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Li W, Li H, Hu Q, Wang L, Yin Z, Hu G. IGFBP1a is a nutrient deficient response factor that can inhibit fish reproduction through the hypothalamus-pituitary-ovary axis†. Biol Reprod 2024; 110:761-771. [PMID: 38374691 DOI: 10.1093/biolre/ioae009] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2023] [Revised: 11/27/2023] [Accepted: 01/09/2024] [Indexed: 02/21/2024] Open
Abstract
Reproduction is a high energy consuming process, so long-term malnutrition can significantly inhibit gonadal development. However, little is known about the molecular mechanism by which fasting inhibits reproduction. Our present study found that fasting could dramatically induce insulin-like growth factor binding protein 1 (IGFBP1) expression in the liver, hypothalamus, pituitary and ovaries of grass carp. In addition, IGFBP1a in the hypothalamus-pituitary-gonad axis could inhibit the development of gonads. These results indicated that fasting may participate in the regulation of fish gonadal development through the mediation of IGFBP1a. Further studies found that IGFBP1a could markedly inhibit gonadotropin-releasing hormone 3 expressions in hypothalamus cells. At the pituitary level, IGFBP1a could significantly reduce the gonadotropin hormones (LH and FSH) expression by blocking the action of pituitary insulin-like growth factor 1. Interestingly, IGFBP1a could also directly inhibit the expression of lhr, fshr, and sex steroid hormone synthase genes (cyp11a, cyp17a, and cyp19a1) in the ovary. These results indicated that IGFBP1a should be a nutrient deficient response factor that could inhibit fish reproduction through the hypothalamus-pituitary-ovary axis.
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Affiliation(s)
- Wei Li
- Hubei Hongshan Laboratory, College of Fisheries, Huazhong Agricultural University, Wuhan, China
| | - Hangyu Li
- Hubei Hongshan Laboratory, College of Fisheries, Huazhong Agricultural University, Wuhan, China
| | - Qiongyao Hu
- Hubei Hongshan Laboratory, College of Fisheries, Huazhong Agricultural University, Wuhan, China
| | - Linlin Wang
- Hubei Hongshan Laboratory, College of Fisheries, Huazhong Agricultural University, Wuhan, China
| | - Zhan Yin
- State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, China
| | - Guangfu Hu
- Hubei Hongshan Laboratory, College of Fisheries, Huazhong Agricultural University, Wuhan, China
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Sheep as a model for neuroendocrinology research. PROGRESS IN MOLECULAR BIOLOGY AND TRANSLATIONAL SCIENCE 2022; 189:1-34. [PMID: 35595346 DOI: 10.1016/bs.pmbts.2022.01.001] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Animal models remain essential to understand the fundamental mechanisms of physiology and pathology. Particularly, the complex and dynamic nature of neuroendocrine cells of the hypothalamus make them difficult to study. The neuroendocrine systems of the hypothalamus are critical for survival and reproduction, and are highly conserved throughout vertebrate evolution. Their roles in controlling body metabolism, growth and body composition, stress, electrolyte balance, and reproduction, have been intensively studied, and have yielded groundbreaking discoveries. Many of these discoveries would not have been feasible without the use of the domestic sheep (Ovis aries). The sheep has been used for decades to study the neuroendocrine systems of the hypothalamus and has become a model for human neuroendocrinology. The aim of this chapter is to review some of the profound biomedical discoveries made possible by the use of sheep. The advantages and limitations of sheep as a neuroendocrine model will be discussed. While no animal model can perfectly recapitulate a human disease or condition, sheep are invaluable for enabling manipulations not possible in human subjects and isolating physiologic variables to garner insight into neuroendocrinology and associated pathologies.
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Foradori CD, Whitlock BK, Daniel JA, Zimmerman AD, Jones MA, Read CC, Steele BP, Smith JT, Clarke IJ, Elsasser TH, Keisler DH, Sartin JL. Kisspeptin Stimulates Growth Hormone Release by Utilizing Neuropeptide Y Pathways and Is Dependent on the Presence of Ghrelin in the Ewe. Endocrinology 2017; 158:3526-3539. [PMID: 28977590 DOI: 10.1210/en.2017-00303] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/29/2017] [Accepted: 07/13/2017] [Indexed: 12/31/2022]
Abstract
Although kisspeptin is the primary stimulator of gonadotropin-releasing hormone secretion and therefore the hypothalamic-pituitary-gonadal axis, recent findings suggest kisspeptin can also regulate additional neuroendocrine processes including release of growth hormone (GH). Here we show that central delivery of kisspeptin causes a robust rise in plasma GH in fasted but not fed sheep. Kisspeptin-induced GH secretion was similar in animals fasted for 24 hours and those fasted for 72 hours, suggesting that the factors involved in kisspeptin-induced GH secretion are responsive to loss of food availability and not the result of severe negative energy balance. Pretreatment with the neuropeptide Y (NPY) Y1 receptor antagonist, BIBO 3304, blocked the effects of kisspeptin-induced GH release, implicating NPY as an intermediary. Kisspeptin treatment induced c-Fos in NPY and GH-releasing hormone (GHRH) cells of the arcuate nucleus. The same kisspeptin treatment resulted in a reduction in c-Fos in somatostatin (SS) cells in the periventricular nucleus. Finally, blockade of systemic ghrelin release or antagonism of the ghrelin receptor eliminated or reduced the ability of kisspeptin to induce GH release, suggesting the presence of ghrelin is required for kisspeptin-induced GH release in fasted animals. Our findings support the hypothesis that during short-term fasting, systemic ghrelin concentrations and NPY expression in the arcuate nucleus rise. This permits kisspeptin activation of NPY cells. In turn, NPY stimulates GHRH cells and inhibits SS cells, resulting in GH release. We propose a mechanism by which kisspeptin conveys reproductive and hormone status onto the somatotropic axis, resulting in alterations in GH release.
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Affiliation(s)
- Chad D Foradori
- Department of Anatomy, Physiology & Pharmacology, Auburn University, Auburn, Alabama 36849
| | - Brian K Whitlock
- Department of Large Animal Clinical Sciences, University of Tennessee, Knoxville, Tennessee 37996
| | - Jay A Daniel
- Department of Animal Science, Berry College, Mt. Berry, Georgia 30149
| | - Arthur D Zimmerman
- Department of Anatomy, Physiology & Pharmacology, Auburn University, Auburn, Alabama 36849
| | - Melaney A Jones
- Department of Anatomy, Physiology & Pharmacology, Auburn University, Auburn, Alabama 36849
| | - Casey C Read
- Department of Anatomy, Physiology & Pharmacology, Auburn University, Auburn, Alabama 36849
| | - Barbara P Steele
- Department of Anatomy, Physiology & Pharmacology, Auburn University, Auburn, Alabama 36849
| | - Jeremy T Smith
- School of Anatomy, Physiology and Human Biology, University of Western Australia, Perth, Crawley, Washington 6009, Australia
| | - Iain J Clarke
- Neuroscience Program, Monash Biomedicine Discovery Institute and Department of Physiology, Monash University, Melbourne, Victoria 3800, Australia
| | - Theodore H Elsasser
- Animal Genomics and Improvement Laboratory, US Department of Agriculture, Agricultural Research Service, Beltsville, Maryland 20705
| | - Duane H Keisler
- Division of Animal Sciences, University of Missouri, Columbia, Missouri 65211
| | - James L Sartin
- Department of Anatomy, Physiology & Pharmacology, Auburn University, Auburn, Alabama 36849
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Sasanuma H, Nakata M, Parmila K, Nakae J, Yada T. PDK1-FoxO1 pathway in AgRP neurons of arcuate nucleus promotes bone formation via GHRH-GH-IGF1 axis. Mol Metab 2017; 6:428-439. [PMID: 28462077 PMCID: PMC5404105 DOI: 10.1016/j.molmet.2017.02.003] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/01/2017] [Accepted: 02/11/2017] [Indexed: 01/13/2023] Open
Abstract
Objective In the hypothalamic arcuate nucleus (ARC), orexigenic agouti-related peptide (AgRP) neurons regulate feeding behavior and energy homeostasis, functions connected to bone metabolism. The 3-phosphoinositide-dependent protein kinase-1 (PDK1) serves as a major signaling molecule particularly for leptin and insulin in AgRP neurons. We asked whether PDK1 in AGRP neurons also contributes to bone metabolism. Methods We generated AgRP neuron-specific PDK1 knockout (Agrp Pdk1−/−) mice and those with additional AgRP neuron-specific expression of transactivation-defective FoxO1 (Agrp Pdk1−/−Δ256Foxo1). Bone metabolism in KO and WT mice was analyzed by quantitative computed tomography (QCT), bone histomorphometry, measurement of plasma biomarkers, and qPCR analysis of peptides. Results In Agrp Pdk1−/− female mice aged 6 weeks, compared with Agrp Cre mice, both stature and femur length were shorter while body weight was unchanged. Cortical bone mineral density (BMD) and cancellous BMD in the femur decreased, and bone formation was delayed. Furthermore, plasma GH and IGF-1 levels were reduced in parallel with decreased mRNA expressions for GH in pituitary and GHRH in ARC. Osteoblast activity was suppressed and osteoclast activity was enhanced. These changes in stature, BMD and GH level were rescued in Agrp Pdk1−/−Δ256Foxo1 mice, suggesting that the bone abnormalities and impaired GH release were mediated by enhanced Foxo1 due to deletion of PDK1. Conclusions This study reveals a novel role of PDK1-Foxo1 pathway of AgRP neurons in controlling bone metabolism primarily via GHRH-GH-IGF-1 axis. Agrp neuron-selective Pdk1 knockout mice exhibit short stature, shortened limbs and decreased bone density in both cortical and cancellous bones. In Agrp Pdk1 knockout mice, GHRH-GH-IGF1 axis was markedly down-regulated. Retarded bone growth and reduced GH in Agrp Pdk1 knockout mice were rescued by additional expression of dominant negative FoxO1 in AgRP neurons. Pdk1-FoxO1 signaling in AgRP neurons is linked to regulation of GHRH-GH-IGF1 axis and bone metabolism.
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Affiliation(s)
- Hideyuki Sasanuma
- Department of Physiology, Division of Integrative Physiology, Jichi Medical University, 3311-1 Yakushiji, Tochigi, Shimotsuke, 329-0498, Japan; Department of Orthopaedic Surgery, Faculty of Medicine, Jichi Medical University, 3311-1 Yakushiji, Tochigi, Shimotsuke, 329-0498, Japan
| | - Masanori Nakata
- Department of Physiology, Division of Integrative Physiology, Jichi Medical University, 3311-1 Yakushiji, Tochigi, Shimotsuke, 329-0498, Japan.
| | - Kumari Parmila
- Department of Physiology, Division of Integrative Physiology, Jichi Medical University, 3311-1 Yakushiji, Tochigi, Shimotsuke, 329-0498, Japan
| | - Jun Nakae
- Frontier Medicine on Metabolic Syndrome, Division of Endocrinology, Metabolism and Nephrology, Department of Internal Medicine, Keio University School of Medicine, Tokyo, Japan
| | - Toshihiko Yada
- Department of Physiology, Division of Integrative Physiology, Jichi Medical University, 3311-1 Yakushiji, Tochigi, Shimotsuke, 329-0498, Japan.
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Steyn FJ, Tolle V, Chen C, Epelbaum J. Neuroendocrine Regulation of Growth Hormone Secretion. Compr Physiol 2016; 6:687-735. [PMID: 27065166 DOI: 10.1002/cphy.c150002] [Citation(s) in RCA: 71] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
This article reviews the main findings that emerged in the intervening years since the previous volume on hormonal control of growth in the section on the endocrine system of the Handbook of Physiology concerning the intra- and extrahypothalamic neuronal networks connecting growth hormone releasing hormone (GHRH) and somatostatin hypophysiotropic neurons and the integration between regulators of food intake/metabolism and GH release. Among these findings, the discovery of ghrelin still raises many unanswered questions. One important event was the application of deconvolution analysis to the pulsatile patterns of GH secretion in different mammalian species, including Man, according to gender, hormonal environment and ageing. Concerning this last phenomenon, a great body of evidence now supports the role of an attenuation of the GHRH/GH/Insulin-like growth factor-1 (IGF-1) axis in the control of mammalian aging.
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Affiliation(s)
- Frederik J Steyn
- University of Queensland Centre for Clinical Research and the School of Biomedical Sciences, University of Queensland, St. Lucia, Brisbane, Queensland, Australia
| | - Virginie Tolle
- Unité Mixte de Recherche en Santé 894 INSERM, Centre de Psychiatrie et Neurosciences, Université Paris Descartes, Sorbonne Paris Cité, Paris, France
| | - Chen Chen
- School of Biomedical Sciences, University of Queensland, St. Lucia, Brisbane, Queensland, Australia
| | - Jacques Epelbaum
- University of Queensland Centre for Clinical Research and the School of Biomedical Sciences, University of Queensland, St. Lucia, Brisbane, Queensland, Australia
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6
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Fernando HA, Zibellini J, Hsu MS, Seimon RV, Nguyen AD, Sainsbury A. The neuropeptide Y-ergic system: potential therapeutic target against bone loss with obesity treatments. Expert Rev Endocrinol Metab 2015; 10:177-191. [PMID: 30293515 DOI: 10.1586/17446651.2015.1001741] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
Obesity is no longer considered to provide protection against osteoporosis. Moreover, treatments for obesity are now suspected of reducing bone mass. With the escalating incidence of obesity, combined with increases in the frequency, duration and intensity of interventions used to combat it, we face a potential increase in health burden due to osteoporotic fractures. The neuropeptide Y-ergic system offers a potential target for the prevention and anabolic treatment of bone loss in obesity, due to its dual role in the regulation of energy homeostasis and bone mass. Although the strongest stimulation of bone mass by this system appears to occur via indirect hypothalamic pathways involving Y2 receptors (one of the five types of receptors for neuropeptide Y), Y1 receptors on osteoblasts (bone-forming cells) induce direct effects to enhance bone mass. This latter pathway may offer a suitable target for anti-osteoporotic treatment while also minimizing the risk of adverse side effects.
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Affiliation(s)
- Hamish A Fernando
- a 1 The Boden Institute of Obesity, Nutrition, Exercise & Eating Disorders, Sydney Medical School, The University of Sydney, Camperdown NSW 2006, Australia
| | - Jessica Zibellini
- a 1 The Boden Institute of Obesity, Nutrition, Exercise & Eating Disorders, Sydney Medical School, The University of Sydney, Camperdown NSW 2006, Australia
| | - Michelle Sh Hsu
- a 1 The Boden Institute of Obesity, Nutrition, Exercise & Eating Disorders, Sydney Medical School, The University of Sydney, Camperdown NSW 2006, Australia
| | - Radhika V Seimon
- a 1 The Boden Institute of Obesity, Nutrition, Exercise & Eating Disorders, Sydney Medical School, The University of Sydney, Camperdown NSW 2006, Australia
| | - Amy D Nguyen
- b 2 Neuroscience Program, Garvan Institute of Medical Research, University of New South Wales, Darlinghurst, Australia
| | - Amanda Sainsbury
- a 1 The Boden Institute of Obesity, Nutrition, Exercise & Eating Disorders, Sydney Medical School, The University of Sydney, Camperdown NSW 2006, Australia
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Actions of NPY, and its Y1 and Y2 receptors on pulsatile growth hormone secretion during the fed and fasted state. J Neurosci 2015; 34:16309-19. [PMID: 25471570 DOI: 10.1523/jneurosci.4622-13.2014] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
The hypothalamic NPY system plays an important role in regulating food intake and energy expenditure. Different biological actions of NPY are assigned to NPY receptor subtypes. Recent studies demonstrated a close relationship between food intake and growth hormone (GH) secretion; however, the mechanism through which endogenous NPY modulates GH release remains unknown. Moreover, conclusive evidence demonstrating a role for NPY and Y-receptors in regulating the endogenous pulsatile release of GH does not exist. We used genetically modified mice (germline Npy, Y1, and Y2 receptor knock-out mice) to assess pulsatile GH secretion under both fed and fasting conditions. Deletion of NPY did not impact fed GH release; however, it reversed the fasting-induced suppression of pulsatile GH secretion. The recovery of GH secretion was associated with a reduction in hypothalamic somatotropin release inhibiting factor (Srif; somatostatin) mRNA expression. Moreover, observations revealed a differential role for Y1 and Y2 receptors, wherein the postsynaptic Y1 receptor suppresses GH secretion in fasting. In contrast, the presynaptic Y2 receptor maintains normal GH output under long-term ad libitum-fed conditions. These data demonstrate an integrated neural circuit that modulates GH release relative to food intake, and provide essential information to address the differential roles of Y1 and Y2 receptors in regulating the release of GH under fed and fasting states.
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Fang XL, Zhu XT, Chen SF, Zhang ZQ, Zeng QJ, Deng L, Peng JL, Yu JJ, Wang LN, Wang SB, Gao P, Jiang QY, Shu G. Differential gene expression pattern in hypothalamus of chickens during fasting-induced metabolic reprogramming: Functions of glucose and lipid metabolism in the feed intake of chickens. Poult Sci 2014; 93:2841-54. [DOI: 10.3382/ps.2014-04047] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
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9
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Roa J, Herbison AE. Direct regulation of GnRH neuron excitability by arcuate nucleus POMC and NPY neuron neuropeptides in female mice. Endocrinology 2012; 153:5587-99. [PMID: 22948210 DOI: 10.1210/en.2012-1470] [Citation(s) in RCA: 118] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Hypothalamic neuropeptide Y (NPY) and proopiomelanocortin (POMC) neurons act to sense and coordinate the brain's responses to metabolic cues. One neuronal network that is very sensitive to metabolic status is that controlling fertility. In this study, we investigated the impact of neuropeptides released by NPY and POMC neurons on the cellular excitability of GnRH neurons, the final output cells of the brain controlling fertility. The majority (∼70%) of GnRH neurons were activated by α-melanocyte-stimulating hormone, and this resulted from the direct postsynaptic activation of melanocortin receptor 3 and melanocortin receptor 4. A small population of GnRH neurons (∼15%) was excited by cocaine and amphetamine-regulated transcript or inhibited by β-endorphin. Agouti-related peptide, released by NPY neurons, was found to have variable inhibitory (∼10%) and stimulatory (∼25%) effects upon subpopulations of GnRH neurons. A variety of NPY and pancreatic polypeptide analogs was used to examine potential NPY interactions with GnRH neurons. Although porcine NPY (Y1/Y2/Y5 agonist) directly inhibited the firing of approximately 45% of GnRH neurons, [Leu(31),Pro(34)]-NPY (Y1/Y4/Y5 agonist) could excite (56%) or inhibit (19%). Experiments with further agonists indicated that Y1 receptors were responsible for suppressing GnRH neuron activity, whereas postsynaptic Y4 receptors were stimulatory. These results show that the activity of GnRH neurons is regulated in a complex manner by neuropeptides released by POMC and NPY neurons. This provides a direct route through which different metabolic cues can regulate fertility.
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Affiliation(s)
- Juan Roa
- Centre for Neuroendocrinology, Department of Physiology, University of Otago School of Medical Sciences, Dunedin, New Zealand
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Sainsbury A, Zhang L. Role of the hypothalamus in the neuroendocrine regulation of body weight and composition during energy deficit. Obes Rev 2012; 13:234-57. [PMID: 22070225 DOI: 10.1111/j.1467-789x.2011.00948.x] [Citation(s) in RCA: 59] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Energy deficit in lean or obese animals or humans stimulates appetite, reduces energy expenditure and possibly also decreases physical activity, thereby contributing to weight regain. Often overlooked in weight loss trials for obesity, however, is the effect of energy restriction on neuroendocrine status. Negative energy balance in lean animals and humans consistently inhibits activity of the hypothalamo-pituitary-thyroid, -gonadotropic and -somatotropic axes (or reduces circulating insulin-like growth factor-1 levels), while concomitantly activating the hypothalamo-pituitary-adrenal axis, with emerging evidence of similar changes in overweight and obese people during lifestyle interventions for weight loss. These neuroendocrine changes, which animal studies show may result in part from hypothalamic actions of orexigenic (e.g. neuropeptide Y, agouti-related peptide) and anorexigenic peptides (e.g. alpha-melanocyte-stimulating hormone, and cocaine and amphetamine-related transcript), can adversely affect body composition by promoting the accumulation of adipose tissue (particularly central adiposity) and stimulating the loss of lean body mass and bone. As such, current efforts to maximize loss of excess body fat in obese people may inadvertently be promoting long-term complications such as central obesity and associated health risks, as well as sarcopenia and osteoporosis. Future weight loss trials would benefit from assessment of the effects on body composition and key hormonal regulators of body composition using sensitive techniques.
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Affiliation(s)
- A Sainsbury
- Neuroscience Research Program, Garvan Institute of Medical Research, Sydney, NSW, Australia.
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Yulyaningsih E, Zhang L, Herzog H, Sainsbury A. NPY receptors as potential targets for anti-obesity drug development. Br J Pharmacol 2011; 163:1170-202. [PMID: 21545413 DOI: 10.1111/j.1476-5381.2011.01363.x] [Citation(s) in RCA: 102] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
The neuropeptide Y system has proven to be one of the most important regulators of feeding behaviour and energy homeostasis, thus presenting great potential as a therapeutic target for the treatment of disorders such as obesity and at the other extreme, anorexia. Due to the initial lack of pharmacological tools that are active in vivo, functions of the different Y receptors have been mainly studied in knockout and transgenic mouse models. However, over recent years various Y receptor selective peptidic and non-peptidic agonists and antagonists have been developed and tested. Their therapeutic potential in relation to treating obesity and other disorders of energy homeostasis is discussed in this review.
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Affiliation(s)
- Ernie Yulyaningsih
- Neuroscience Research Program, Garvan Institute of Medical Research, St Vincent's Hospital, Darlinghurst, Sydney, NSW, Australia
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12
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The neuropeptide Y system: Pathophysiological and therapeutic implications in obesity and cancer. Pharmacol Ther 2011; 131:91-113. [DOI: 10.1016/j.pharmthera.2011.03.011] [Citation(s) in RCA: 131] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2011] [Accepted: 03/07/2011] [Indexed: 12/28/2022]
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13
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Zhang L, Riepler SJ, Turner N, Enriquez RF, Lee ICJ, Baldock PA, Herzog H, Sainsbury A. Y2 and Y4 receptor signaling synergistically act on energy expenditure and physical activity. Am J Physiol Regul Integr Comp Physiol 2010; 299:R1618-28. [DOI: 10.1152/ajpregu.00345.2010] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Neuropeptide Y receptors are critical regulators of energy homeostasis and are well known for their powerful influence on feeding, but their roles in other important aspects of energy homeostasis, such as energy expenditure and their functional interactions in these processes, are largely unknown. Here we show that mice lacking both Y2 and Y4 receptors exhibited a reduction in adiposity, more prominent in intra-abdominal vs. subcutaneous fat, and an increase in lean mass as determined by dual-energy X-ray absorptiometry. These changes were more pronounced than those seen in mice with Y2 or Y4 receptor single deletion, demonstrating the important roles and synergy of Y2 and Y4 signaling in the regulation of body composition. These changes in body composition occurred without significant changes in food intake, but energy expenditure and physical activity were significantly increased in Y4−/− and particularly in Y2−/−Y4−/− but not in Y2−/− mice, suggesting a critical role of Y4 signaling and synergistic interactions with Y2 signaling in the regulation of energy expenditure and physical activity. Y2−/− and Y4−/− mice also exhibited a decrease in respiratory exchange ratio with no further synergistic decrease in Y2−/−Y4−/− mice, suggesting that Y2 and Y4 signaling each play important and independent roles in the regulation of substrate utilization. The synergy between Y2 and Y4 signaling in regulating fat mass may be related to differences in mitochondrial oxidative capacity, since Y2−/−Y4−/− but not Y2−/− or Y4−/− mice showed significant increases in muscle protein levels of peroxisome proliferator-activated receptor (PPAR)γ coactivator (PGC)-1α, and mitochondrial respiratory chain complexes I and III. Taken together, this work demonstrates the critical roles of Y2 and Y4 receptors in the regulation of body composition and energy metabolism, highlighting dual antagonism of Y2 and Y4 receptors as a potentially effective anti-obesity treatment.
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Affiliation(s)
| | | | - Nigel Turner
- Diabetes and Obesity Program, Garvan Institute of Medical Research, St. Vincent's Hospital, Darlinghurst, Sydney, Australia
- St. Vincent's Hospital Clinical School,
| | | | | | | | - Herbert Herzog
- Neuroscience Research Program and
- Faculty of Medicine, University of New South Wales, Sydney, Australia
| | - Amanda Sainsbury
- Neuroscience Research Program and
- School of Medical Sciences, and
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14
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Colledge WH, Mei H, d'Anglemont de Tassigny X. Mouse models to study the central regulation of puberty. Mol Cell Endocrinol 2010; 324:12-20. [PMID: 20083157 DOI: 10.1016/j.mce.2010.01.015] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/22/2009] [Revised: 01/11/2010] [Accepted: 01/12/2010] [Indexed: 01/08/2023]
Abstract
At puberty, the mammalian reproductive axis is activated by neuroendocrine events within the hypothalamus that initiate pulsatile secretion of gonadotropin releasing hormone (GnRH) to activate the pituitary/gonadal axis. Thus, puberty is critically dependent on the integrity of GnRH neuronal activity. Defects in the migration of GnRH neurons into the forebrain during development or in GnRH synthesis or release prevent pubertal maturation of the reproductive axis. Both naturally occurring and genetically modified mutant mice have provided valuable information about the cellular and molecular events required for normal pubertal development. This review focuses specifically on the molecules that have been identified from studies in mutant mice that act centrally to control entry into puberty.
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Affiliation(s)
- William H Colledge
- Reproductive Physiology Group, Department of Physiology, Development and Neuroscience, University of Cambridge, Downing Street, Cambridge CB2 3EG, UK.
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15
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Shi YC, Lin S, Wong IPL, Baldock PA, Aljanova A, Enriquez RF, Castillo L, Mitchell NF, Ye JM, Zhang L, Macia L, Yulyaningsih E, Nguyen AD, Riepler SJ, Herzog H, Sainsbury A. NPY neuron-specific Y2 receptors regulate adipose tissue and trabecular bone but not cortical bone homeostasis in mice. PLoS One 2010; 5:e11361. [PMID: 20613867 PMCID: PMC2894044 DOI: 10.1371/journal.pone.0011361] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2010] [Accepted: 06/01/2010] [Indexed: 12/22/2022] Open
Abstract
BACKGROUND Y2 receptor signalling is known to be important in neuropeptide Y (NPY)-mediated effects on energy homeostasis and bone physiology. Y2 receptors are located post-synaptically as well as acting as auto receptors on NPY-expressing neurons, and the different roles of these two populations of Y2 receptors in the regulation of energy homeostasis and body composition are unclear. METHODOLOGY/PRINCIPAL FINDINGS We thus generated two conditional knockout mouse models, Y2(lox/lox) and NPYCre/+;Y2(lox/lox), in which Y2 receptors can be selectively ablated either in the hypothalamus or specifically in hypothalamic NPY-producing neurons of adult mice. Specific deletion of hypothalamic Y2 receptors increases food intake and body weight compared to controls. Importantly, specific ablation of hypothalamic Y2 receptors on NPY-containing neurons results in a significantly greater adiposity in female but not male mice, accompanied by increased hepatic triglyceride levels, decreased expression of liver carnitine palmitoyltransferase (CPT1) and increased expression of muscle phosphorylated acetyl-CoA carboxylase (ACC). While food intake, body weight, femur length, bone mineral content, density and cortical bone volume and thickness are not significantly altered, trabecular bone volume and number were significantly increased by hypothalamic Y2 deletion on NPY-expressing neurons. Interestingly, in situ hybridisation reveals increased NPY and decreased proopiomelanocortin (POMC) mRNA expression in the arcuate nucleus of mice with hypothalamus-specific deletion of Y2 receptors in NPY neurons, consistent with a negative feedback mechanism between NPY expression and Y2 receptors on NPY-ergic neurons. CONCLUSIONS/SIGNIFICANCE Taken together these data demonstrate the anti-obesogenic role of Y2 receptors in the brain, notably on NPY-ergic neurons, possibly via inhibition of NPY neurons and concomitant stimulation of POMC-expressing neurons in the arcuate nucleus of the hypothalamus, reducing lipogenic pathways in liver and/or skeletal muscle in females. These data also reveal as an anti-osteogenic effect of Y2 receptors on hypothalamic NPY-expressing neurons on trabecular but not on cortical bone.
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Affiliation(s)
- Yan-Chuan Shi
- Neuroscience Research Program, Garvan Institute of Medical Research, Sydney, New South Wales, Australia
| | - Shu Lin
- Neuroscience Research Program, Garvan Institute of Medical Research, Sydney, New South Wales, Australia
| | - Iris P. L. Wong
- Neuroscience Research Program, Garvan Institute of Medical Research, Sydney, New South Wales, Australia
| | - Paul A. Baldock
- Neuroscience Research Program, Garvan Institute of Medical Research, Sydney, New South Wales, Australia
- Faculty of Medicine, University of New South Wales, Sydney, New South Wales, Australia
| | - Aygul Aljanova
- Neuroscience Research Program, Garvan Institute of Medical Research, Sydney, New South Wales, Australia
| | - Ronaldo F. Enriquez
- Neuroscience Research Program, Garvan Institute of Medical Research, Sydney, New South Wales, Australia
| | - Lesley Castillo
- Neuroscience Research Program, Garvan Institute of Medical Research, Sydney, New South Wales, Australia
| | - Natalie F. Mitchell
- Neuroscience Research Program, Garvan Institute of Medical Research, Sydney, New South Wales, Australia
| | - Ji-Ming Ye
- Diabetes and Obesity Research Program, Garvan Institute of Medical Research, Sydney, New South Wales, Australia
| | - Lei Zhang
- Neuroscience Research Program, Garvan Institute of Medical Research, Sydney, New South Wales, Australia
| | - Laurence Macia
- Neuroscience Research Program, Garvan Institute of Medical Research, Sydney, New South Wales, Australia
| | - Ernie Yulyaningsih
- Neuroscience Research Program, Garvan Institute of Medical Research, Sydney, New South Wales, Australia
| | - Amy D. Nguyen
- Neuroscience Research Program, Garvan Institute of Medical Research, Sydney, New South Wales, Australia
| | - Sabrina J. Riepler
- Neuroscience Research Program, Garvan Institute of Medical Research, Sydney, New South Wales, Australia
| | - Herbert Herzog
- Neuroscience Research Program, Garvan Institute of Medical Research, Sydney, New South Wales, Australia
- Faculty of Medicine, University of New South Wales, Sydney, New South Wales, Australia
| | - Amanda Sainsbury
- Neuroscience Research Program, Garvan Institute of Medical Research, Sydney, New South Wales, Australia
- School of Medical Sciences, University of New South Wales, Sydney, New South Wales, Australia
- * E-mail:
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16
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Osterstock G, Escobar P, Mitutsova V, Gouty-Colomer LA, Fontanaud P, Molino F, Fehrentz JA, Carmignac D, Martinez J, Guerineau NC, Robinson ICAF, Mollard P, Méry PF. Ghrelin stimulation of growth hormone-releasing hormone neurons is direct in the arcuate nucleus. PLoS One 2010; 5:e9159. [PMID: 20161791 PMCID: PMC2820089 DOI: 10.1371/journal.pone.0009159] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2009] [Accepted: 01/08/2010] [Indexed: 11/26/2022] Open
Abstract
Background Ghrelin targets the arcuate nucleus, from where growth hormone releasing hormone (GHRH) neurones trigger GH secretion. This hypothalamic nucleus also contains neuropeptide Y (NPY) neurons which play a master role in the effect of ghrelin on feeding. Interestingly, connections between NPY and GHRH neurons have been reported, leading to the hypothesis that the GH axis and the feeding circuits might be co-regulated by ghrelin. Principal Findings Here, we show that ghrelin stimulates the firing rate of identified GHRH neurons, in transgenic GHRH-GFP mice. This stimulation is prevented by growth hormone secretagogue receptor-1 antagonism as well as by U-73122, a phospholipase C inhibitor and by calcium channels blockers. The effect of ghrelin does not require synaptic transmission, as it is not antagonized by γ-aminobutyric acid, glutamate and NPY receptor antagonists. In addition, this hypothalamic effect of ghrelin is independent of somatostatin, the inhibitor of the GH axis, since it is also found in somatostatin knockout mice. Indeed, ghrelin does not modify synaptic currents of GHRH neurons. However, ghrelin exerts a strong and direct depolarizing effect on GHRH neurons, which supports their increased firing rate. Conclusion Thus, GHRH neurons are a specific target for ghrelin within the brain, and not activated secondary to altered activity in feeding circuits. These results support the view that ghrelin related therapeutic approaches could be directed separately towards GH deficiency or feeding disorders.
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Affiliation(s)
- Guillaume Osterstock
- Inserm U-661, Montpellier, France
- CNRS UMR 5203, Institut de Génomique Fonctionnelle, Montpellier, France
- Université Montpellier 1, 2, Montpellier, France
| | - Pauline Escobar
- Inserm U-661, Montpellier, France
- CNRS UMR 5203, Institut de Génomique Fonctionnelle, Montpellier, France
- Université Montpellier 1, 2, Montpellier, France
| | - Violeta Mitutsova
- Inserm U-661, Montpellier, France
- CNRS UMR 5203, Institut de Génomique Fonctionnelle, Montpellier, France
- Université Montpellier 1, 2, Montpellier, France
| | - Laurie-Anne Gouty-Colomer
- Inserm U-661, Montpellier, France
- CNRS UMR 5203, Institut de Génomique Fonctionnelle, Montpellier, France
- Université Montpellier 1, 2, Montpellier, France
| | - Pierre Fontanaud
- Inserm U-661, Montpellier, France
- CNRS UMR 5203, Institut de Génomique Fonctionnelle, Montpellier, France
- Université Montpellier 1, 2, Montpellier, France
| | - François Molino
- Inserm U-661, Montpellier, France
- CNRS UMR 5203, Institut de Génomique Fonctionnelle, Montpellier, France
- Université Montpellier 1, 2, Montpellier, France
| | - Jean-Alain Fehrentz
- Université Montpellier 1, 2, Montpellier, France
- CNRS UMR 5247, Institut des Biomolécules Max Mousseron, Montpellier, France
| | - Danielle Carmignac
- Division of Molecular Neuroendocrinology, MRC National Institute for Medical Research, The Ridgeway, Mill Hill, London, United Kingdom
| | - Jean Martinez
- Université Montpellier 1, 2, Montpellier, France
- CNRS UMR 5247, Institut des Biomolécules Max Mousseron, Montpellier, France
| | - Nathalie C. Guerineau
- Inserm U-661, Montpellier, France
- CNRS UMR 5203, Institut de Génomique Fonctionnelle, Montpellier, France
- Université Montpellier 1, 2, Montpellier, France
| | - Iain C. A. F. Robinson
- Division of Molecular Neuroendocrinology, MRC National Institute for Medical Research, The Ridgeway, Mill Hill, London, United Kingdom
| | - Patrice Mollard
- Inserm U-661, Montpellier, France
- CNRS UMR 5203, Institut de Génomique Fonctionnelle, Montpellier, France
- Université Montpellier 1, 2, Montpellier, France
| | - Pierre-François Méry
- Inserm U-661, Montpellier, France
- CNRS UMR 5203, Institut de Génomique Fonctionnelle, Montpellier, France
- Université Montpellier 1, 2, Montpellier, France
- * E-mail:
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17
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Veldhuis JD, Keenan DM. Secretagogues govern GH secretory-burst waveform and mass in healthy eugonadal and short-term hypogonadal men. Eur J Endocrinol 2008; 159:547-54. [PMID: 18703567 PMCID: PMC2680123 DOI: 10.1530/eje-08-0414] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
BACKGROUND GH pulses are putatively initiated by hypothalamic GH-releasing hormone (GHRH), amplified by GH-releasing peptide (GHRP), and inhibited by somatostatin (SS). OBJECTIVE To ascertain how secretagogues control the waveform (time evolution of release rates) as well as the mass of secretory bursts. DESIGN We quantified the shape of GH secretory bursts evoked by continuous combined i.v. infusion of maximally effective doses of GHRH and GHRP-2, and by bolus injection of each peptide after delivering L-arginine to restrain hypothalamic SS release in 12 healthy young men. METHODS A mathematically verified and experimentally validated variable-waveform deconvolution model was applied to intensively sampled GH time series. RESULTS The secretory-burst mode (time from burst onset to maximal secretion) was 19+/-0.69 min during saline infusion, and fell to a) 10.4+/-3.0 min during constant dual stimulation with GHRH/GHRP-2 (P<0.01), b) 14.6+/-1.8 min after l-arginine/GHRH (P<0.025), and c) 15.0+/-1.0 min after l-arginine/GHRH (P<0.01). Secretagogues augmented the mass of GH secreted in pulses by 44-, 42-, and 16-fold respectively, over saline (2.2+/-0.81 microg/l per h; P<0.001 for each). Pulse number and variability were unaffected. Applying the same methodology to ten other young men with acute leuprolide-induced hypogonadism yielded comparable waveform and mass estimates. CONCLUSION The present analyses in men demonstrate that peptidyl secretagogues modulate not only the magnitude but also the time course of the GH-release process in vivo independently of the short-term sex-steroid milieu.
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Affiliation(s)
- Johannes D Veldhuis
- Endocrine Research Unit, Mayo Medical and Graduate Schools, Mayo Clinic, Rochester, Minnesota 55905, USA.
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18
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Paulsen SJ, Larsen LK, Jelsing J, Janssen U, Gerstmayer B, Vrang N. Gene expression profiling of individual hypothalamic nuclei from single animals using laser capture microdissection and microarrays. J Neurosci Methods 2008; 177:87-93. [PMID: 18955080 DOI: 10.1016/j.jneumeth.2008.09.024] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2008] [Revised: 09/18/2008] [Accepted: 09/26/2008] [Indexed: 11/15/2022]
Abstract
In order to identify novel genes involved in appetite and body weight regulation we have developed a microarray based method suitable for detecting small changes in gene expression in discrete groups of hypothalamic neurons. The method is based on a combination of stereological sampling, laser capture microdissection (LCM), PCR based amplification (SuperAmp), and one-color cDNA microarray analysis. To validate the method we assessed and compared fasting induced changes in mRNA levels of Neuropeptide Y (NPY) and proopiomelanocortin (POMC) in the hypothalamic arcuate nucleus (ARC) of diet-induced obese rats using cDNA microarrays, quantitative PCR and in situ hybridization. All methods revealed statistically significant fasting-induced changes in NPY and POMC expression. An additional 3480 differentially expressed probes (fold change >1.22, t-test p=0.05) were identified in the microarray analysis. Our findings demonstrate a consistent gene expression pattern across three different gene expression detection methods and strongly suggest that LCM coupled microarray analysis combined with SuperAmp can be used as a semi-quantitative mRNA profiling tool. Importantly, the sensitivity of the method greatly improves the usefulness of the microarray technology for gene expression profiling in non-homogeneous tissues such as the brain.
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Affiliation(s)
- Sarah Juel Paulsen
- Rheoscience A/S, Glerupvej 1, DK-2610 Rødovre, Denmark; University of Southern Denmark, BMB, Campusvej 55, DK-5230 Odense M, Denmark.
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19
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Lee NJ, Enriquez RF, Boey D, Lin S, Slack K, Baldock PA, Herzog H, Sainsbury A. Synergistic attenuation of obesity by Y2- and Y4-receptor double knockout in ob/ob mice. Nutrition 2008; 24:892-9. [PMID: 18662863 DOI: 10.1016/j.nut.2008.06.019] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2008] [Accepted: 06/19/2008] [Indexed: 11/17/2022]
Abstract
OBJECTIVE Neuropeptide Y regulates numerous processes including food intake, body composition, and reproduction by at least five different Y receptors. We previously demonstrated a synergistic interaction between Y2 and Y4 receptors in reducing adiposity in chow- or fat-fed Y2Y4-receptor double-knockout mice. In the present study, we investigated whether this synergy could reduce the massive obesity of leptin-deficient ob/ob mice. METHODS Mice with germline deletions of Y2 and Y4 receptors were crossed onto the ob/ob strain. Body weight was measured weekly until 15-18 wk of age before decapitation for collection of trunk blood and tissues. RESULTS Male and female Y24ob triple mutants showed highly significant reductions in body weight and white adipose tissue mass compared with ob/ob mice. This reduction in body weight was not evident in Y2ob or Y4ob double mutants, and the effect on adiposity was significantly greater than that seen in Y2ob or Y4ob mice. These changes were associated with significant attenuation of the increased brown adipose tissue mass and small intestinal hypertrophy seen in ob/ob mice and with normalization of the low circulating free thyroxine concentrations seen in female ob/ob mice and the high circulating corticosterone concentrations seen in male ob/ob mice. CONCLUSION These data reveal a synergistic interaction between Y2 and Y4 receptors in attenuating the massive obesity of ob/ob mice, possibly mediated by stimulation of thyroid function and inhibition of intestinal nutrient absorption. Dual pharmacologic antagonism of Y2 and Y4 receptors could help people to attain and maintain a healthy weight.
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Affiliation(s)
- Nicola J Lee
- Neuroscience Research Program, Garvan Institute of Medical Research, St. Vincent's Hospital, Sydney, New South Wales, Australia
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Chiou TJ, Chu ST, Tzeng WF, Huang YC, Liao CJ. Arsenic trioxide impairs spermatogenesis via reducing gene expression levels in testosterone synthesis pathway. Chem Res Toxicol 2008; 21:1562-9. [PMID: 18630931 DOI: 10.1021/tx700366x] [Citation(s) in RCA: 67] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Arsenic trioxide (As2O3) has recently received a great deal of attention because of its capacity to cause complete remission of acute promyelocytic leukemia (APL). To evaluate possible toxicity on the male reproductive system during arsenic therapy, male mice were used as a model. Outbred mice (ICR/CD1 and S-W, 6 weeks old) were subcutaneously administered As2O3 continuously for 5 days, with a 2-day interval, for a period of 3 weeks. As2O3 doses were 0, 0.15, 0.3, 1.5, and 3.0 mg/kg of body weight, respectively. No mice died in any dosage group. Our data showed no significant changes in food consumption or in the weight of the body, liver, testis, or epididymis after As2O3 treatment. Using histological observation to identify the stages of seminiferous tubules, we showed that As2O3 treatment resulted in the inhibition of spermatogenesis. The frequency of mature seminiferous tubules (stages VII and VIII) was markedly decreased after As2O3 treatment. A significant decrease in sperm motility and viability also was found with computer-assisted sperm analysis (CASA) and a SYBR14/PI staining assay. Using an enzyme-linked immunosorbent assay (ELISA), we found a significant decrease in levels of plasma luteinizing hormone (LH) at a dose of 3.0 mg/kg body weight. No significant difference was found in plasma follicle-stimulating hormone (FSH) in all dosages. A significant decrease was found in plasma testosterone in all dosages, but no difference in intratesticular testosterone, with the exception of As2O3 at a dose of 3.0 mg/kg body weight. Moreover, there was a significant decrease in the levels of mRNA involved in testicular testosterone synthesis, cytochrome P450 side chain cleavage (P450scc), 3beta-hydroxysteroid dehydrogenase (3beta-HSD), and cytochrome P450 17-alpha hydroxylase/C17-20 lyase (Cyp17). The use of immunohistological observation showed no obvious difference in the testosterone level of Leydig cells of mice treated with As2O3 at doses of 0.3 and 1.5 mg/kg body weight. We concluded that As2O3 treatment caused damage to sperm mobility and viability. As2O3 treatment disturbed spermatogenesis via reducing gene expression of the key enzymes in testosterone synthesis.
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Affiliation(s)
- Tzeon-Jye Chiou
- Division of Transfusion Medicine, Department of Medicine, Taipei Veterans General Hospital, National Yang-Ming University School of Medicine, Taipei, Taiwan.
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Martin B, Golden E, Carlson OD, Egan JM, Mattson MP, Maudsley S. Caloric restriction: impact upon pituitary function and reproduction. Ageing Res Rev 2008; 7:209-24. [PMID: 18329344 DOI: 10.1016/j.arr.2008.01.002] [Citation(s) in RCA: 64] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2007] [Revised: 01/25/2008] [Accepted: 01/28/2008] [Indexed: 01/05/2023]
Abstract
Reduced energy intake, or caloric restriction (CR), is known to extend life span and to retard age-related health decline in a number of different species, including worms, flies, fish, mice and rats. CR has been shown to reduce oxidative stress, improve insulin sensitivity, and alter neuroendocrine responses and central nervous system (CNS) function in animals. CR has particularly profound and complex actions upon reproductive health. At the reductionist level the most crucial physiological function of any organism is its capacity to reproduce. For a successful species to thrive, the balance between available energy (food) and the energy expenditure required for reproduction must be tightly linked. An ability to coordinate energy balance and fecundity involves complex interactions of hormones from both the periphery and the CNS and primarily centers upon the master endocrine gland, the anterior pituitary. In this review article we review the effects of CR on pituitary gonadotrope function and on the male and female reproductive axes. A better understanding of how dietary energy intake affects reproductive axis function and endocrine pulsatility could provide novel strategies for the prevention and management of reproductive dysfunction and its associated comorbidities.
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Affiliation(s)
- Bronwen Martin
- Laboratory of Neurosciences, National Institute on Aging Intramural Research Program, 5600 Nathan Shock Drive, Baltimore, MD 21224, USA.
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