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Wang B, Cui A, Xu Y, Zhang Y, Jiang Y, Liu X. Food deprivation differentially modulates gene expression of LPXRFa and kisspeptin systems in the brain-pituitary axis of half-smooth tongue sole ( Cynoglossus semilaevis). Front Endocrinol (Lausanne) 2023; 14:1099832. [PMID: 37033260 PMCID: PMC10081681 DOI: 10.3389/fendo.2023.1099832] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/16/2022] [Accepted: 03/15/2023] [Indexed: 04/11/2023] Open
Abstract
LPXRFa, also known as gonadotropin-inhibitory hormone (GnIH), and kisspeptin (Kiss) are two major hypothalamic peptides that modulate the reproductive axis of vertebrates, including teleosts. However, little information is available regarding the actions of nutritional status on the regulation of these two neuroendocrine systems in fish. Herein, we assessed the effects of starvation and refeeding on the expression of lpxrfa, kiss2 and their receptors (lpxrfa-r and kiss2r respectively) at the brain-pituitary level of half-smooth tongue sole (Cynoglossus semilaevis). Food deprivation for 4 weeks induced a rise in brain lpxrfa as well as brain and pituitary lpxrfa-r mRNA levels, and refeeding restored brain lpxrfa and lpxrfa-r expression back to normal. However, pituitary lpxrfa-r mRNA levels still remained high after 1 week of refeeding. Neither lpxrfa nor kiss2 transcripts in the pituitary were altered by fasting, but their mRNA levels increased significantly after 1 week of refeeding, and declined back to the control levels after 2 weeks of refeeding. None of brain kiss2 and kiss2r along with pituitary kiss2r transcripts were modified by the nutritional status. In summary, our results revealed an interaction between energy status and the elements of LPXRFa and Kiss systems in the brain-pituitary axis of half-smooth tongue sole. Food deprivation and refeeding differentially regulated the two systems, which provided additional evidence for the involvement of the LPXRFa and Kiss systems in the regulation of reproduction by energy balance in non-mammalian species.
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Affiliation(s)
- Bin Wang
- Key Laboratory of Sustainable Development of Marine Fisheries, Ministry of Agriculture and Rural Affairs, Yellow Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, Qingdao, China
- Joint Laboratory for Deep Blue Fishery Engineering, Pilot National Laboratory for Marine Science and Technology (Qingdao), Qingdao, China
| | - Aijun Cui
- Key Laboratory of Sustainable Development of Marine Fisheries, Ministry of Agriculture and Rural Affairs, Yellow Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, Qingdao, China
- Joint Laboratory for Deep Blue Fishery Engineering, Pilot National Laboratory for Marine Science and Technology (Qingdao), Qingdao, China
| | - Yongjiang Xu
- Key Laboratory of Sustainable Development of Marine Fisheries, Ministry of Agriculture and Rural Affairs, Yellow Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, Qingdao, China
- Joint Laboratory for Deep Blue Fishery Engineering, Pilot National Laboratory for Marine Science and Technology (Qingdao), Qingdao, China
- *Correspondence: Yongjiang Xu,
| | - Yaxing Zhang
- Key Laboratory of Sustainable Development of Marine Fisheries, Ministry of Agriculture and Rural Affairs, Yellow Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, Qingdao, China
| | - Yan Jiang
- Key Laboratory of Sustainable Development of Marine Fisheries, Ministry of Agriculture and Rural Affairs, Yellow Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, Qingdao, China
- Joint Laboratory for Deep Blue Fishery Engineering, Pilot National Laboratory for Marine Science and Technology (Qingdao), Qingdao, China
| | - Xuezhou Liu
- Key Laboratory of Sustainable Development of Marine Fisheries, Ministry of Agriculture and Rural Affairs, Yellow Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, Qingdao, China
- Joint Laboratory for Deep Blue Fishery Engineering, Pilot National Laboratory for Marine Science and Technology (Qingdao), Qingdao, China
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Campo A, Dufour S, Rousseau K. Tachykinins, new players in the control of reproduction and food intake: A comparative review in mammals and teleosts. Front Endocrinol (Lausanne) 2022; 13:1056939. [PMID: 36589829 PMCID: PMC9800884 DOI: 10.3389/fendo.2022.1056939] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/29/2022] [Accepted: 11/07/2022] [Indexed: 12/23/2022] Open
Abstract
In vertebrates, the tachykinin system includes tachykinin genes, which encode one or two peptides each, and tachykinin receptors. The complexity of this system is reinforced by the massive conservation of gene duplicates after the whole-genome duplication events that occurred in vertebrates and furthermore in teleosts. Added to this, the expression of the tachykinin system is more widespread than first thought, being found beyond the brain and gut. The discovery of the co-expression of neurokinin B, encoded by the tachykinin 3 gene, and kisspeptin/dynorphin in neurons involved in the generation of GnRH pulse, in mammals, put a spotlight on the tachykinin system in vertebrate reproductive physiology. As food intake and reproduction are linked processes, and considering that hypothalamic hormones classically involved in the control of reproduction are reported to regulate also appetite and energy homeostasis, it is of interest to look at the potential involvement of tachykinins in these two major physiological functions. The purpose of this review is thus to provide first a general overview of the tachykinin system in mammals and teleosts, before giving a state of the art on the different levels of action of tachykinins in the control of reproduction and food intake. This work has been conducted with a comparative point of view, highlighting the major similarities and differences of tachykinin systems and actions between mammals and teleosts.
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Affiliation(s)
- Aurora Campo
- Muséum National d’Histoire Naturelle, Research Unit Unité Mixte de Recherche Biologie des Organsimes et Ecosystèmes Aquatiques (UMR BOREA), Biology of Aquatic Organisms and Ecosystems, Centre National pour la Recherche Scientifique (CNRS), Institut de Recherche pour le Développemen (IRD), Sorbonne Université, Paris, France
- Volcani Institute, Agricultural Research Organization, Rishon LeTsion, Israel
| | - Sylvie Dufour
- Muséum National d’Histoire Naturelle, Research Unit Unité Mixte de Recherche Biologie des Organsimes et Ecosystèmes Aquatiques (UMR BOREA), Biology of Aquatic Organisms and Ecosystems, Centre National pour la Recherche Scientifique (CNRS), Institut de Recherche pour le Développemen (IRD), Sorbonne Université, Paris, France
| | - Karine Rousseau
- Muséum National d’Histoire Naturelle, Research Unit Unité Mixte de Recherche Biologie des Organsimes et Ecosystèmes Aquatiques (UMR BOREA), Biology of Aquatic Organisms and Ecosystems, Centre National pour la Recherche Scientifique (CNRS), Institut de Recherche pour le Développemen (IRD), Sorbonne Université, Paris, France
- Muséum National d’Histoire Naturelle, Research Unit PhyMA Physiologie Moléculaire et Adaptation CNRS, Paris, France
- *Correspondence: Karine Rousseau,
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Odle AK, Akhter N, Syed MM, Allensworth-James ML, Beneš H, Melgar Castillo AI, MacNicol MC, MacNicol AM, Childs GV. Leptin Regulation of Gonadotrope Gonadotropin-Releasing Hormone Receptors As a Metabolic Checkpoint and Gateway to Reproductive Competence. Front Endocrinol (Lausanne) 2018; 8:367. [PMID: 29354094 PMCID: PMC5760501 DOI: 10.3389/fendo.2017.00367] [Citation(s) in RCA: 39] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/28/2017] [Accepted: 12/13/2017] [Indexed: 12/20/2022] Open
Abstract
The adipokine leptin signals the body's nutritional status to the brain, and particularly, the hypothalamus. However, leptin receptors (LEPRs) can be found all throughout the body and brain, including the pituitary. It is known that leptin is permissive for reproduction, and mice that cannot produce leptin (Lep/Lep) are infertile. Many studies have pinpointed leptin's regulation of reproduction to the hypothalamus. However, LEPRs exist at all levels of the hypothalamic-pituitary-gonadal axis. We have previously shown that deleting the signaling portion of the LEPR specifically in gonadotropes impairs fertility in female mice. Our recent studies have targeted this regulation to the control of gonadotropin releasing hormone receptor (GnRHR) expression. The hypotheses presented here are twofold: (1) cyclic regulation of pituitary GnRHR levels sets up a target metabolic checkpoint for control of the reproductive axis and (2) multiple checkpoints are required for the metabolic signaling that regulates the reproductive axis. Here, we emphasize and explore the relationship between the hypothalamus and the pituitary with regard to the regulation of GnRHR. The original data we present strengthen these hypotheses and build on our previous studies. We show that we can cause infertility in 70% of female mice by deleting all isoforms of LEPR specifically in gonadotropes. Our findings implicate activin subunit (InhBa) mRNA as a potential leptin target in gonadotropes. We further show gonadotrope-specific upregulation of GnRHR protein (but not mRNA levels) following leptin stimulation. In order to try and understand this post-transcriptional regulation, we tested candidate miRNAs (identified with in silico analysis) that may be binding the Gnrhr mRNA. We show significant upregulation of one of these miRNAs in our gonadotrope-Lepr-null females. The evidence provided here, combined with our previous work, lay the foundation for metabolically regulated post-transcriptional control of the gonadotrope. We discuss possible mechanisms, including miRNA regulation and the involvement of the RNA binding protein, Musashi. We also demonstrate how this regulation may be vital for the dynamic remodeling of gonadotropes in the cycling female. Finally, we propose that the leptin receptivity of both the hypothalamus and the pituitary are vital for the body's ability to delay or slow reproduction during periods of low nutrition.
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Affiliation(s)
- Angela K. Odle
- Department of Neurobiology and Developmental Sciences, University of Arkansas for Medical Sciences, Little Rock, AR, United States
| | - Noor Akhter
- Department of Neurobiology and Developmental Sciences, University of Arkansas for Medical Sciences, Little Rock, AR, United States
| | - Mohsin M. Syed
- Department of Neurobiology and Developmental Sciences, University of Arkansas for Medical Sciences, Little Rock, AR, United States
| | - Melody L. Allensworth-James
- Department of Neurobiology and Developmental Sciences, University of Arkansas for Medical Sciences, Little Rock, AR, United States
| | - Helen Beneš
- Department of Neurobiology and Developmental Sciences, University of Arkansas for Medical Sciences, Little Rock, AR, United States
| | - Andrea I. Melgar Castillo
- Department of Neurobiology and Developmental Sciences, University of Arkansas for Medical Sciences, Little Rock, AR, United States
| | - Melanie C. MacNicol
- Department of Neurobiology and Developmental Sciences, University of Arkansas for Medical Sciences, Little Rock, AR, United States
| | - Angus M. MacNicol
- Department of Neurobiology and Developmental Sciences, University of Arkansas for Medical Sciences, Little Rock, AR, United States
| | - Gwen V. Childs
- Department of Neurobiology and Developmental Sciences, University of Arkansas for Medical Sciences, Little Rock, AR, United States
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Varlamov O. Western-style diet, sex steroids and metabolism. Biochim Biophys Acta Mol Basis Dis 2016; 1863:1147-1155. [PMID: 27264336 DOI: 10.1016/j.bbadis.2016.05.025] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2016] [Revised: 05/27/2016] [Accepted: 05/28/2016] [Indexed: 12/14/2022]
Abstract
The evolutionary transition from hunting to farming was associated with introduction of carbohydrate-rich diets. Today, the increased consumption of simple sugars and high-fat food brought about by Western-style diet and physical inactivity are leading causes of the growing obesity epidemic in the Western society. The extension of human lifespan far beyond reproductive age increased the burden of metabolic disorders associated with overnutrition and age-related hypogonadism. Sex steroids are essential regulators of both reproductive function and energy metabolism, whereas their imbalance causes infertility, obesity, glucose intolerance, dyslipidemia, and increased appetite. Clinical and translational studies suggest that dietary restriction and weight control can improve metabolic and reproductive outcomes of sex hormone-related pathologies, including testosterone deficiency in men and natural menopause and hyperandrogenemia in women. Minimizing metabolic and reproductive decline through rationally designed diet and exercise can help extend human reproductive age and promote healthy aging. This article is part of a Special Issue entitled: Oxidative Stress and Mitochondrial Quality in Diabetes/Obesity and Critical Illness Spectrum of Diseases - edited by P. Hemachandra Reddy.
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Affiliation(s)
- Oleg Varlamov
- Division of Diabetes, Obesity, and Metabolism, Oregon National Primate Research Center, Beaverton, OR 97006, United States.
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Clarke IJ. Interface between metabolic balance and reproduction in ruminants: focus on the hypothalamus and pituitary. Horm Behav 2014; 66:15-40. [PMID: 24568750 DOI: 10.1016/j.yhbeh.2014.02.005] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/02/2013] [Revised: 02/13/2014] [Accepted: 02/15/2014] [Indexed: 01/24/2023]
Abstract
This article is part of a Special Issue "Energy Balance". The interface between metabolic regulators and the reproductive system is reviewed with special reference to the sheep. Even though sheep are ruminants with particular metabolic characteristics, there is a broad consensus across species in the way that the reproductive system is influenced by metabolic state. An update on the neuroendocrinology of reproduction indicates the need to account for the way that kisspeptin provides major drive to gonadotropin releasing hormone (GnRH) neurons and also mediates the feedback effects of gonadal steroids. The way that kisspeptin function is influenced by appetite regulating peptides (ARP) is considered. Another newly recognised factor is gonadotropin inhibitory hormone (GnIH), which has a dual function in that it suppresses reproductive function whilst also acting as an orexigen. Our understanding of the regulation of food intake and energy expenditure has expanded exponentially in the last 3 decades and historical perspective is provided. The function of the regulatory factors and the hypothalamic cellular systems involved is reviewed with special reference to the sheep. Less is known of these systems in the cow, especially the dairy cow, in which a major fertility issue has emerged in parallel with selection for increased milk production. Other endocrine systems--the hypothalamo-pituitary-adrenal axis, the growth hormone (GH) axis and the thyroid hormones--are influenced by metabolic state and are relevant to the interface between metabolic function and reproduction. Special consideration is given to issues such as season and lactation, where the relationship between metabolic hormones and reproductive function is altered.
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Affiliation(s)
- Iain J Clarke
- Monash University, Department of Physiology, Wellington Road, Clayton 3168, Australia.
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Sliwowska JH, Fergani C, Gawałek M, Skowronska B, Fichna P, Lehman MN. Insulin: its role in the central control of reproduction. Physiol Behav 2014; 133:197-206. [PMID: 24874777 DOI: 10.1016/j.physbeh.2014.05.021] [Citation(s) in RCA: 62] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2013] [Revised: 05/13/2014] [Accepted: 05/19/2014] [Indexed: 12/11/2022]
Abstract
Insulin has long been recognized as a key regulator of energy homeostasis via its actions at the level of the brain, but in addition, plays a role in regulating neural control of reproduction. In this review, we consider and compare evidence from animal models demonstrating a role for insulin for physiological control of reproduction by effects on GnRH/LH secretion. We also review the role that insulin plays in prenatal programming of adult reproduction, and consider specific candidate neurons in the adult hypothalamus by which insulin may act to regulate reproductive function. Finally, we review clinical evidence of the role that insulin may play in adult human fertility and reproductive disorders. Overall, while insulin appears to have a significant impact on reproductive neuroendocrine function, there are many unanswered questions regarding its precise sites and mechanisms of action, and their impact on developing and adult reproductive neuroendocrine function.
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Affiliation(s)
- Joanna H Sliwowska
- Laboratory of Neurobiology, Institute of Zoology, Poznan University of Life Sciences, ul. Wojska Polskiego 71 C, 60-625 Poznan, Poland.
| | - Chrysanthi Fergani
- Department of Neurobiology and Anatomical Sciences, University of Mississippi Medical Center, Jackson, MS 39232, USA.
| | - Monika Gawałek
- Laboratory of Neurobiology, Institute of Zoology, Poznan University of Life Sciences, ul. Wojska Polskiego 71 C, 60-625 Poznan, Poland.
| | - Bogda Skowronska
- Department of Pediatric Diabetes and Obesity, Poznan University of Medical Sciences, Szpitalna Str. 27/33, 60-572 Poznan, Poland.
| | - Piotr Fichna
- Department of Pediatric Diabetes and Obesity, Poznan University of Medical Sciences, Szpitalna Str. 27/33, 60-572 Poznan, Poland.
| | - Michael N Lehman
- Department of Neurobiology and Anatomical Sciences, University of Mississippi Medical Center, Jackson, MS 39232, USA.
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Verma S, Kirigiti M, Millar RP, Grove KL, Smith MS. Endogenous kisspeptin tone is a critical excitatory component of spontaneous GnRH activity and the GnRH response to NPY and CART. Neuroendocrinology 2014; 99:190-203. [PMID: 25011649 PMCID: PMC4201869 DOI: 10.1159/000365419] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/18/2013] [Accepted: 06/22/2014] [Indexed: 12/17/2022]
Abstract
BACKGROUND/AIMS Kisspeptin is the major excitatory regulator of gonadotropin-releasing hormone (GnRH) neurons and is responsible for basal GnRH/LH release and the GnRH/LH surge. Although it is widely assumed, based on mutations in kisspeptin and Kiss1R, that kisspeptin acts to sustain basal GnRH neuronal activity, there have been no studies to investigate whether endogenous basal kisspeptin tone plays a direct role in basal spontaneous GnRH neuronal excitability. It is also of interest to examine possible interactions between endogenous kisspeptin tone and other neuropeptides that have direct effects on GnRH neurons, such as neuropeptide Y (NPY) or cocaine- and amphetamine-regulated transcript (CART), since the activity of all these neuropeptides changes during states of negative energy balance. METHODS Loose cell-attached and whole-cell current patch-clamp recordings were made from GnRH-GFP neurons in hypothalamic slices from female and male rats. RESULTS Kisspeptin activated GnRH neurons in a concentration-dependent manner with an EC50 of 3.32 ± 0.02 nM. Surprisingly, a kisspeptin antagonist, Peptide 347, suppressed spontaneous activity in GnRH neurons, demonstrating the essential nature of the endogenous kisspeptin tone. Furthermore, inhibition of endogenous kisspeptin tone blocked the direct activation of GnRH cells that occurs in response to antagonism of NPY Y5 receptor or by CART. CONCLUSIONS Our electrophysiology studies suggest that basal endogenous kisspeptin tone is not only essential for spontaneous GnRH neuronal firing, but it is also required for the net excitatory effects of other neuropeptides, such as CART or NPY antagonism, on GnRH neurons. Therefore, endogenous kisspeptin tone could serve as the linchpin in GnRH activation or inhibition.
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Affiliation(s)
- Saurabh Verma
- Division of Diabetes, Obesity and Metabolism, Oregon National Primate Research Center, Oregon Health & Science University, Beaverton, Oregon 97006
| | - Melissa Kirigiti
- Division of Diabetes, Obesity and Metabolism, Oregon National Primate Research Center, Oregon Health & Science University, Beaverton, Oregon 97006
| | - Robert P. Millar
- MRC Receptor Biology & Reproductive Health, University of Pretoria, Pretoria, South Africa
| | - Kevin L. Grove
- Division of Diabetes, Obesity and Metabolism, Oregon National Primate Research Center, Oregon Health & Science University, Beaverton, Oregon 97006
| | - M. Susan Smith
- Division of Diabetes, Obesity and Metabolism, Oregon National Primate Research Center, Oregon Health & Science University, Beaverton, Oregon 97006
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Hill JW, Alreja M, Elias CF. From precocious puberty to infertility: metabolic control of the reproductive function. Front Endocrinol (Lausanne) 2013; 4:43. [PMID: 23565110 PMCID: PMC3613725 DOI: 10.3389/fendo.2013.00043] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/06/2013] [Accepted: 03/16/2013] [Indexed: 12/18/2022] Open
Affiliation(s)
- Jennifer W. Hill
- Department of Physiology and Pharmacology, University of ToledoToledo, OH, USA
- Department of Obstetrics and Gynecology, University of ToledoToledo, OH, USA
| | | | - Carol F. Elias
- Department of Molecular and Integrative Physiology, University of MichiganAnn Arbor, MI, USA
- *Correspondence:
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Carlton ED, Demas GE, French SS. Leptin, a neuroendocrine mediator of immune responses, inflammation, and sickness behaviors. Horm Behav 2012; 62:272-9. [PMID: 22561456 DOI: 10.1016/j.yhbeh.2012.04.010] [Citation(s) in RCA: 65] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/28/2011] [Revised: 04/05/2012] [Accepted: 04/18/2012] [Indexed: 01/27/2023]
Abstract
Effective immune responses are coordinated by interactions among the nervous, endocrine, and immune systems. Mounting immune, inflammatory, and sickness responses requires substantial energetic investments, and as such, an organism may need to balance energy allocation to these processes with the energetic demands of other competing physiological systems. The metabolic hormone leptin appears to be mediating trade-offs between the immune system and other physiological systems through its actions on immune cells and the brain. Here we review the evidence in both mammalian and non-mammalian vertebrates that suggests leptin is involved in regulating immune responses, inflammation, and sickness behaviors. Leptin has also been implicated in the regulation of seasonal immune responses, including sickness; however, the precise physiological mechanisms remain unclear. Thus, we discuss recent data in support of leptin as a mediator of seasonal sickness responses and provide a theoretical model that outlines how seasonal cues, leptin, and proinflammatory cytokines may interact to coordinate seasonal immune and sickness responses.
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Affiliation(s)
- Elizabeth D Carlton
- Department of Biology, Program in Neuroscience and Center for the Integrative Study of Animal Behavior, Indiana University, Bloomington, IN 47405, USA.
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10
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Stevenson TJ, Hahn TP, MacDougall-Shackleton SA, Ball GF. Gonadotropin-releasing hormone plasticity: a comparative perspective. Front Neuroendocrinol 2012; 33:287-300. [PMID: 23041619 PMCID: PMC3484179 DOI: 10.1016/j.yfrne.2012.09.001] [Citation(s) in RCA: 59] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/15/2012] [Revised: 09/04/2012] [Accepted: 09/05/2012] [Indexed: 11/16/2022]
Abstract
Gonadotropin-releasing hormone 1 (GnRH1) is a key regulator of the reproductive neuroendocrine system in vertebrates. Recent developments have suggested that GnRH1 neurons exhibit far greater plasticity at the cellular and molecular levels than previously thought. Furthermore, there is growing evidence that sub-populations of GnRH1 neurons in the preoptic area are highly responsive to specific environmental and hormonal conditions. In this paper we discuss findings that reveal large variation in GnRH1 mRNA and protein expression that are regulated by social cues, photoperiod, and hormonal feedback. We draw upon studies using histochemistry and immediate early genes (e.g., c-FOS/ZENK) to illustrate that specific groups of GnRH1 neurons are topographically organized. Based on data from diverse vertebrate species, we suggest that GnRH1 expression within individuals is temporally dynamic and this plasticity may be evolutionarily conserved. We suggest that the plasticity observed in other neuropeptide systems (i.e. kisspeptin) may have evolved in a similar manner.
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Affiliation(s)
- T J Stevenson
- Institute for Mind and Biology, University of Chicago, Chicago, IL 60637, USA.
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11
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Kumari D, Nair N, Bedwal RS. Protein carbonyl, 3β-, and 17β-hydroxysteroid dehydrogenases in testes and serum FSH, LH, and testosterone levels in zinc deficient Wistar rats. Biofactors 2012; 38:234-9. [PMID: 22505238 DOI: 10.1002/biof.1020] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/02/2011] [Accepted: 03/08/2012] [Indexed: 12/14/2022]
Abstract
The present study evaluated protein oxidation, alteration in hydroxysteroid dehydrogenases (3β- and 17β HSD) in testes and serum hormonal profiles of dietary zinc deficient Wistar rats. Pre-pubertal rats were divided into three groups: zinc control (ZC), pairfed (PF), and zinc deficient (ZD) and fed 100 ppm (ZC and PF groups) and 1.0 ppm (ZD group) zinc diet for 2- and 4-weeks. The testes from zinc deficient groups exhibited significant increase in total protein (2 weeks) and protein carbonyl (2- and 4-weeks) concentration as well as 3β- and 17β-hydroxysteroid dehydrogenase activities (4 weeks), whereas a significant decrease was recorded in total protein (testes 4 weeks; serum 2- and 4-weeks), total zinc (testes and serum 2- and 4-weeks), 3β- and 17β-hydroxysteroid dehydrogenase activities (testes 2 weeks), and serum hormonal profiles (FSH and testosterone 2- and 4-weeks). However, LH was below the detectable limits. These results reflect that zinc deficiency during pre-pubertal period affected total protein and zinc status, elevates protein oxidation, and causes dysregulation of the hydroxysteroid dehydrogenases. Low level of zinc attenuated the gonadal physiology which indicates that the metabolic regulation of testes is mediated by combined effects of a specific response (caused by decreased zinc concentration) and a nonspecific response (inhibition of gonadotrophin secretion). All these contribute to testicular dysfunction.
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Affiliation(s)
- Deepa Kumari
- Cell Biology Laboratory, Department of Zoology, University of Rajasthan, Jaipur, India.
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