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Zhao S, Guo Z, Xiang W, Wang P. The neuroendocrine pathways and mechanisms for the control of the reproduction in female pigs. Anim Reprod 2021; 18:e20210063. [PMID: 34925558 PMCID: PMC8677349 DOI: 10.1590/1984-3143-ar2021-0063] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2021] [Accepted: 11/10/2021] [Indexed: 01/05/2024] Open
Abstract
Within the hypothalamic-pituitary-gonad (HPG) axis, the major hierarchical component is gonadotropin-releasing hormone (GnRH) neurons, which directly or indirectly receive regulatory inputs from a wide array of regulatory signals and pathways, involving numerous circulating hormones, neuropeptides, and neurotransmitters, and which operate as a final output for the brain control of reproduction. In recent years, there has been an increasing interest in neuropeptides that have the potential to stimulate or inhibit GnRH in the hypothalamus of pigs. Among them, Kisspeptin is a key component in the precise regulation of GnRH neuron secretion activity. Besides, other neuropeptides, including neurokinin B (NKB), neuromedin B (NMB), neuromedin S (NMS), α-melanocyte-stimulating hormone (α-MSH), Phoenixin (PNX), show potential for having a stimulating effect on GnRH neurons. On the contrary, RFamide-related peptide-3 (RFRP-3), endogenous opioid peptides (EOP), neuropeptide Y (NPY), and Galanin (GAL) may play an inhibitory role in the regulation of porcine reproductive nerves and may directly or indirectly regulate GnRH neurons. By combining data from suitable model species and pigs, we aim to provide a comprehensive summary of our current understanding of the neuropeptides acting on GnRH neurons, with a particular focus on their central regulatory pathways and underlying molecular basis.
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Affiliation(s)
- Shuang Zhao
- College of Bioengineering, Chongqing University, Chongqing, P. R. China
| | - Zongyi Guo
- Chongqing Academy of Animal Sciences, Chongqing, P. R. China
| | - Wei Xiang
- School of Advanced Agriculture and Bioengineering, Yangtze Normal University, Fuling of Chongqing, P. R. China
| | - Pingqing Wang
- College of Bioengineering, Chongqing University, Chongqing, P. R. China
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Altinkaya SO. Galanin and glypican-4 levels depending on metabolic and cardiovascular risk factors in patients with polycystic ovary syndrome. ARCHIVES OF ENDOCRINOLOGY AND METABOLISM 2021; 65:479-487. [PMID: 33740336 PMCID: PMC10522184 DOI: 10.20945/2359-3997000000340] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/09/2020] [Accepted: 01/04/2021] [Indexed: 11/23/2022]
Abstract
OBJECTIVE Galanin is a neuropeptide which has effects not only on metabolic syndrome but also on reproduction. Glypican-4 is an adipokine associated with insulin sensitivity by interacting directly with the insulin receptor. This study evaluated serum concentrations of galanin and glypican-4 in relation with the hormonal profile as well as metabolic and cardiovascular risk factors in patients with and without polycystic ovary syndrome (PCOS). METHODS A total of 44 women with PCOS and 44 age-matched controls were eligible. Hirsutism scores, hormonal profile, metabolic and cardiovascular risk factors as well as galanin and glypican-4 levels were evaluated in each subject. RESULTS Women with PCOS exhibited lower levels of galanin (20.2 pg/mL versus 26.4 pg/mL, p = 0.002) and higher concentrations of glypican-4 (3.1 ng/mL versus 2.6 ng/mL, p < 0.001) than controls. Both adipokines were correlated positively with body mass index (BMI), insulin, triglyceride and Homeostasis Model Assessment (HOMA) index; glypican-4 also showed positive correlations with fasting blood glucose, free testosterone, modified Ferriman-Gallwey scores (p < 0.05). Multiple Linear Regression analyses showed that PCOS and BMI were the best predictors affecting galanin levels with a decreasing and increasing effect respectively; however BMI was the best predictor affecting glypican-4 levels with an increasing effect (p < 0.001). CONCLUSION Galanin levels were lower and glypican-4 levels were higher in women with PCOS than controls. Further studies are needed to determine whether these adipokines could be used as additional markers for insulin sensitivity and lipid profile and whether they might play a role in the pathogenesis of PCOS, in which metabolic cardiovascular risks are increased.
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Pinto P, Velez Z, Sousa C, Santos S, Andrade A, Alvarado MV, Felip A, Zanuy S, Canário AVM. Responsiveness of pituitary to galanin throughout the reproductive cycle of male European sea bass (Dicentrarchus labrax). Gen Comp Endocrinol 2017. [PMID: 28636888 DOI: 10.1016/j.ygcen.2017.06.009] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
The neuropeptide galanin (Gal) is a putative factor regulating puberty onset and reproduction through its actions on the pituitary. The present study investigated the pituitary responsiveness to galanin and the patterns of galanin receptors (Galrs) expression throughout the reproductive cycle of two years old male European sea bass (Dicentrarchus labrax), an important aquaculture species. Quantitative analysis of pituitary and hypothalamus transcript expression of four galr subtypes revealed differential regulation according to the testicular developmental stage, with an overall decrease in expression from the immature stage to the mid-recrudescence stage. Incubation of pituitary cells with mammalian 1-29Gal peptide induced significant changes in cAMP concentration, with sensitivities that varied according to the testicular development stages. Furthermore 1-29Gal was able to stimulate both follicle stimulating hormone (Fsh) and luteinizing hormone (Lh) release from pituitary cell suspensions. The magnitude of the effects and effective concentrations varied according to reproductive stage, with generalized induction of Fsh and Lh release in animals sampled in January (full spermiation). The differential expression of galrs in pituitary and hypothalamus across the reproductive season, together with the differential effects of Gal on gonadotropins release in vitro strongly suggests the involvement of the galaninergic system in the regulation the hypothalamus-pituitary-gonad axis of male sea bass. This is to our knowledge the first clear evidence for the involvement of galanin in the regulation of reproduction in non-mammalian vertebrates.
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Affiliation(s)
- P Pinto
- CCMAR-Centro de Ciências do Mar, University of Algarve, Campus de Gambelas, 8005-139 Faro, Portugal.
| | - Z Velez
- CCMAR-Centro de Ciências do Mar, University of Algarve, Campus de Gambelas, 8005-139 Faro, Portugal.
| | - C Sousa
- CCMAR-Centro de Ciências do Mar, University of Algarve, Campus de Gambelas, 8005-139 Faro, Portugal
| | - S Santos
- CCMAR-Centro de Ciências do Mar, University of Algarve, Campus de Gambelas, 8005-139 Faro, Portugal
| | - A Andrade
- CCMAR-Centro de Ciências do Mar, University of Algarve, Campus de Gambelas, 8005-139 Faro, Portugal
| | - M V Alvarado
- CSIC-Instituto de Acuicultura de Torre de la Sal, Ribera de Cabanes, 12595 Castellón, Spain
| | - A Felip
- CSIC-Instituto de Acuicultura de Torre de la Sal, Ribera de Cabanes, 12595 Castellón, Spain
| | - S Zanuy
- CSIC-Instituto de Acuicultura de Torre de la Sal, Ribera de Cabanes, 12595 Castellón, Spain
| | - A V M Canário
- CCMAR-Centro de Ciências do Mar, University of Algarve, Campus de Gambelas, 8005-139 Faro, Portugal
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Celik O, Aydin S, Celik N, Yilmaz M. Peptides: Basic determinants of reproductive functions. Peptides 2015; 72:34-43. [PMID: 26074346 DOI: 10.1016/j.peptides.2015.05.016] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/13/2015] [Revised: 05/28/2015] [Accepted: 05/29/2015] [Indexed: 12/22/2022]
Abstract
Mammalian reproduction is a costly process in terms of energy consumption. The critical information regarding metabolic status is signaled to the hypothalamus mainly through peripheral peptides from the adipose tissue and gastrointestinal tract. Changes in energy stores produce fluctuations in leptin, insulin, ghrelin and glucose signals that feedback mainly to the hypothalamus to regulate metabolism and fertility. In near future, possible effects of the nutritional status on GnRH regulation can be evaluated by measuring serum or tissue levels of leptin and ghrelin in patiens suffering from infertility. The fact that leptin and ghrelin are antagonistic in their effects on GnRH neurons, their respective agonistic and antagonistic roles make them ideal candidates to use instead of GnRH agonist and antagonist. Similarly, kisspeptin expressing neurons are likely to mediate the well-established link between energy balance and reproductive functions. Exogenous kisspeptin can be used for physiological ovarian hyperstimulation for in-vitro fertilization. Moreover, kisspeptin antagonist therapy can be used for the treatment of postmenapousal women, precocious puberty, PCOS, endometriosis and uterine fibroids. In this review, we will analyze the central mechanisms involved in the integration of metabolic information and their contribution to the control of the reproductive function. Particular attention will be paid to summarize the participation of leptin, kisspeptin, ghrelin, NPY, orexin, urocortin, VIP, insulin, galanin, galanin like peptide, oxytocin, agouti gene-related peptide, and POMC neurons in this process and their possible interactions to contribute to the metabolic control of reproduction.
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Affiliation(s)
- Onder Celik
- Private Clinic, Department of Obstetrics and Gynecology, İzmir, Turkey
| | - Suleyman Aydin
- Firat University, School of Medicine, Department of Medical Biochemistry (Firat Hormones Research Group), 23119 Elazig, Turkey.
| | - Nilufer Celik
- Behcet Uz Children's Hospital, Department of Biochemistry, İzmir, Turkey
| | - Musa Yilmaz
- Firat University, School of Medicine, Department of Medical Biochemistry (Firat Hormones Research Group), 23119 Elazig, Turkey
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Fang P, He B, Shi M, Kong G, Dong X, Zhu Y, Bo P, Zhang Z. The regulative effect of galanin family members on link of energy metabolism and reproduction. Peptides 2015; 71:240-9. [PMID: 26188174 DOI: 10.1016/j.peptides.2015.07.007] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/15/2015] [Revised: 06/27/2015] [Accepted: 07/03/2015] [Indexed: 12/22/2022]
Abstract
It is essential for the species survival that an efficient coordination between energy storage and reproduction through endocrine regulation. The neuropeptide galanin, one of the endocrine hormones, can potently coordinate energy metabolism and the activities of hypothalamic-pituitary-gonadal reproductive axis to adjust synthesis and release of metabolic and reproductive hormones in animals and humans. However, few papers have summarized the regulative effect of the galanin family members on the link of energy storage and reproduction as yet. To address this issue, this review attempts to summarize the current information available about the regulative effect of galanin, galanin-like peptide and alarin on the metabolic and reproductive events, with special emphasis on the interactions between galanin and hypothalamic gonadotropin-releasing hormone, pituitary luteinizing hormone and ovarian hormones. This research line will further deepen our understanding of the physiological roles of the galanin family in regulating the link of energy metabolism and reproduction.
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Affiliation(s)
- Penghua Fang
- Department of Physiology, Nanjing University of Chinese Medicine Hanlin College, Taizhou 225300, China; Jiangsu Key Laboratory of Integrated Traditional Chinese and Western Medicine for Prevention and Treatment of Senile Diseases, Yangzhou University, Yangzhou 225001, China
| | - Biao He
- Jiangsu Key Laboratory of Integrated Traditional Chinese and Western Medicine for Prevention and Treatment of Senile Diseases, Yangzhou University, Yangzhou 225001, China
| | - Mingyi Shi
- Department of Endocrinology, Clinical Medical College, Yangzhou University, Yangzhou 225001, China; Jiangsu Key Laboratory of Integrated Traditional Chinese and Western Medicine for Prevention and Treatment of Senile Diseases, Yangzhou University, Yangzhou 225001, China
| | - Guimei Kong
- Jiangsu Key Laboratory of Integrated Traditional Chinese and Western Medicine for Prevention and Treatment of Senile Diseases, Yangzhou University, Yangzhou 225001, China; Jiangsu Co-innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou University, China
| | - Xiaoyun Dong
- Jiangsu Key Laboratory of Integrated Traditional Chinese and Western Medicine for Prevention and Treatment of Senile Diseases, Yangzhou University, Yangzhou 225001, China; Jiangsu Co-innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou University, China
| | - Yan Zhu
- Department of Endocrinology, Clinical Medical College, Yangzhou University, Yangzhou 225001, China
| | - Ping Bo
- Department of Endocrinology, Clinical Medical College, Yangzhou University, Yangzhou 225001, China; Jiangsu Key Laboratory of Integrated Traditional Chinese and Western Medicine for Prevention and Treatment of Senile Diseases, Yangzhou University, Yangzhou 225001, China.
| | - Zhenwen Zhang
- Department of Endocrinology, Clinical Medical College, Yangzhou University, Yangzhou 225001, China; Jiangsu Key Laboratory of Integrated Traditional Chinese and Western Medicine for Prevention and Treatment of Senile Diseases, Yangzhou University, Yangzhou 225001, China.
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Anderson LL, Scanes CG. Nanobiology and physiology of growth hormone secretion. Exp Biol Med (Maywood) 2012; 237:126-42. [DOI: 10.1258/ebm.2011.011306] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Growth hormone (GH) secretion is controlled by hypothalamic releasing hormones from the median eminence together with hormones and neuropeptides produced by peripheral organs. Secretion of GH involves movement of secretory vesicles along microtubules, transient ‘docking’ with the porosome in the cell membrane and subsequent release of GH. Release of GH is stimulated by GH releasing hormone (GHRH) and inhibited by somatostatin (SRIF). Ghrelin may be functioning to stimulate GH release from somatotropes acting via the GH secretagogue (GHS) receptor (GHSR). However, recent physiological studies militate against this. In addition, ghrelin does influence GH release acting within the hypothalamus. Release of GH from the somatotropes involves the GH-containing secretory granules moving close to the cell surface followed by transitory fusion of the secretory granules with the porosomes located in multiple secretory pits in the cell membrane. Other peptides/proteins can influence GH secretion, particularly in species of non-mammalian vertebrates.
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Affiliation(s)
- Lloyd L Anderson
- Department of Animal Science
- Department of Biomedical Sciences, Iowa State University, Ames, IA 50011
| | - Colin G Scanes
- Department of Biological Sciences, University of Wisconsin, Milwaukee, WI 53211, USA
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Dufourny L, Skinner DC. Distribution of galanin receptor 1-immunoreactive neurons in the ovine hypothalamus: colocalization with GnRH. Brain Res 2005; 1054:73-81. [PMID: 16081052 DOI: 10.1016/j.brainres.2005.06.088] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2005] [Revised: 06/20/2005] [Accepted: 06/25/2005] [Indexed: 10/25/2022]
Abstract
Galanin is implicated in numerous physiological functions, including reproduction. Where and how galanin acts in the brain is poorly understood, but recent evidence suggests that it is predominantly through the GAL-R1 receptor. Using an antibody raised against the third intracellular loop of rat GAL-R1, a region that is highly conserved among species, our first objective was to determine the distribution of cells expressing immunoreactive GAL-R1 in the hypothalamus of the sheep. GAL-R1-immunoreactive cells were spread widely in the ovine diencephalon and overlapped with the known distribution of GnRH neurons. Galanin has been shown to enhance GnRH secretion, but it is not known whether this effect is transduced at the level of the GnRH neuron or is indirect. Thus, our second objective was to establish if GnRH neurons throughout the hypothalamus expressed GAL-R1 receptors and, if so, whether GAL-R1 expression in GnRH neurons was influenced by season, gender and/or stage of the estrous cycle. In rams and ewes during the non-breeding season, only a tenth of the GnRH neurons expressed immunocytochemically detectable GAL-R1 receptors. In contrast, a fifth of the GnRH neurons expressed immunocytochemically detectable GAL-R1 in the luteal phase, whereas only a twentieth expressed GAL-R1 in the follicular phase. These data suggest that galanin may affect a subpopulation of GnRH neurons through the GAL-R1 receptor and that this affect may be modulated by steroids.
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Affiliation(s)
- Laurence Dufourny
- Department of Zoology and Physiology, Department 3166, 1000 E. University Avenue, Laramie, WY 82071, USA
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Estienne MJ, Barb CR. The control of adenohypophysial hormone secretion by amino acids and peptides in swine. Domest Anim Endocrinol 2005; 29:34-42. [PMID: 15927765 DOI: 10.1016/j.domaniend.2005.02.020] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/10/2005] [Revised: 02/10/2005] [Accepted: 02/19/2005] [Indexed: 10/25/2022]
Abstract
Several different amino acids and peptides control secretion of adenohypophysial hormones and this control may be indirect, via the modulation of hypothalamic hormone secretion. Indeed, classical hypothalamic hormones (e.g., gonadotropin-releasing hormone [GnRH], growth hormone-releasing hormone [GHRH], somatostatin, etc.) may be released into the hypothalamo-hypophysial portal vasculature, travel to the adenohypophysis and there stimulate or inhibit secretion of hormones. Alternatively, some amino acids and peptides exert direct stimulatory or inhibitory effects on the adenohypophysis, thereby impacting hormone secretion. In swine, the most extensively studied modulators of adenohypophysial hormone secretion are the excitatory amino acids (ExAA), namely glutamate and aspartate, and the endogenous opioid peptides (EOP). In general, excitatory amino acids stimulate release of luteinizing hormone (LH), follicle-stimulating hormone (FSH), growth hormone (GH), and prolactin (PRL). Secretion of adenohypophysial hormones induced by ExAA is primarily, but perhaps not exclusively, a consequence of action at the central nervous system. By acting primarily at the level of the central nervous system, EOP inhibit LH secretion, stimulate GH release and depending on the animal model studied, exert either stimulatory or inhibitory influences on PRL secretion. However, the EOP also inhibited LH release by direct action on the adenohypophysis. More recently, peptides such as neuropeptide-Y (NPY), orexin-B, ghrelin, galanin, and substance P have been evaluated for possible roles in controlling adenohypophysial hormone secretion in swine. For example, NPY, orexin-B, and ghrelin increased basal GH secretion and modulated the GH response to GHRH, at least in part, by direct action on the adenohypophysis. Secretion of LH was stimulated by orexin-B, galanin, and substance P from porcine pituitary cells in vitro. Because the ExAA and various peptides modulate secretion of adenohypophysial hormones, these compounds may play an important role in regulating swine growth and reproduction.
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Affiliation(s)
- M J Estienne
- Department of Animal and Poultry Sciences, Virginia Polytechnic Institute and State University, Blacksburg, VA 24061, USA.
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Petric N, Kato Y, Elsaesser F. Influence of prenatal testosterone treatment on foetal and prepubertal LHbeta-subunit mRNA and plasma LH concentrations in the female pig. Domest Anim Endocrinol 2004; 27:25-38. [PMID: 15158532 DOI: 10.1016/j.domaniend.2004.01.003] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/08/2003] [Accepted: 01/19/2004] [Indexed: 11/25/2022]
Abstract
The aim of this study was to investigate the potential role of foetal androgens in determining the sexual dimorphism in LH gene expression. Starting on day 30 p.c. pregnant sows were treated i.m. with testosterone propionate (TP) three times at 2-day intervals (TP30 treatment) or received additional TP treatment starting on day 40 p.c. (TP30/40). Sows were allowed to farrow and after frequent blood samples for LH determination were collected prepubertally (6 months) from the female offspring anterior pituitary LHbeta subunit mRNA levels were determined. In Experiment 2 pregnant sows were treated as TP30 before or received similar treatment starting on day 40 p.c. (TP40), but anterior pituitary LHbeta mRNA and plasma LH concentrations were determined at day 80 p.c. TP30 or TP30/40 treatment did not affect mean plasma LH concentrations nor LHbeta mRNA levels at 6 months of age but caused marked masculinization of external genitalia. At day 80 p.c. LHbeta mRNA and plasma LH levels were higher in female than in male foetuses. TP40 treatment suppressed LHbeta mRNA and plasma LH levels while TP30 treatment had no effect on LHbeta mRNA levels but caused masculinization of external genitalia in contrast to TP40. Our findings support the notion that the peak in plasma testosterone observed by others in the male pig foetus 5 weeks p.c. not only determines sexual differentiation of the LH surge mechanism but also LH gene expression in the foetus. The critical period for this process seems to succeed phenotypic differentiation (which appears to be largely completed before day 40 p.c.). The tonic mode of prepubertal LH gene expression and LH secretion in female pigs is not affected greatly by testosterone treatment at the stages of development that were investigated.
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Affiliation(s)
- N Petric
- Federal Agricultural Research Centre (FAL), Institute for Animal Breeding, Mariensee, Neustadt D-31535, Germany
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Dufourny L, Schofield N, Skinner DC. Immunoreactive galanin expression in ovine gonadotropin-releasing hormone neurones: no effects of gender or reproductive status. J Neuroendocrinol 2003; 15:1062-9. [PMID: 14622436 DOI: 10.1046/j.1365-2826.2003.01098.x] [Citation(s) in RCA: 17] [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: 11/20/2022]
Abstract
The neuropeptide, galanin, has been implicated to play a significant role in numerous physiological functions, including reproduction. Studies on several species have shown that galanin enhances gonadotropin-releasing hormone (GnRH)-induced luteinizing hormone secretion. In rodents, a subset of GnRH neurones expresses galanin in a sexually dimorphic manner and it has been suggested that this may underpin the differences in GnRH secretion observed between the sexes. However, there are few data available for other species. Previous studies in sheep have shown that the distribution of GnRH neurones overlaps with galanin cells. The primary objectives of our study were to determine whether GnRH and galanin coexist in the sheep brain and, importantly, if a sex difference is apparent in the colocalization of these two peptides. Using immunocytochemistry coupled to high temperature antigen retrieval, we found that all GnRH neurones in the ovine brain colocalize with galanin. There is also a distinct population of galanin neurones that do not secrete GnRH. In addition, the distribution of galanin-immunoreactive cells was similar to that previously reported for colchicine treated ewes and, in agreement with earlier studies, the number of GnRH neurones did not differ between rams and ewes or between ewes killed at different stages of the oestrous cycle. These results suggest that, in sheep, GnRH and galanin may be cosecreted but the functional significance of this coexpression and possible cosecretion remains to be elucidated.
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Affiliation(s)
- L Dufourny
- University of Wyoming, Department of Zoology and Physiology, Laramie, WY 82071-3166, USA
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Abstract
Recent studies using biotechnological methods have achieved significant advances in our knowledge of molecular mechanisms underlying pituitary gland development and the differentiation of pituitary cytotypes. A large number of neuropeptides have been reported in the adult pituitary gland as well as in the central and peripheral nervous system. The early presence of neuropeptides during pituitary development is reviewed here. Neuromedin U (NmU), galanin and the polypeptide 7B2 have been localised to different endocrine cells of the gland. Their expression seems to be manifold even though it is temporally and spatially regulated. There is now firm immunocytochemical evidence that neuropeptides are present during morphogenesis of the pituitary and can be present simultaneously with all pituitary hormones.
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Affiliation(s)
- Vincenzo Cimini
- Department of Biomorphological and Functional Sciences, Federico II University of Naples, Via Pansini 5, 80131 Naples, Italy.
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