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Aguiar-Oliveira MH, Salvatori R. Disruption of the GHRH receptor and its impact on children and adults: The Itabaianinha syndrome. Rev Endocr Metab Disord 2021; 22:81-89. [PMID: 32935264 DOI: 10.1007/s11154-020-09591-4] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 09/11/2020] [Indexed: 12/22/2022]
Abstract
Since 1994, we have been studying an extended kindred with 105 subjects (over 8 generations) residing in Itabaianinha County, in the Brazilian state of Sergipe, who have severe isolated GH deficiency (IGHD) due to a homozygous inactivating mutation (c.57 + 1G > A) in the GH releasing hormone (GHRH) receptor (GHRHR) gene. Most of these individuals have never received GH replacement therapy. They have low GH, and very low and often undetectable levels of serum IGF-I. Their principal physical findings are proportionate short stature, doll facies, high-pitched-voice, central obesity, wrinkled skin, and youthful hair with delayed pigmentation, and virtual absence of graying. The newborns from this cohort are of normal size, indicating that GH is not needed for intra-uterine growth. However, these IGHD individuals exhibit a myriad of phenotypic changes throughout the body, with a greater number of beneficial than harmful consequences. This GHRH signal disruption syndrome has been a valuable model to study the GH roles in body size and function. This reviews summarized the findings we have reported on this cohort.
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Affiliation(s)
- Manuel H Aguiar-Oliveira
- Division of Endocrinology, University Hospital, Federal University of Sergipe, Rua Claudio Batista s/n, Aracaju, Sergipe, 49060-100, Brazil.
| | - Roberto Salvatori
- Division of Endocrinology, Diabetes and Metabolism, Department of Medicine, The Johns Hopkins University School of Medicine Baltimore, Baltimore, MD, 21287, USA
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Sinha DK, Balasubramanian A, Tatem AJ, Rivera-Mirabal J, Yu J, Kovac J, Pastuszak AW, Lipshultz LI. Beyond the androgen receptor: the role of growth hormone secretagogues in the modern management of body composition in hypogonadal males. Transl Androl Urol 2020; 9:S149-S159. [PMID: 32257855 PMCID: PMC7108996 DOI: 10.21037/tau.2019.11.30] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Male hypogonadism is an increasingly prevalent clinical condition that affects patients’ quality of life and overall health. Obesity and metabolic syndrome can both cause and result from hypogonadism. Although testosterone remains the gold standard for hypogonadism management, its benefits are not always conserved across different populations, especially with regards to changes in body composition. Partially in response to this, growth hormone secretagogues (GHS) have emerged as a potential novel adjunctive therapy for some of the symptoms of hypogonadism, although current data on their clinical efficacy largely remain lacking. The present review examines the existing literature on the use of GHS and explores their potential complementary role in the management of hypogonadal and eugonadal males with metabolic syndrome or subclinical hypogonadism (SH). The GHS that will be discussed include sermorelin, growth hormone-releasing peptides (GHRP)-2, GHRP-6, ibutamoren, and ipamorelin. All are potent GH and IGF-1 stimulators that can significantly improve body composition while ameliorating specific hypogonadal symptoms including fat gain and muscular atrophy. However, a paucity of data examining the clinical effects of these compounds currently limits our understanding of GHS’ role in the treatment of men with hypogonadism, but does open opportunities for future investigation.
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Affiliation(s)
| | | | | | | | - Justin Yu
- Baylor College of Medicine, Houston, TX, USA
| | - Jason Kovac
- Men's Health Center, Urology of Indiana, Greenwood, IN, USA
| | - Alexander W Pastuszak
- Division of Urology, Department of Surgery, University of Utah School of Medicine, Salt Lake City, UT, USA
| | - Larry I Lipshultz
- Scott Department of Urology, Baylor College of Medicine, Houston, TX, USA.,Center for Reproductive Medicine, Baylor College of Medicine, Houston, TX, USA
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Aguiar-Oliveira MH, Bartke A. Growth Hormone Deficiency: Health and Longevity. Endocr Rev 2019; 40:575-601. [PMID: 30576428 PMCID: PMC6416709 DOI: 10.1210/er.2018-00216] [Citation(s) in RCA: 98] [Impact Index Per Article: 19.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/15/2018] [Accepted: 12/07/2018] [Indexed: 12/13/2022]
Abstract
The important role of GH in the control of mammalian longevity was first deduced from extended longevity of mice with genetic GH deficiency (GHD) or GH resistance. Mice with isolated GHD (IGHD) due to GHRH or GHRH receptor mutations, combined deficiency of GH, prolactin, and TSH, or global deletion of GH receptors live longer than do their normal siblings. They also exhibit multiple features of delayed and/or slower aging, accompanied by extension of healthspan. The unexpected, remarkable longevity benefit of severe endocrine defects in these animals presumably represents evolutionarily conserved trade-offs among aging, growth, maturation, fecundity, and the underlying anabolic processes. Importantly, the negative association of GH signaling with longevity extends to other mammalian species, apparently including humans. Data obtained in humans with IGHD type 1B, owing to a mutation of the GHRH receptor gene, in the Itabaianinha County, Brazil, provide a unique opportunity to study the impact of severe reduction in GH signaling on age-related characteristics, health, and functionality. Individuals with IGHD are characterized by proportional short stature, doll facies, high-pitched voices, and central obesity. They have delayed puberty but are fertile and generally healthy. Moreover, these IGHD individuals are partially protected from cancer and some of the common effects of aging and can attain extreme longevity, 103 years of age in one case. We think that low, but detectable, residual GH secretion combined with life-long reduction of circulating IGF-1 and with some tissue levels of IGF-1 and/or IGF-2 preserved may account for the normal longevity and apparent extension of healthspan in these individuals.
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Affiliation(s)
| | - Andrzej Bartke
- Department of Internal Medicine, Southern Illinois University School of Medicine, Springfield, Illinois
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Zhang X, Yang JK, Chen C. Enhanced Pulsatile Growth Hormone Secretion and Altered Metabolic Hormones by in Vivo Hexarelin Treatment in Streptozotocin-Induced Diabetic Rats. Int J Mol Sci 2018; 19:ijms19103067. [PMID: 30297647 PMCID: PMC6213236 DOI: 10.3390/ijms19103067] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2018] [Revised: 09/21/2018] [Accepted: 10/03/2018] [Indexed: 12/30/2022] Open
Abstract
Significant growth hormone (GH) reductions have been reported in diabetic animal models with disturbed metabolic balance coinciding with GH deficiency. Therefore, enhanced GH secretion may have beneficial effects in controlling diabetes. Thus, we aim to investigate the effect of hexarelin, a synthetic GH secretagogue (GHS), on GH secretion in streptozotocin (STZ, 65 mg/kg)-induced diabetic rats. Daily hexarelin (100 μg/kg) treatment was performed for two weeks in four-week-long STZ-diabetic and vehicle control rats. Pulsatile GH secretion in STZ-rats was significantly reduced in total, pulsatile, basal, and mass of GH secretion per burst. In addition, impaired GH secretion was followed by an increase in fasting-level free fatty acids (FFAs) and a decrease in insulin-like growth factor 1 (IGF-1) compared to control rats. After hexarelin treatment, pulsatile GH secretion in STZ-rats was significantly increased in total, pulsatile, and basal, but not in the mass GH secretion per burst, compared to STZ-rats without hexarelin treatment. However, there was no significant elevation in GH secretion in the hexarelin-treated control group. In addition, hexarelin-treated STZ-rats showed a significant decrease in fasting level FFAs, whereas suppression of fasting level for IGF-1 was maintained. These results suggest that STZ-induced diabetic rats have impaired pulsatile GH secretion, causing increased FFAs and decreased IGF-1 levels in circulation. Hexarelin injections for two weeks is able to normalize impaired pulsatile GH secretion with normal fasting levels of FFAs, but fails to recover IGF-1 levels.
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Affiliation(s)
- Xinli Zhang
- School of Biomedical Sciences, University of Queensland, St Lucia, Brisbane, QLD 4072, Australia.
| | - Jin-Kui Yang
- School of Medicine, Faculty of Medicine, Capital Medical University, Beijing 100730, China.
| | - Chen Chen
- School of Biomedical Sciences, University of Queensland, St Lucia, Brisbane, QLD 4072, Australia.
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Sigalos JT, Pastuszak AW. The Safety and Efficacy of Growth Hormone Secretagogues. Sex Med Rev 2018; 6:45-53. [PMID: 28400207 PMCID: PMC5632578 DOI: 10.1016/j.sxmr.2017.02.004] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2016] [Revised: 02/22/2017] [Accepted: 02/24/2017] [Indexed: 12/28/2022]
Abstract
INTRODUCTION Growth hormone (GH) increases lean body mass, decreases fat mass, increases exercise tolerance and maximum oxygen uptake, enhances muscle strength, and improves linear growth. Long-term studies of GH administration offer conflicting results on its safety, which has led to strict Food and Drug Administration criteria for GH use. The potential drawbacks of exogenous GH use are believed to be due in part to impaired regulatory feedback. AIM To review the literature on GH secretagogues (GHSs), which include GH-releasing peptides and the orally available small-molecule drug ibutamoren mesylate. METHODS Review of clinical studies on the safety and efficacy of GHSs in human subjects. MAIN OUTCOME MEASURE Report on the physiologic changes from GHS use in human subjects including its safety profile. RESULTS GHSs promote pulsatile release of GH that is subject to negative feedback and can prevent supra-therapeutic levels of GH and their sequelae. To date, few long-term, rigorously controlled studies have examined the efficacy and safety of GHSs, although GHSs might improve growth velocity in children, stimulate appetite, improve lean mass in wasting states and in obese individuals, decrease bone turnover, increase fat-free mass, and improve sleep. Available studies indicate that GHSs are well tolerated, with some concern for increases in blood glucose because of decreases in insulin sensitivity. CONCLUSION Further work is needed to better understand the long-term impact of GHSs on human anatomy and physiology and more specifically in the context of a diversity of clinical scenarios. Furthermore, the safety of these compounds with long-term use, including evaluation of cancer incidence and mortality, is needed. Sigalos JT, Pastuszak AW. The Safety and Efficacy of Growth Hormone Secretagogues. Sex Med Rev 2018;6:45-53.
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Affiliation(s)
| | - Alexander W Pastuszak
- Center for Reproductive Medicine, Baylor College of Medicine, Houston, TX, USA; Scott Department of Urology, Baylor College of Medicine, Houston, TX, USA.
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Peroni CN, Hayashida CY, Nascimento N, Longuini VC, Toledo RA, Bartolini P, Bowers CY, Toledo SPA. Growth hormone response to growth hormone-releasing peptide-2 in growth hormone-deficient little mice. Clinics (Sao Paulo) 2012; 67:265-72. [PMID: 22473409 PMCID: PMC3297037 DOI: 10.6061/clinics/2012(03)11] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/16/2011] [Accepted: 12/15/2011] [Indexed: 11/18/2022] Open
Abstract
OBJECTIVE To investigate a possible direct, growth hormone-releasing, hormone-independent action of a growth hormone secretagogue, GHRP-2, in pituitary somatotroph cells in the presence of inactive growth hormone-releasing hormone receptors. MATERIALS AND METHODS The responses of serum growth hormone to acutely injected growth hormone-releasing P-2 in lit/lit mice, which represent a model of GH deficiency arising from mutated growth hormone-releasing hormone-receptors, were compared to those observed in the heterozygous (lit/+) littermates and wild-type (+/+) C57BL/6J mice. RESULTS After the administration of 10 mcg of growth hormone-releasing P-2 to lit/lit mice, a growth hormone release of 9.3±1.5 ng/ml was observed compared with 1.04±1.15 ng/ml in controls (p<0.001). In comparison, an intermediate growth hormone release of 34.5±9.7 ng/ml and a higher growth hormone release of 163±46 ng/ml were induced in the lit/+ mice and wild-type mice, respectively. Thus, GHRP-2 stimulated growth hormone in the lit/lit mice, and the release of growth hormone in vivo may be only partially dependent on growth hormone-releasing hormone. Additionally, the plasma leptin and ghrelin levels were evaluated in the lit/lit mice under basal and stimulated conditions. CONCLUSIONS Here, we have demonstrated that lit/lit mice, which harbor a germline mutation in the Growth hormone-releasing hormone gene, maintain a limited but statistically significant growth hormone elevation after exogenous stimulation with GHRP-2. The present data probably reflect a direct, growth hormone-independent effect on Growth hormone S (ghrelin) stimulation in the remaining pituitary somatotrophs of little mice that is mediated by growth hormone S-R 1a.
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Affiliation(s)
- Cibele N Peroni
- Biotechnology Department, National Nuclear Energy Commission, Cidade Universitária, São Paulo, SP, Brazil
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Salvatori R, Serpa MG, Parmigiani G, Britto AVO, Oliveira JLM, Oliveira CRP, Prado CM, Farias CT, Almeida JC, Vicente TAR, Aguiar-Oliveira MH. GH response to hypoglycemia and clonidine in the GH-releasing hormone resistance syndrome. J Endocrinol Invest 2006; 29:805-8. [PMID: 17114911 DOI: 10.1007/bf03347374] [Citation(s) in RCA: 14] [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: 11/30/2022]
Abstract
GH secretion by the pituitary is the result of the balance between the stimulatory effect of GHRH and the inhibitory effect of SS. Patients with mutations in GHRH receptor (GHRH-R) gene (GHRH-R) offer a unique model to study the mechanism of action of different GH secretion stimuli. In the past, we have demonstrated a small but significant GH response to a GH secretagogue (GHRP-2) in a homogenous cohort of patients with severe GH deficiency (GHD) due to a homozygous null mutation in GHRH-R (IVS1+1G-->A). Now, we sought to determine if we could detect a GH response to hypoglycemia (ITT: insulin tolerance test) or clonidine (CL) in these patients. Nine young GHD subjects underwent both ITT and CL tests, and 2 additional subjects underwent only CL test. There was a small but significant GH increase during ITT, but not during CL test. These results indicate that a minimal albeit significant GH response to ITT can occur despite complete lack of GHRH-R function.
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Affiliation(s)
- R Salvatori
- Division of Endocrinology, Department of Medicine, The Johns Hopkins University School of Medicine, Baltimore, MD 21287, USA.
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Affiliation(s)
- Roberto Salvatori
- Department of Medicine, Division of Endocrinology, Johns Hopkins University School of Medicine, Baltimore MD 21287, USA.
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