found in the sedentary subjects, who presented lower IGF-I and SI (P<.05) when older. This effect disappeared with training since IGF-I and SI were nearly identical in young and middle-aged trained subjects. SI was correlated with IGFBP-1 (P<.01). These data suggest that (1) endurance training increases SI, Sg, and IGFBP-1 and -3 in men and, for SI and IGFBP-1, this increase becomes more pronounced with age; (2) endurance training may attenuate the aged-related decline in SI and IGF-I; and (3) IGFBP-1 may protect against the risk of hypoglycemia by counteracting the hypoglycemic effect of IGF-I in such situations of high SI.
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Affiliation(s)
- J Manetta
- Metabolic Unit, Service Central de Physiologie Clinique, Centre d'Exploration et de Réadaptation des Anomalies Métaboliques et Musculaires, Hôpital Lapeyronie, Monpellier, France
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Manetta J, Brun JF, Maimoun L, Callis A, Préfaut C, Mercier J. Effect of training on the GH/IGF-I axis during exercise in middle-aged men: relationship to glucose homeostasis. Am J Physiol Endocrinol Metab 2002; 283:E929-36. [PMID: 12376319 DOI: 10.1152/ajpendo.00539.2001] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The aim of this study was to compare circulating levels of growth hormone (GH), IGF-I, and IGF-binding protein (IGFBP)-1 and IGFBP-3 in response to a long-duration endurance exercise in trained vs. sedentary middle-aged males and to determine whether a relationship with glucose homeostasis exists. Seven trained men (Tr) were compared with seven age-matched sedentary men (Sed) during two trials of 60 min of cycling exercise performed below (-VT) and above (+VT) the ventilatory threshold. Insulin sensitivity (S(I)) was higher in Tr than in Sed (P < 0.001). Basal GH, IGF-I, and IGFBP-1 and -3 were higher in Tr (P < 0.05). During +VT, Tr had a threefold higher GH response, whereas their blood glucose level was better maintained (P < 0.05). Basal IGFBP-1 was correlated with S(I) (P < 0.01). These data indicate that endurance training in middle-aged men increased the activity of the GH/IGF-I system and improved glucoregulation both at rest and during high-intensity endurance exercise.
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Affiliation(s)
- Jérôme Manetta
- Service Central de Physiologie Clinique: Centre d'Exploration et de Réadaptation des Anomalies Métaboliques et Musculaires, hôpital Lapeyronie, 34295 Montpellier, France.
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27
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Scheett TP, Nemet D, Stoppani J, Maresh CM, Newcomb R, Cooper DM. The effect of endurance-type exercise training on growth mediators and inflammatory cytokines in pre-pubertal and early pubertal males. Pediatr Res 2002; 52:491-7. [PMID: 12357041 DOI: 10.1203/00006450-200210000-00006] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Recent studies demonstrate an unexpected reduction in circulating levels of IGF-I after 5 wk of endurance-type exercise training in adolescent boys and girls and prepubertal girls. We hypothesized that the reduction in IGF-I would be accompanied by a training-associated stimulation of proinflammatory cytokines IL-1beta, IL-6, or tumor necrosis factor-alpha (TNF-alpha), each of which can inhibit the GH-->IGF-I axis. Healthy boys (age range 9-11 y old, mean Tanner 1.7) volunteered for the study and were randomized to control (n = 14) and training groups (n = 12) for 5 wk. After the intervention, significant increase in fitness was observed in the training group but not control group. Although IGF-I was correlated at baseline to peak oxygen consumption in all subjects, there was a significant decrease in IGF-I and IGF binding protein-3 in the training subjects (-12.8 +/- 7.3% and -17.5 +/- 7%, respectively, p < 0.05). In contrast, IGF binding protein-2, known to inhibit anabolic effects of IGF-I, increased in the training subjects (27.8 +/- 11%, p < 0.02) as did IL-1beta and TNF-alpha (51.5 +/- 30.22%, p < 0.02, and 44.5 +/- 23.2%, p < 0.02, respectively). Finally, we also found that GHBP was inversely correlated with fitness, suggesting altered GH function in more-sedentary boys. Thus, these data support the hypothesis that a sustained increase in physical activity can stimulate proinflammatory cytokines, which may contribute to suppression of the GH-->IGF-I axis. Physical activity can influence growth and development through its influence on anabolic and catabolic mediators.
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Affiliation(s)
- Timothy P Scheett
- Center for the Study of Health Effects of Exercise in Children, University of California, Irvine, College of Medicine, Orange, California, USA
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Buckley JD, Abbott MJ, Brinkworth GD, Whyte PBD. Bovine colostrum supplementation during endurance running training improves recovery, but not performance. J Sci Med Sport 2002; 5:65-79. [PMID: 12188088 DOI: 10.1016/s1440-2440(02)80028-7] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
This study examined the effect of supplementation with concentrated bovine colostrum protein powder (intact) on plasma insulin-like growth factor I (IGF-I) concentrations, endurance running performance and recovery. Thirty physically active males completed 8 weeks of running training whilst consuming 60 g x day(-1) of intact powder (n=17) or a concentrated whey protein powder placebo (n=13) in a randomised, double-blind, parallel design. Plasma IGF-I concentrations were measured prior to subjects performing two (approximately 30 min) incremental treadmill running tests to exhaustion (RUN1 and RUN2) separated by 20 min of passive recovery at Weeks 0. 4 and 8. Plasma IGF-I concentrations showed little change in either group (p=0.83). Effective peak running speed (PRSE; i.e. equivalent of peak power) during RUN1 was not different between groups at Week 0 (p>0.99), and had increased by a similar amount in both groups by Week 4 (mean+/-SD, intact 2.2+/-4.0%, placebo 3.2+/-3.3%; 95% confidence interval [95% CI 15.7 to -13.7%; p=0.89) and Week 8 (intact 3.6+/-5.6%, placebo 3.4+/-4.4 %; 95% CI -100.0 to 100.0%; p>0.99). PRSE was less in both groups during RUN2 (p<0.05), but was not significantly different between groups at Week 0 (p>0.99). PRSE during RUN2 tended to have increased more in the placebo group by Week 4 (intact 1.8+/-4.8%, placebo 4.2+/-3.9%; 95% CI 0.2 to -5 0%; p=0.07), but the intact group had increased PRSE significantly more by Week 8 (intact 4.6+/-6.1%, placebo 2.0+/-4.5%; 95% Cl 0.0 to 5.2%; p=0.05). resulting in a significantly faster PRSE (p=0.003). We conclude that supplementation with intact powder did not increase plasma IGF-I concentrations or improve performance during an initial bout of incremental running to exhaustion in our sample. However, performance during a second bout of exercise may be improved by as much as 5.2% in the average subject after 8 weeks of supplementation, possibly due to an enhancement of recovery.
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Affiliation(s)
- J D Buckley
- Centre for Research in Education and Sports Science, School of Physical Education Exercise and Sport Studies, University of South Australia, Adelaide
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Abstract
The recent "obesity epidemic" among children and adolescents is a major public health concern. The mechanisms responsible for the increased incidence of childhood obesity are not yet well understood. The absence of a clear mechanism makes treating the obese child or adolescent a difficult task, and standardized therapeutic approaches simply do not yet exist. Metabolic derangements associated with obesity may contribute to the difficulty in treatment. Observed abnormalities in the growth hormone (GH)-insulin-like growth factor-I (IGF-I) axis in obese adults and the impact of exercise on the GH-IGF-I system are of particular relevance to the growing obese child. In this review, we focus on the interacting mechanisms of diet and exercise through specific hormonal mediators and their contribution to the current obesity epidemic. An improved understanding of these mechanisms may be helpful in creating effective treatment programs for children with obesity.
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Affiliation(s)
- Dan Nemet
- Center for the Study of Health Effects of Exercise in Children, University of California, Irvine, College of Medicine, Orange 92868, USA.
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30
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Consitt LA, Copeland JL, Tremblay MS. Endogenous anabolic hormone responses to endurance versus resistance exercise and training in women. Sports Med 2002; 32:1-22. [PMID: 11772159 DOI: 10.2165/00007256-200232010-00001] [Citation(s) in RCA: 68] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
Research in exercise endocrinology has flourished over the past few decades. In general, research examining short- and long-term hormone responses to endurance exercise preceded studies on resistance exercise, and research on women lagged behind research on men. Sufficient data are now available to allow a comparison of endogenous anabolic hormone responses to endurance versus resistance exercise and training in women. Circulating levels of testosterone, dehydroepiandrosterone, dehydroepiandrosterone sulphate, estradiol, growth hormone and cortisol have been shown to increase in response to an acute bout of endurance exercise in women. However, only growth hormone, estradiol and cortisol have been reported to increase following resistance exercise. Hormone changes following training, either endurance or resistance, have been variable, probably because of differences in experimental design and major differences in the length, intensity and volume of training programmes. With the notable exception of growth hormone, the anabolic hormones reviewed here appear to decline with endurance training. Resistance training has little effect on resting hormone levels, except insulin-like growth factor-I, which has been shown to increase following a training programme. These hormone changes potentially have both metabolic and hypertrophic implications, and future research needs to focus on the biological significance of these adaptations.
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Affiliation(s)
- Leslie A Consitt
- Faculty of Kinesiology, University of New Brunswick, Fredericton, New Brunswick, Canada
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Abstract
This review summarizes the interactions between growth hormone (GH) and exercise. Exercise has profound effects upon the GH-insulin-like growth factor I axis per se. In addition, there is increasing evidence that such physiological perturbations might be influential in the performance responses to repeated training. However, the ergogenic effects of systemic administration of recombinant human GH by athletes and bodybuilders remain unproven. What is certain is that the prevalence of GH abuse by sportspeople will increase, not least because it is currently undetectable. The frequent and potentially severe side-effects associated with such 'doping' will be of increasing relevance to endocrinologists.
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Affiliation(s)
- P J Jenkins
- Department of Endocrinology, St Bartholomew's Hospital, London, UK.
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Eliakim A, Scheett TP, Newcomb R, Mohan S, Cooper DM. Fitness, training, and the growth hormone-->insulin-like growth factor I axis in prepubertal girls. J Clin Endocrinol Metab 2001; 86:2797-802. [PMID: 11397890 DOI: 10.1210/jcem.86.6.7560] [Citation(s) in RCA: 18] [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: 11/19/2022]
Abstract
We recently demonstrated that a brief endurance type training program led to increases in thigh muscle mass and peak oxygen uptake (VO(2)) in prepubertal girls. In this study, we examined the effect of training on the GH-->insulin-like growth factor I (GH-->IGF-I) axis, a system known to be involved both in the process of growth and development and in the response to exercise. Healthy girls (mean age 9.17 +/- 0.10 yr old) volunteered for the study and were randomized to control (n = 20) and training groups (n = 19) for 5 weeks. Peak VO(2), thigh muscle volume, and blood samples [for IGF-I, IGF-binding proteins (IGFBP)-1 to -6, and GHBP] were measured. At baseline, IGF-I was significantly correlated with both peak VO(2) (r = 0.44, P < 0.02) and muscle volume (r = 0.58, P < 0.004). IGFBP-1 was negatively correlated with muscle volume (r = -0.71, P < 0.0001), as was IGFBP-2. IGFBP-4 and -5 were significantly correlated with muscle volume. We found a threshold value of body mass index percentile (by age) of about 71, above which systematic changes in GHBP, IGFBP-1, and peak VO(2) per kilogram were noted, suggesting decreases in the following: 1) GH function, 2) insulin sensitivity, and 3) fitness. Following the training intervention, IGF-I increased in control (19.4 +/- 9.6%, P < 0.05) but not trained subjects, and both IGFBP-3 and GHBP decreased in the training group (-4.2 +/- 3.1% and -9.9 +/- 3.8%, respectively, P < 0.05). Fitness in prepubertal girls is associated with an activated GH-->IGF-I axis, but, paradoxically, early in a training program, children first pass through what appears to be a neuroendocrine state more consistent with catabolism.
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Affiliation(s)
- A Eliakim
- Connecticut Children's Medical Center, University of Connecticut Health Center, Farmington, Connecticut 06030, USA
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Nindl BC, Kraemer WJ, Marx JO, Arciero PJ, Dohi K, Kellogg MD, Loomis GA. Overnight responses of the circulating IGF-I system after acute, heavy-resistance exercise. J Appl Physiol (1985) 2001; 90:1319-26. [PMID: 11247930 DOI: 10.1152/jappl.2001.90.4.1319] [Citation(s) in RCA: 67] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
This study evaluated the individual components of the insulin-like growth factor I (IGF-I) system [i.e., total and free IGF-I, insulin-like growth factor binding protein (IGFBP)-2 and -3, and the acid-labile subunit (ALS)] in 10 young, healthy men (age: 22 +/- 1 yr, height: 177 +/- 2 cm, weight: 79 +/- 3 kg, body fat: 11 +/- 1%) overnight for 13 h after two conditions: a resting control (Con) and an acute, heavy-resistance exercise protocol (Ex). The Ex was a high-volume, multiset exercise protocol that alternated between 10- and 5-repetition maximum sets with 90-s rest periods between sets. The Ex was performed from 1500 to 1700; blood was obtained immediately postexercise and sampled throughout the night (every 10 min for the first hour and every hour thereafter) until 0600 the next morning. For the first hour, significant differences (P < or = 0.05) were only observed for IGFBP-3 (Ex: 3,801 > Con: 3,531 ng/ml). For the overnight responses, no differences were observed for total or free IGF-I or IGFBP-3, whereas IGFBP-2 increased (Ex: 561 > Con: 500 ng/ml) and ALS decreased (Ex: 35 < Con: 39 microg/ml) after exercise. The results from this study suggest that the impact that resistance exercise exerts on the circulating IGF-I system is not in the alteration of the amount of IGF-I but rather of the manner in which IGF-I is partitioned among its family of binding proteins. Thus acute, heavy-resistance exercise can lead to alterations in the IGF-I system that can be detected in the systemic circulation.
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Affiliation(s)
- B C Nindl
- Intercollege Graduate Program in Physiology, The Pennsylvania State University, University Park, Pennsylvania 16801, USA.
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O'Toole ML, Johnson KC, Satterfield S, Bush AJ, Koo WW, Klesges RC, Applegate WB. Do sweat calcium losses affect bone mass during firefighter training? J Occup Environ Med 2000; 42:1054-9. [PMID: 11094783 DOI: 10.1097/00043764-200011000-00003] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Although participation in vigorous exercise is associated with increased bone mass, recent evidence suggests that loss of calcium in sweat may result in a negative calcium balance and, ultimately, a decrease in bone mass. Anthropometric characteristics, habitual physical activity levels, dietary calcium intake, bone mineral content, and bone turnover markers were measured in 42 male recruits before and after 4 months of firefighter training. During two strenuous mid-training sessions, sweat calcium concentrations were measured; they averaged 1.1 mM. Whole body and total hip bone mineral content increased significantly, as did one marker of bone formation, and were not associated with sweat calcium concentration. This study demonstrates that intense physical training sessions that produce high sweat rates do not have an adverse effect on the bone mineral content of healthy young men.
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Affiliation(s)
- M L O'Toole
- Department of Preventive Medicine, University of Tennessee, Memphis, USA.
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Snow CM, Rosen CJ, Robinson TL. Serum IGF-I is higher in gymnasts than runners and predicts bone and lean mass. Med Sci Sports Exerc 2000; 32:1902-7. [PMID: 11079520 DOI: 10.1097/00005768-200011000-00013] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
INTRODUCTION We examined the relationships between insulin-like growth factor I (IGF-I), its binding protein (IGFBP-3), body composition, and bone mineral density (BMD) in collegiate runners (N = 13), gymnasts (N = 10), and noncompetitive women (N = 10). METHODS Subjects were evaluated by dual-energy x-ray absorptiometry for body composition and BMD of the spine, hip, and whole body, fasting serum levels of IGF-I and IGFBP-3, and dietary intake. The ratio IGF-I/IGFBP-3 was calculated as a marker of IGF-I bioavailability. RESULTS In ANOVA, IGF-I and IGF-I/IGFBP-3 in athletes with oligomenorrhea and amenorrhea did not differ from eumenorrheic athletes; thus, values were pooled. Lean/height2 and bone mass at the hip and spine were higher in gymnasts than runners and controls. Total caloric intake was similar between groups. IGF-I and IGF-I/IGFBP-3 differed between groups with gymnasts having higher IGF-I values than runners (397+/-58 vs 288+/-73 ng x mL(-1), P < 0.001) and higher IGF-I/IGFBP-3 than controls and runners (0.065+/-0.009 vs 0.056+/-0.008 vs 0.045+/-0.009, P = 0.0001). In simple regression, IGF-I and IGF-/IGFBP-3 were related to lean/height2 and BMD of the lumbar spine and hip (P < 0.01-0.0001). IGF-I and IGF-I/IGFBP-3 were multicollinear; thus, the ratio was used in subsequent stepwise regression. Lean mass, corrected for body surface area (height2), independently predicted spine and trochanteric BMD (R2 = 0.26, 0.28, respectively), whereas IGF-I/IGFBP-3 and lean/height2 together contributed to 48% of the variance in femoral neck BMD. CONCLUSION We conclude that, in this group of young adult women, lower BMD in runners may be due, in part, to lower levels of IGF-I and the ratio of IGF-I-to-IGFBP-3 and that IGF-I may mediate the relationship between bone and lean mass.
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Affiliation(s)
- C M Snow
- Bone Research Laboratory, Oregon State University, Corvallis 97331, USA
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Morimoto Y, Tanaka T, Kito S, Morimoto A, Haneji T, Kimura M, Ohba T. Quantitative radiographic changes in the mandible and the tibia in systemically loaded rats fed a low-calcium diet. Oral Dis 2000; 6:310-7. [PMID: 11002414 DOI: 10.1111/j.1601-0825.2000.tb00144.x] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The combined effect of the duration of loaded physical exercise and the percentage of calcium intake on the mandible and tibia were studied in developing male rats. For the loaded exercise, rats ran on a treadmill at a rate of 12 m per min for either 1 or 2 h per day. A total of 54 4-week-old male Wistar rats were randomly assigned to one of six groups. After 4 weeks of the diet and loaded exercise, the rats were killed and their mandibles and tibia were removed. Each individual bone was assessed by radiography and the radiographs were then used for measurements of cortical thickness, bone length and bone width. All radiographic images were analyzed using a computer-based scanner image analysis system. In addition, we measured the dry weight both of the tibia and mandible. The results demonstrated that significant differences in cortical thickness, bone length, bone width, and bone weight, both of the tibia and the mandible, were detectable between the normal diet group and the low-calcium diet group. Among the normal diet groups, significant differences were found in cortical thickness, bone length, bone width, and bone weight of the tibia, whereas no significant differences in either cortical bone thickness, bone length or bone weight of the mandible were detected. In contrast, among the low-calcium diet groups, no significant differences were detected in cortical thickness, bone length, bone width or bone weight for either the tibia or the mandible. Our results suggested that systemic exercise, such as running, promote the linear dimensions and the cortical thickness of the tibia in response to local stimuli. Furthermore, sufficient calcium intake appears to be necessary to allow the effect of systemic exercise on tibial bone growth to occur. In contrast, systemic loaded exercise does not promote either bone growth or development of the mandible even under conditions of sufficient calcium intake.
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Affiliation(s)
- Y Morimoto
- Department of Dental Radiology, Kyushu Dental College, Kokurakita-ku, Kitakyushu 803-8580, Japan.
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Ryu H, Lee MS, Jeong SM, Lee JH, Kang CW, Lee DY, Chung HT. Modulation of neuroendocrinological function by psychosomatic training: acute effect of ChunDoSunBup Qi-training on growth hormone, insulin-like growth factor (IGF)-I, and insulin-like growth factor binding protein (IGFBP)-3 in men. Psychoneuroendocrinology 2000; 25:439-51. [PMID: 10818279 DOI: 10.1016/s0306-4530(99)00069-4] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
The neuroendocrine system is regarded as the major link between the psychological state and the immune system in man. The present study was undertaken to examine the acute effect of ChunDoSunBup Qi-training, a traditional psychosomatic training, on the plasma level of growth hormone (GH), insulin-like growth factor (IGF)-I and insulin like growth factor binding protein (IGFBP)-3 in young men. To characterize the plasma level of hormones and the pattern of IGFBP-3 at pre- (-10 min), mid-time (40 min), and immediately after (post-time, +10 min) Qi-training, radioimmunoassay (RIA) and western ligand blot (WLB) analysis were used. The plasma level of GH at the mid-time was significantly increased (P<0.05) compared to the level at pre-time of Qi-training. The plasma level of IGF-I was also increased at mid-time (P<0.05) and immediately after Qi-training. There was a significant correlation between the levels of GH and IGF-I immediately after Qi-training (r=0.69, P<0.01). In this study, the change of IGFBP-3 among the several IGFBPs was determined. There was a relative shift in IGFBP-3 for the 43-kDa fraction during mid-time of Qi-training (P<0.05). These results suggest that Qi-training influences the growth hormone, IGF-I and IGFBP-3 status via brain-target organ axis in men.
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Affiliation(s)
- H Ryu
- Department of Immunology and Qi (Bioenergy) Medicine, Institute of Biotechnology, Wonkwang University, Iksan, Chonbuk, South Korea.
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Haydar ZR, Blackman MR, Tobin JD, Wright JG, Fleg JL. The relationship between aerobic exercise capacity and circulating IGF-1 levels in healthy men and women. J Am Geriatr Soc 2000; 48:139-45. [PMID: 10682942 DOI: 10.1111/j.1532-5415.2000.tb03904.x] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
OBJECTIVES To determine whether aerobic capacity is associated independently with insulin-like growth factor-I (IGF-1) levels in healthy community-dwelling men and women. SETTING The Baltimore Longitudinal Study on Aging (BLSA). DESIGN A cross-sectional analysis of data from the population-based cohort of the Baltimore Longitudinal Study of Aging (BLSA). PARTICIPANTS We studied 181 men and 92 women aged 20 to 93 years, volunteers in the Baltimore Longitudinal Study on Aging (BLSA). Subjects were free of endocrine, renal, hepatic, gastrointestinal, or cardiac diseases, and they were taking no medications known to interfere with the growth hormone-IGF-1 axis. MEASUREMENTS All subjects underwent a single measurement of serum IGF-1 in the fasting state, as well as peak VO2 determinations during maximal treadmill exercise testing performed within one visit of the IGF-1 determination. Dual energy X-ray absorptiometry (DEXA) scans were performed in a subset of 171 subjects (64 women and 107 men) for determination of fat free mass (FFM). RESULTS In the pooled group of women and men, univariate regression analysis revealed that age was correlated strongly with decreasing IGF-1 levels (r = -0.53, P < .001) and with peak VO2r = -0.56, P < .001). IGF-1 levels were also significantly correlated with peak VO2 (r = 0.29, P < .001). There were no significant gender-related differences in these relationships. On multivariate analysis, age (beta = -0.54, P < .001), but not peak VO2 (P = -0.01, P = .840), remained strongly associated with IGF-1 levels. After adjustment of peak VO2 for FFM in subjects with DEXA scans, results were similar. CONCLUSIONS These findings indicate that although both peak aerobic capacity and circulating IGF-1 levels decline with age, aerobic capacity is not independently related to circulating IGF-1 in healthy men and women across the adult life span.
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Affiliation(s)
- Z R Haydar
- Division of Geriatric Medicine and Gerontology, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
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Bonnefoy M, Kostka T, Patricot MC, Berthouze SE, Mathian B, Lacour JR. Influence of acute and chronic exercise on insulin-like growth factor-I in healthy active elderly men and women. AGING (MILAN, ITALY) 1999; 11:373-9. [PMID: 10738852 DOI: 10.1007/bf03339815] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Abstract
We examined the influence of physical activity (PA) and acute resistance exercise on insulin-like growth factor I (IGF-I) in 39 healthy, independent, community-dwelling elderly volunteers (14 men and 25 women) aged from 66 to 84. In a longitudinal non-interventional study, we compared the fluctuations in IGF-I levels and changes in habitual PA over a 6-month period. PA was evaluated by a questionnaire QAPSE (Questionnaire d'Activité Physique Saint-Etienne), and expressed by two activity indices: mean habitual daily energy expenditure (MHDEE), and daily energy expenditure corresponding to leisure time sports activities (sports activity index). In an experimental design we compared IGF-I levels before, at 1 and 15 minutes after short quadriceps muscle exertion (10 consecutive repetitions) carried out with optimal muscle power development. Changes in IGF-I levels over a 6-month period were positively related to changes in MHDEE (r = 0.41; p<0.01), and sports activity (r = 0.40; p<0.02). When analyzed by gender, these correlations were still statistically significant in women (r = 0.39; p = 0.05 and r = 0.41; p<0.05), but not in men (r = 0.36; p = 0.21 and r = 0.20; p = 0.50). No changes (p = 0.17) were observed in serum IGF-I concentrations after the acute exercise protocol. These findings indicate that IGF-I levels are positively related to fluctuations in habitual PA, at least in women. Further research is needed to establish the best intensity and duration of exercise training to induce these changes.
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Affiliation(s)
- M Bonnefoy
- Service de Médecine Gériatrique, Centre Hospitalier Lyon-Sud, France.
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Scheett TP, Mills PJ, Ziegler MG, Stoppani J, Cooper DM. Effect of exercise on cytokines and growth mediators in prepubertal children. Pediatr Res 1999; 46:429-34. [PMID: 10509363 DOI: 10.1203/00006450-199910000-00011] [Citation(s) in RCA: 52] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Many of the anabolic effects of exercise are mediated through insulin-like growth factor-I (IGF-I), but in adolescents, brief exercise training leads to reductions, rather than the expected increase, in circulating IGF-I. Certain cytokines--interleukin-(IL) 1beta (IL-1beta), IL-6 (IL-6), and tumor necrosis factor-alpha--are increased by exercise in adults and are known to inhibit IGF-I. To test the hypothesis that these cytokines might play a role in the adaptation to exercise, we measured the acute effects of exercise on selected cytokines and growth factors in 17 healthy 8- to 11-y-old children (4 females). Designed to mimic patterns and intensity of exercise found in the real lives of American children, the exercise protocol consisted of a 1.5-h soccer practice (of which about 40 min constituted of vigorous exercise). Pre- and postexercise urine and saliva samples were obtained in all subjects and both blood and urine in nine subjects. The exercise led to significant increases in circulating tumor necrosis factor-alpha (18 +/- 7%, p < 0.05) and IL-6 (125 +/- 35%, p < 0.01) as well as a significant increase in the antiinflammatory cytokine IL-1 receptor antagonist (33 +/- 10%, p < 0.01). Urine levels of IL-6 were also substantially increased by exercise (440 +/- 137%, p < 0.0001). Circulating levels of IGF-I were reduced to a small but significant degree (-6.4 +/- 3.2%, p < 0.05), although IGF-binding protein-1 (known to inhibit IGF-I) was substantially increased (156 +/- 40%, p < 0.001). Cytokines are systemically increased after relatively brief exercise in healthy children. This increase may alter critical anabolic agents such as IGF-I and its binding proteins.
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Affiliation(s)
- T P Scheett
- Department of Pediatrics, University of California, Irvine, College of Medicine, 92697-4475, USA
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Davicco MJ, Horcajada-Molteni MN, Gaumet-Meunier N, Lebecque P, Coxam V, Barlet JP. Endurance training and bone metabolism in middle-aged rats. Mech Ageing Dev 1999; 109:83-96. [PMID: 10515659 DOI: 10.1016/s0047-6374(99)00026-3] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
This study was performed to observe the influence of moderate treadmill running on bone of middle-aged male rats. Seventy 15-month-old Wistar rats were used. Ten initial controls (IC) were killed on day 0. Among the 60 others, three groups of ten exercised rats (E) run 1 h/day, 6 days/week at 60% of their maximum aerobic capacity. On days 30, 60 and 90 of the training period, 20 rats, ten E and ten R (resting animals), were killed. Femoral failure stress never varied and was never different in E and R during the experiment. On day 90 whole body mineral content and mineral density were higher in E than R. Simultaneously, total, diaphyseal and metaphyseal femoral densities were lower in R than IC or than in E. No difference was observed between IC and E. In resting rats, urinary deoxypyridinoline excretion (a marker of bone resorption) increased between days 0 and 90, while it did not change in runners. These results indicate that in middle-aged rats, moderate running prevents decrease in bone mineral density, probably by inhibiting bone resorption.
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Affiliation(s)
- M J Davicco
- Métabolisme Minéral, UMMM, INRA Clermont-Theix, Ceyrat, France
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Abstract
This review summarizes the interactions between GH and exercise. Not only does exercise have profound effects upon the GH/IGF-I axis per se, but there is increasing evidence that such physiological perturbations might be influential in the performance responses to repeated training. However, the effects of systemic administration of rGH in restoring exercise capability and muscle strength in GH deficient adults and the ergogenic benefits of GH doping amongst athletes remain unproven. What is certain is that these issues will be of increasing relevance to clinical endocrinologists.
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Affiliation(s)
- P J Jenkins
- Department of Endocrinology, St Bartholomew's Hospital, London, UK
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Abstract
OBJECTIVE The objective of this study was to examine potential clinical predictors of bone density in patients with eating disorders. METHOD We studied 137 women with anorexia nervosa, bulimia nervosa, or eating disorder not otherwise specified (NOS) after admission to the hospital. Clinical data of patients were collected by clinical interview and standardized questionnaires. Bone mineral density of the lumbar spine was measured by dual energy x-ray absorptiometry. RESULTS Lumbar bone density was significantly correlated to present and past minimum weight even after correction for height and age. Other factors did not reach significance. CONCLUSION Normalized present and past weight is the best predictor of lumbar bone density in patients with eating disorders. Factors like reduced caloric intake, binge eating, vomiting, menstrual status, and use of estrogen, laxatives, and nicotine seem to have no independent effect on bone density in this group of patients.
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Affiliation(s)
- G Goebel
- Klinik Roseneck, Center for Behavioral Medicine, Prien, Germany
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Eliakim A, Brasel JA, Cooper DM. GH response to exercise: assessment of the pituitary refractory period, and relationship with circulating components of the GH-IGF-I axis in adolescent females. J Pediatr Endocrinol Metab 1999; 12:47-55. [PMID: 10392348 DOI: 10.1515/jpem.1999.12.1.47] [Citation(s) in RCA: 14] [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: 11/15/2022]
Abstract
The concept of pituitary refractory period for GH secretion has been previously described. To measure the length of this refractory period we performed an exercise provocation test for GH secretion immediately following multiple overnight GH blood sampling. In addition, we correlated the magnitude of the GH response to a single exercise input with mean overnight GH, IGF-I and circulating IGFBP levels. 23 healthy adolescent females (15-17 yr) performed 10-min constant cycle ergometry at a power normalized to each subject's aerobic and anaerobic capacity. GH was measured every 10 min starting 10 min before exercise and then for 60 min after the exercise bout. Mean nocturnal GH was calculated from overnight values obtained every 20 min over a 12-h period. Pre-exercise GHBP, IGF-I and IGFBPs 1-5 were assessed using standard techniques. In five subjects, a spontaneous GH peak had preceded the exercise test by 1 hour or less, and no response to exercise was found. In the remaining 18 subjects, a GH peak (6.8 +/- 1.3 ng/ml, p < 0.0001) was observed at 32 +/- 4 min after the onset of exercise. The GH response to exercise was not correlated with fitness, mean GH or IGF-I but was correlated with IGFBP-3 (r = 0.65, p < 0.05). Spontaneous GH pulses may acutely render the pituitary refractory to exercise stimuli. The length of this refractory period is approximately 1 hour. The data corroborate the idea that while relationships exist among the various components of the GH-IGF-I axis, no single factor identified to date fully reflects GH-IGF-I "tone".
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Affiliation(s)
- A Eliakim
- Department of Pediatrics, Harbor-UCLA Medical Center, Torrance, USA
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Darling-Raedeke M, Thornton WH, MacDonald RS. Growth hormone and IGF-I plasma concentrations and macronutrient intake measured in a free-living elderly population during a one-year period. J Am Coll Nutr 1998; 17:392-7. [PMID: 9710852 DOI: 10.1080/07315724.1998.10718782] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
OBJECTIVE To determine seasonal variations in circulating concentrations of growth hormone and IGF-I in healthy, free-living elderly and to identify correlates between dietary intake, growth hormone and IGF-I concentrations in this population. METHODS Seven-day diet records and plasma samples were collected throughout a 1-year period. Plasma growth hormone and IGF-I were determined by RIA. Dietary macronutrient intake was determined using Nutritionist IV. RESULTS The dietary intake of the population corresponded to the established recommendations for percentage of fat, carbohydrate and protein. Carbohydrate intake differed significantly during the year, but protein and fat did not. Hormone concentrations were constant throughout the year, with no significant differences observed. No correlation between plasma growth hormone and IGF-I was observed. Growth hormone and IGF-I concentrations did not correlate with macronutrient intake, however subjects with the lowest energy intakes tended to have higher growth hormone and lower IGF-I than those with higher energy intakes. CONCLUSIONS This study provides important information on the dietary intake and hormone concentrations in normal, healthy elderly which will be useful in comparison with persons of similar age with complicating illnesses or nutrient deficiencies.
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Affiliation(s)
- M Darling-Raedeke
- Nutritional Sciences Program, University of Missouri, Columbia 65211, USA
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Eliakim A, Brasel JA, Mohan S, Wong WL, Cooper DM. Increased physical activity and the growth hormone-IGF-I axis in adolescent males. THE AMERICAN JOURNAL OF PHYSIOLOGY 1998; 275:R308-14. [PMID: 9688993 DOI: 10.1152/ajpregu.1998.275.1.r308] [Citation(s) in RCA: 42] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Insulin-like growth factor-I (IGF-I) is associated with muscle hypertrophy, and circulating IGF-I levels are correlated with fitness. To test the hypothesis that IGF-I increases with increased physical activity in adolescent males, 38 subjects (16 +/- 0.7 yr old) were randomized to control (n = 18) or increased physical activity groups for 5 wk. Before and after the intervention, we measured thigh muscle volume using magnetic resonance imaging and serum levels of mean growth hormone (GH) by overnight multiple sampling, GH binding protein (GHBP), IGF-I, and IGFBPs 1-5 by standard assays. Energy expenditure was assessed with the doubly labeled water technique toward the end of the study. In the training subjects there was 1) a significant increase in thigh muscle volume (+3.6 +/- 1%), 2) 15.5 +/- 3.3% greater energy expenditure than in controls, and 3) no evidence of weight loss (+1.44 +/- 0.4%). In contrast to our hypothesis, but similar to our recent observations in adolescent females, training decreased IGF-I (-12 +/- 4%, P < 0. 005). Moreover, training substantially reduced GHBP (-21 +/- 4%, P < 0.00002) and increased IGFBP-2 (+40 +/- 16%, P < 0.008). Brief training increased muscle volume in weight-stable adolescent males and, surprisingly, influenced not only IGF-I but GHBP and IGFBP-2 as well in a manner typically found in energy-deficient states.
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Affiliation(s)
- A Eliakim
- Division of Pediatric Endocrinology, Department of Pediatrics, Harbor-University of California Los Angeles Medical Center, Torrance, California 90509, USA
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Abstract
Genetic factors explain a high proportion of the age-specific differences in bone density, size and turnover. The potential for interaction between hormonal, diet and lifestyle factors is likely to be important. Common allelic variation in the VDR is an example of normal gene variants altering Ca homoeostasis, with effects on body and bone size as well as bone density. The VDR findings suggesting interactions between genetic and nutritional factors are an important target for future research. These studies are complicated by the potential for effects of gene-gene interactions and of undefined environmental factors. These problems notwithstanding, considerations of environmental and nutritional contributions, such as Ca intake and vitamin D status, will be critical in interpreting these genetic pathways and in 'personalizing' nutritional recommendations.
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Affiliation(s)
- J A Eisman
- Bone and Mineral Research Program, Garvan Institute of Medical Research, St Vincent's Hospital, Sydney, NSW, Australia.
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Eliakim A, Brasel JA, Barstow TJ, Mohan S, Cooper DM. Peak oxygen uptake, muscle volume, and the growth hormone-insulin-like growth factor-I axis in adolescent males. Med Sci Sports Exerc 1998; 30:512-7. [PMID: 9565931 DOI: 10.1097/00005768-199804000-00007] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
PURPOSE The growth effects of exercise appear to be mediated in part by central neuroendocrine control reflected in circulating levels of growth hormone (GH), insulin-like growth factor-I (IGF-I), and their binding proteins (BP). In previous studies positive correlations between peak VO2 and circulating IGF-I have been demonstrated. The relationship between peak oxygen uptake and these potential regulating factors has not been examined in adolescent males where patterns of GH pulsatility and levels of IGF-I are rapidly changing. METHODS Forty-three healthy adolescent males (age 16 +/- 0.7 yr, 70% at Tanner V) performed cycle ergometry to determine p oxygen uptake (peak VO2), and magnetic resonance images to determine the thigh muscle volume. Baseline blood samples were collected for GHBP, the extracellular portion of the GH tissue receptor (by ligand mediated immunofunctional assay), IGF-I (by RIA), and IGFBPs 1-5 (by RIA). Mean GH was determined from samples obtained every 20 min overnight. RESULTS Peak VO2/kg was positively correlated with mean overnight GH levels (r = 0.41, P < 0.005). Both peak VO2/kg and thigh muscle volume/kg were negatively correlated with GHBP (r = -0.33, P < 0.02) and IGFBP-4 (r = -0.52, P < 0.005). There were no correlations between peak VO2/kg and IGF-I or IGFBPs 1-3, and 5. CONCLUSIONS GH pulsatility is increased adolescent males who have higher peak VO2, but this did not translate into increases in IGF-I. We speculate that in the fitter males, lower GHBP levels may reduce hepatic sensitivity to GH. Thus, circulating IGF-I was unchanged despite higher mean GH in subjects with higher peak VO2. IGFBP-4 which is known to inhibit IGF-I was negatively correlated with peak VO2 leading, possibly, to increased IGF-I bioactivity. Fitness (as assessed by muscle mass and peak VO2) does modulate the GH-IGF-I axis, but not solely through circulating IGF-I; both GHBP and IGFBPs play important roles.
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Affiliation(s)
- A Eliakim
- Department of Research, Connecticut Children's Medical Center, University of Connecticut, Hartford 06106, USA
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Eisman JA. Vitamin D polymorphisms and calcium homeostasis: a new concept of normal gene variants and physiologic variation. Nutr Rev 1998; 56:s22-9; discussion s54-75. [PMID: 9564174 DOI: 10.1111/j.1753-4887.1998.tb01683.x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Abstract
The initial findings on the vitamin D receptor have opened the field of the genetics of osteoporosis to targeted genetic studies and may open the way to genome scan approaches. Interaction between genetics, the environment, and lifestyle factors will also be an important target for future research. Understanding the physiology of such gene effects will likely open the way to more specific treatments and the selection of more appropriate and effective treatment options.
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Affiliation(s)
- J A Eisman
- Bone and Mineral Research Program, Garvan Institute of Medical Research, St. Vincent's Hospital, Sydney, NSW, Australia
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Bianda T, Glatz Y, Bouillon R, Froesch ER, Schmid C. Effects of short-term insulin-like growth factor-I (IGF-I) or growth hormone (GH) treatment on bone metabolism and on production of 1,25-dihydroxycholecalciferol in GH-deficient adults. J Clin Endocrinol Metab 1998; 83:81-7. [PMID: 9435420 DOI: 10.1210/jcem.83.1.4484] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
UNLABELLED Administration of insulin-like growth factor-I (IGF-I) or growth hormone (GH) is known to stimulate bone turnover and kidney function. To investigate the effects of IGF-I and GH on markers of bone turnover, eight adult GH-deficient patients (48 +/- 14 yr of age) were treated with IGF-I (5 micrograms/kg/h in a continuous s.c. infusion) and GH (0.03 IU/kg/daily s.c. injection at 2000 h) in a randomized cross-over study. We monitored baseline values for three consecutive days before initiating the five-day treatment period, as well as the wash-out period of ten weeks. Serum osteocalcin, carboxyterminal and aminoterminal propeptide of type I procollagen (PICP and PINP, respectively) increased significantly within 2-3 days of both treatments (P < 0.02) and returned to baseline levels within one week after the treatment end. The changes in resorption markers were less marked as compared with formation markers. Total 1,25-dihydroxycholecalciferol (1,25-(OH)2D3) rose significantly, whereas PTH and calcium levels remained unchanged during either treatment. CONCLUSIONS Because the rapid increase in markers of bone formation was not preceded by an increase in resorption markers, IGF-I is likely to stimulate bone formation by a direct effect on osteoblasts. Moreover, because PTH, calcium, and phosphate remained unchanged, IGF-I appears to stimulate renal 1 alpha-hydroxylase activity in vivo.
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Affiliation(s)
- T Bianda
- Division of Endocrinology and Metabolism, University Hospital, Zürich, Switzerland
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