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Mohanty B. Seasonality of Reproduction in a Subtropical Free-Living Finch Amandava amandava: Plasticity of Adenohypophyseal Gonadotropes, Lactotropes, and Thyrotropes. Neuroendocrinology 2024; 114:538-552. [PMID: 38262383 DOI: 10.1159/000536418] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/02/2023] [Accepted: 01/19/2024] [Indexed: 01/25/2024]
Abstract
INTRODUCTION This study sought to decipher the mechanism of transitions between life-history stages in a seasonally reproducing subtropical finch, Amandava amandava delineating the plasticity of the gonadotropes (LH cells), lactotropes (PRL cells), and thyrotropes (TSH cells) in the pituitary gland including the pars tuberalis, with regard to the in situ expression, morphological characteristics, and alteration in the plasma levels of hormones. METHODS Immunohistochemistry of LH, PRL, TSH cells, morphometry and densitometry of expressed hormones (Image J software analysis), and ELISA for plasma hormonal levels were performed. RESULTS LH, PRL, and TSH cells showed remarkable plasticity during the annual seasonal reproductive cycle. In the PT, all the 3 cell types were detected during the breeding phase, with additional detection of the TSH immunoreactivity during the pre-breeding and the PRL immunoreactivity during post-breeding phases. Pars distalis (PD) expressions and the plasma levels of the LH and TSH were at the peak during the breeding phase, but the PRL peak was during the post-breeding phase. In addition to PRL in the neurohypophysis and in the median eminence, hypothalamic PRL, and TSH were also elucidated. CONCLUSIONS This study suggests activation of the gonadal axis by the PT TSH which might transduce seasonal cues, but not specifically photoperiod, in the birds of the tropics/subtropics. Post-breeding phase sustained high plasma TSH and peak plasma PRL might coordinate the transition to the non-breeding phase including the trigger of parental care as the later hormone assigned with. Hypothalamic TSH and PRL might influence events of seasonality through central modulation.
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Affiliation(s)
- Banalata Mohanty
- Department of Zoology, University of Allahabad, Prayagraj, India
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Majumdar G, Yadav G, Singh NS. Photoperiodic physiology of summer breeding birds and a search for the role of eye. Photochem Photobiol Sci 2024; 23:197-212. [PMID: 38038950 DOI: 10.1007/s43630-023-00505-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2023] [Accepted: 11/06/2023] [Indexed: 12/02/2023]
Abstract
Photoperiod regulation of gonadal cycles is well studied and documented in both birds and mammals. Change in photoperiod is considered as the most effective and important cue to time the initiation of the annual physiological cycles in birds. Approaching of long days (as observed in summer months), signal long-day breeding birds to initiation reproduction and other related functions. Birds and other non-mammalian vertebrates use the extraocular photoreceptors which may be present in the mediobasal hypothalamus (MBH) or associated regions to measure the photoperiodic time and so are different from mammals where only the eyes are lone photoreceptive organs. The downstream signaling involves thyroid responsive genes playing a crucial role in mediating photoperiodic signals in both birds and mammals. Role of eyes in the avian seasonal cycle has been a questionable issue with evidences both favoring and negating any role. We propose that morphological as well as physiological data argue that retinal photoreceptors can participate in gonadal cycle, at least in the quail and duck. The present review details the studies of photoneuroendocrine control of gonadal axis in birds and review evidences to decipher the role eyes in photoperiodic mediated physiologies in birds.
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Affiliation(s)
- Gaurav Majumdar
- Department of Zoology, University of Allahabad, Prayagraj, Uttar Pradesh, 211002, India
| | - Garima Yadav
- Department of Biochemistry, University of Allahabad, Prayagraj, Uttar Pradesh, 211002, India
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Kılınç Uğurlu A, Bideci A, Demirel MA, Take Kaplanoğlu G, Dayanır D, Gülbahar Ö, Deveci Bulut TS, Döğer E, Çamurdan MO. Effects of Blue Light on Puberty and Ovary in Female Rats. J Clin Res Pediatr Endocrinol 2023; 15:365-374. [PMID: 37212628 PMCID: PMC10683537 DOI: 10.4274/jcrpe.galenos.2023.2022-12-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/30/2022] [Accepted: 05/09/2023] [Indexed: 05/23/2023] Open
Abstract
Objective This study was designed to examine the effect of blue light exposure and exposure time on puberty in an animal model. Methods Eighteen 21-day-old female Sprague Dawley rats were divided into three equal groups which were: control group (CG); blue light-6 hours (BL-6); and blue light-12 hours (BL-12). CG rats were maintained with 12/12-hour light-dark cycles. The animals in BL-6 and BL-12 were exposed to blue light of wavelength 450-470 nm and intensity of 0.03 uW/cm2 for 6 and 12 hours, respectively. Exposure to blue light continued until the first signs of puberty. Serum follicle stimulating hormone (FSH), luteinizing hormone (LH), estradiol, testosterone, dehydroepiandrosterone sulfate (DHEA-S), leptin and melatonin were measured. Subsequently the ovaries and uterus were examined histomorphologically. Results The median day of puberty start was 38, 32 and 30 for the CG, BL-6, and BL-12 groups, respectively (p=0.001). FSH, testosterone, DHEA-S, and leptin concentrations of all groups were similar. However, LH and estradiol concentrations in BL-6 were higher compared to CG (p=0.02). There was a negative correlation between blue light exposure, exposure time, and melatonin concentrations (r=-0.537, p=0.048). Ovarian tissue was compatible with puberty in all groups. As blue light exposure time increased, capillary dilatation and edema in the ovarian tissue increased. Prolonged exposure was associated with polycystic ovary-like (PCO) morphological changes and apoptosis in granulosa cells. Conclusion These results suggest that exposure to blue light and the duration of exposure induced earlier puberty in female rats. As the duration of blue light exposure increased, PCO-like inflammation, and apoptosis were detected in the ovaries.
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Affiliation(s)
- Aylin Kılınç Uğurlu
- Ankara Bilkent City Hospital, Clinic of Pediatric Endocrinology, Ankara, Turkey
| | - Aysun Bideci
- Gazi University Faculty of Medicine, Department of Pediatric Endocrinology, Ankara, Turkey
| | - Mürşide Ayşe Demirel
- Gazi University Faculty of Pharmacy, Department of Basic Pharmaceutical Sciences, Laboratory Animals Breeding and Experimental Research Center, Ankara, Turkey
| | - Gülnur Take Kaplanoğlu
- Gazi University Faculty of Medicine, Department of Histology and Embryology, Ankara, Turkey
| | - Duygu Dayanır
- Gazi University Faculty of Medicine, Department of Histology and Embryology, Ankara, Turkey
| | - Özlem Gülbahar
- Gazi University Faculty of Medicine, Department of Medical Biochemistry, Ankara, Turkey
| | | | - Esra Döğer
- Gazi University Faculty of Medicine, Department of Pediatric Endocrinology, Ankara, Turkey
| | - Mahmut Orhun Çamurdan
- Gazi University Faculty of Medicine, Department of Pediatric Endocrinology, Ankara, Turkey
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Zhou X, Jiang D, Zhang Z, Shen X, Pan J, Xu D, Tian Y, Huang Y. Expression of GnIH and its effects on follicle development and steroidogenesis in quail ovaries under different photoperiods. Poult Sci 2022; 101:102227. [PMID: 36334429 PMCID: PMC9627100 DOI: 10.1016/j.psj.2022.102227] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2022] [Revised: 09/27/2022] [Accepted: 09/29/2022] [Indexed: 11/21/2022] Open
Abstract
Photoperiod is an important environmental factor that influence seasonal reproduction behavior in bird and GnIH can play a function in this process through the reproductive axis, and some studies suggest that GnIH may have a direct role at the gonadal level. To investigate the expression of GnIH and its effects on follicle development and steroidogenesis in quail ovaries under different photoperiods, 72 healthy laying quails of 8-wk-old were randomly divided into long day (LD) group [16 light (L): 8 dark (D)] (n = 36) and short day (SD) group (8L:16D) (n = 36). Samples were collected from each group on d1, d11, d22, and d36 of the experiment. The result showed that short day treatment upregulated the level of GnIH in the gonads (P < 0.05), decreased the expression level of CYP19A1,3β-HSD, StAR, LHR, and FSHR and increased the expression level of AMH, AMHR2, GDF9, and BMP15 to inhibit follicle development and ovulation, thus affecting the egg production performance of quails. In vitro culture of quail granulosa cells and treatment with different concentrations of GnIH (0, 1, 10, and 100 ng/mL) for 24 h. Result showed that GnIH inhibited the levels of FSHR, LHR, and steroid synthesis pathways in granulosa cells, upregulated the levels of AMHR2, GDF9, and BMP15. The results suggest that the inhibition of follicle development and reduced egg production in quail by short day treatment is due to GnIH acting at the gonadal level, and GnIH affected the steroid synthesis by inhibiting gonadotropin receptors.
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Affiliation(s)
- Xiaoli Zhou
- Zhongkai University of Agriculture and Engineering, Guangzhou 510225, China,Guangdong Key Laboratory of Waterfowl Health Breeding, Guangzhou 510225, China
| | - Danli Jiang
- Zhongkai University of Agriculture and Engineering, Guangzhou 510225, China,Guangdong Key Laboratory of Waterfowl Health Breeding, Guangzhou 510225, China
| | - Zhuoshen Zhang
- Zhongkai University of Agriculture and Engineering, Guangzhou 510225, China,Guangdong Key Laboratory of Waterfowl Health Breeding, Guangzhou 510225, China
| | - Xu Shen
- Zhongkai University of Agriculture and Engineering, Guangzhou 510225, China,Guangdong Key Laboratory of Waterfowl Health Breeding, Guangzhou 510225, China
| | - Jianqiu Pan
- Zhongkai University of Agriculture and Engineering, Guangzhou 510225, China,Guangdong Key Laboratory of Waterfowl Health Breeding, Guangzhou 510225, China
| | - Danning Xu
- Zhongkai University of Agriculture and Engineering, Guangzhou 510225, China,Guangdong Key Laboratory of Waterfowl Health Breeding, Guangzhou 510225, China
| | - Yunbo Tian
- Zhongkai University of Agriculture and Engineering, Guangzhou 510225, China,Guangdong Key Laboratory of Waterfowl Health Breeding, Guangzhou 510225, China
| | - Yunmao Huang
- Zhongkai University of Agriculture and Engineering, Guangzhou 510225, China,Guangdong Key Laboratory of Waterfowl Health Breeding, Guangzhou 510225, China,Corresponding author:
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Ladisa C, Ma Y, Habibi HR. Metabolic Changes During Growth and Reproductive Phases in the Liver of Female Goldfish (Carassius auratus). Front Cell Dev Biol 2022; 10:834688. [PMID: 35295860 PMCID: PMC8919208 DOI: 10.3389/fcell.2022.834688] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2021] [Accepted: 01/31/2022] [Indexed: 11/23/2022] Open
Abstract
Hormones of the brain-pituitary-peripheral axis regulate metabolism, gonadal maturation, and growth in vertebrates. In fish, reproduction requires a significant energy investment to metabolically support the production of hundreds of eggs and billions of sperms in females and males, respectively. This study used an LC-MS-based metabolomics approach to investigate seasonally-related changes in metabolic profile and energy allocation patterns in female goldfish liver. We measured basal metabolic profile in female goldfish at three phases of the reproductive cycle, including 1) Maximum growth period in postovulatory regressed phase, 2) mid recrudescence in fish with developing follicles, and 3) late recrudescence when the ovary contains mature ovulatory follicles. We also investigated changes in the liver metabolism following acute treatments with GnRH and GnIH, known to be involved in controlling reproduction and growth in goldfish. Chemometrics combined with pathway-driven bioinformatics revealed significant changes in the basal and GnRH/GnIH-induced hepatic metabolic profile, indicating that metabolic energy allocation is regulated to support gonadal development and growth at different reproductive cycles. Overall, the findings support the hypothesis that hormonal control of reproduction involves accompanying metabolic changes to energetically support gonadotropic and somatotropic activities in goldfish and other oviparous vertebrates.
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Advancing reproductive neuroendocrinology through research on the regulation of GnIH and on its diverse actions on reproductive physiology and behavior. Front Neuroendocrinol 2022; 64:100955. [PMID: 34767778 DOI: 10.1016/j.yfrne.2021.100955] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/15/2021] [Revised: 10/25/2021] [Accepted: 11/05/2021] [Indexed: 01/03/2023]
Abstract
The discovery of gonadotropin-inhibitory hormone (GnIH) in 2000 has led to a new research era of reproductive neuroendocrinology because, for a long time, researchers believed that only gonadotropin-releasing hormone (GnRH) regulated reproduction as a neurohormone. Later studies on GnIH demonstrated that it acts as a new key neurohormone inhibiting reproduction in vertebrates. GnIH reduces gonadotropin release andsynthesis via the GnIH receptor GPR147 on gonadotropes and GnRH neurons. Furthermore, GnIH inhibits reproductive behavior, in addition to reproductive neuroendocrine function. The modification of the synthesis of GnIH and its release by the neuroendocrine integration of environmental and internal factors has also been demonstrated. Thus, the discovery of GnIH has facilitated advances in reproductive neuroendocrinology. Here, we describe the advances in reproductive neuroendocrinology driven by the discovery of GnIH, research on the effects of GnIH on reproductive physiology and behavior, and the regulatory mechanisms underlying GnIH synthesis and release.
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Regulation of stress response on the hypothalamic-pituitary-gonadal axis via gonadotropin-inhibitory hormone. Front Neuroendocrinol 2022; 64:100953. [PMID: 34757094 DOI: 10.1016/j.yfrne.2021.100953] [Citation(s) in RCA: 24] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/28/2021] [Revised: 09/16/2021] [Accepted: 10/24/2021] [Indexed: 11/21/2022]
Abstract
Under stressful condition, reproductive function is impaired due to the activation of various components of the hypothalamic-pituitaryadrenal (HPA) axis, which can suppress the activity of the hypothalamic-pituitary-gonadal (HPG) axis at multiple levels. A hypothalamic neuropeptide, gonadotropin-inhibitory hormone (GnIH) is a key negative regulator of reproduction that governs the HPG axis. Converging lines of evidence have suggested that different stress types and their duration, such as physical or psychological, and acute or chronic, can modulate the GnIH system. To clarify the sensitivity and reactivity of the GnIH system in response to stress, we summarize and critically review the available studies that investigated the effects of various stressors, such as restraint, nutritional/metabolic and social stress, on GnIH expression and/or its neuronal activity leading to altered HPG action. In this review, we focus on GnIH as the potential novel mediator responsible for stress-induced reproductive dysfunction.
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Kumar P, Wisdom KS, Kumar Ram R, Gireesh-Babu P, Kumar Nayak S, Nagpure NS, Sharma R. Gonadotropin inhibitory hormone receptors (GnIHRs): Molecular characterization and synergistic effect of different drugs in Indian major carp, Labeo catla. Gen Comp Endocrinol 2021; 314:113904. [PMID: 34530001 DOI: 10.1016/j.ygcen.2021.113904] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/02/2021] [Revised: 09/08/2021] [Accepted: 09/09/2021] [Indexed: 11/30/2022]
Abstract
After the discovery of Gonadotropin-inhibitory hormone (GnIH) in birds in 2000, it showed different roles in different vertebrate classes and even in different species of same classes. In birds and mammals, GnIH inhibits the expression of gonadotropins during reproduction, while in fishes it exerts both inhibitory and stimulatory effect on reproduction. The current study evaluates the role of GnIH during reproduction in Labeo catla. The partial cDNA sequence of GnIHR1 and GnIHR3 receptor genes was identified by degenerate PCR. The mRNA expression analysis of GnIHRs during different reproductive phases showed that the expression of all three GnIH receptor genes is highest during spawning phase. The expression of GnIH receptors is detected in both brain and gonads except for GnIHR3 which only expressed in gonads. The in vivo experiments with GnIH antagonist, RF313 drastically reduced the expression level of reproduction related genes like LH, FSH, and GnRH at 1 h post-injection. In another experiment the surge induced by cGnIH-III peptide on gonadotropins gene expression is further increased when co-injected with LHRHa. However, co-injection of melatonin along with cGnIH-III peptide had opposite effects. These results showed that the GnIH/GnIHRs system has positive effect on reproduction in L. catla.
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Affiliation(s)
- Pravesh Kumar
- College of Fisheries, Dr. Rajendra Prasad Central Agricultural University, Pusa, Bihar, India.
| | - K S Wisdom
- ICAR-Central Institute of Fisheries Education, Mumbai 400061, India
| | - Roshan Kumar Ram
- College of Fisheries, Dr. Rajendra Prasad Central Agricultural University, Pusa, Bihar, India
| | | | | | - N S Nagpure
- ICAR-Central Institute of Fisheries Education, Mumbai 400061, India
| | - Rupam Sharma
- ICAR-Central Institute of Fisheries Education, Mumbai 400061, India
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Ouyang H, Yang B, Lao Y, Tang J, Tian Y, Huang Y. Photoperiod affects the laying performance of the mountain duck by regulating endocrine hormones and gene expression. Vet Med Sci 2021; 7:1899-1906. [PMID: 33955171 PMCID: PMC8464274 DOI: 10.1002/vms3.508] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2020] [Revised: 01/18/2021] [Accepted: 04/12/2021] [Indexed: 12/18/2022] Open
Abstract
Light mainly affects animal reproductive performance through the hypothalamus‐ pituitary‐gonadal axis, but the specific regulating mechanism is not yet clear in duck. To reveal the effects of light on the laying performance of ducks and its possible regulatory mechanisms, Shanma ducks at 52 weeks age were divided into three group treated with different photoperiods of 16 hr (control group), 24 hr (long‐photoperiod group, LP), and 8 hr (short‐photoperiod group, SP). Laying performance, endocrine‐related hormones and gene expression of three groups were compared. The results showed that laying performance was greatest in the LP group; including laying rate, average egg weight and feed‐egg ratio. Compared to the SP group, GnIH plasma concentration was decreased in the LP group, whilst FSH was increased in the LP group. GnIHR gene expression in the pituitary and large yellow follicles were downregulated in the LP group. The expression of Mel‐a in large white follicles, and Mel‐b and Mel‐c in the hypothalamus were also downregulated in the LP group. Altogether these results suggest that extended photoperiods may promote the laying performance of ducks by inhibiting the secretion of GnIH and the expression of GnIHR and melatonin receptor genes.
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Affiliation(s)
- Hongjia Ouyang
- Guangdong Province Key Laboratory of Waterfowl Healthy Breeding, College of Animal Science and Technology, Zhongkai University of Agriculture and Engineering, Guangzhou, China
| | - Bo Yang
- Guangdong Province Key Laboratory of Waterfowl Healthy Breeding, College of Animal Science and Technology, Zhongkai University of Agriculture and Engineering, Guangzhou, China
| | - Yongcong Lao
- Guangdong Province Key Laboratory of Waterfowl Healthy Breeding, College of Animal Science and Technology, Zhongkai University of Agriculture and Engineering, Guangzhou, China
| | - Jun Tang
- Guangdong Province Key Laboratory of Waterfowl Healthy Breeding, College of Animal Science and Technology, Zhongkai University of Agriculture and Engineering, Guangzhou, China
| | - Yunbo Tian
- Guangdong Province Key Laboratory of Waterfowl Healthy Breeding, College of Animal Science and Technology, Zhongkai University of Agriculture and Engineering, Guangzhou, China
| | - Yunmao Huang
- Guangdong Province Key Laboratory of Waterfowl Healthy Breeding, College of Animal Science and Technology, Zhongkai University of Agriculture and Engineering, Guangzhou, China
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Tsutsui K, Ubuka T. Gonadotropin-inhibitory hormone (GnIH): A new key neurohormone controlling reproductive physiology and behavior. Front Neuroendocrinol 2021; 61:100900. [PMID: 33450199 DOI: 10.1016/j.yfrne.2021.100900] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/05/2020] [Revised: 01/04/2021] [Accepted: 01/10/2021] [Indexed: 11/17/2022]
Abstract
The discovery of novel neurohormones is important for the advancement of neuroendocrinology. In early 1970s, gonadotropin-releasing hormone (GnRH), a hypothalamic neuropeptide that promotes gonadotropin release, was identified to be an endogenous neurohormone in mammals. In 2000, thirty years later, another hypothalamic neuropeptide, gonadotropin-inhibitory hormone (GnIH), that inhibits gonadotropin release, was found in quail. GnIH acts via GPR147 and inhibits gonadotropin release and synthesis and reproductive function in birds through actions on GnRH neurons in the hypothalamus and pituitary gonadotrophs. Later, GnIH was found in other vertebrates including humans. GnIH studies have advanced the progress of reproductive neuroendocrinology. Furthermore, recent GnIH studies have indicated that abnormal changes in GnIH expression may cause pubertal disorder and reproductive dysfunction. Here, we describe GnIH discovery and its impact on the progress of reproductive neuroendocrinology. This review also highlights advancement and perspective of GnIH studies on drug development for pubertal disorder and reproductive dysfunction. (149/150).
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Affiliation(s)
- Kazuyoshi Tsutsui
- Department of Biology and Center for Medical Life Science, Waseda University, Shinjuku-ku, Tokyo 162-8480, Japan; Graduate School of Integrated Sciences for Life, Hiroshima University, Kagamiyama 1-7-1, Higashi-Hiroshima 739-8521, Japan.
| | - Takayoshi Ubuka
- Department of Biology and Center for Medical Life Science, Waseda University, Shinjuku-ku, Tokyo 162-8480, Japan
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Anjum S, Khattak MNK, Tsutsui K, Krishna A. RF-amide related peptide-3 (RFRP-3): a novel neuroendocrine regulator of energy homeostasis, metabolism, and reproduction. Mol Biol Rep 2021; 48:1837-1852. [PMID: 33566226 DOI: 10.1007/s11033-021-06198-z] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2020] [Accepted: 01/28/2021] [Indexed: 11/29/2022]
Abstract
A hypothalamic neuropeptide, RF-amide related peptide-3 (RFRP-3), the mammalian ortholog of the avian gonadotropin-inhibitory hormone (GnIH) has inhibitory signals for reproductive axis via G-protein coupled receptor 147 in mammals. Moreover, RFRP-3 has orexigenic action but the mechanism involved in energy homeostasis and glucose metabolism is not yet known. Though, the RFRP-3 modulates orexigenic action in co-operation with other neuropeptides, which regulates metabolic cues in the hypothalamus. Administration of GnIH/RFRP-3 suppresses plasma luteinizing hormone, at the same time stimulates feeding behavior in birds and mammals. Likewise, in the metabolically deficient conditions, its expression is up-regulated suggests that RFRP-3 contributes to the integration of energy balance and reproduction. However, in many other metabolic conditions like induced diabetes and high-fat diet obesity, etc. its role is still not clear while, RFRP-3 induces the glucose homeostasis by adipocytes is reported. The physiological role of RFRP-3 in metabolic homeostasis and the metabolic effects of RFRP-3 signaling in pharmacological studies need a detailed discussion. Further studies are required to find out whether RFRP-3 is associated with restricted neuroendocrine function observed in type II diabetes mellitus, aging, or sub-fertility. In this context, the current review is focused on the role of RFRP-3 in the above-mentioned mechanisms. Studies from search engines including PubMed, Google Scholar, and science.gov are included after following set inclusion/exclusion criteria. As a developing field few mechanisms are still inconclusive, however, based on the available information RFRP-3 seems to be a putative tool in future treatment strategies towards metabolic disease.
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Affiliation(s)
- Shabana Anjum
- Department of Zoology, Banaras Hindu University, Varanasi, Uttar Pradesh, India
- Sharjah Institute of Medical Research, University of Sharjah, Sharjah, United Arab Emirates
| | | | - Kazuyoshi Tsutsui
- Graduate School of Integrated Sciences for Life, Hiroshima University, Kagamiyama 1-7-1, Higashi-Hiroshima, 739-8521, Japan
| | - Amitabh Krishna
- Department of Zoology, Banaras Hindu University, Varanasi, Uttar Pradesh, India
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Soni R, Haldar C, Mohini Chaturvedi C. Retinal and extra-retinal photoreceptor responses and reproductive performance of Japanese quail (Coturnix coturnix japonica) following exposure to different photoperiodic regime. Gen Comp Endocrinol 2021; 302:113667. [PMID: 33221313 DOI: 10.1016/j.ygcen.2020.113667] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/25/2019] [Revised: 11/04/2020] [Accepted: 11/13/2020] [Indexed: 11/17/2022]
Abstract
Japanese quail is a truly photoperiodic avian species. In general long days are gonado-stimulatory and short days are gonado-inhibitory for this poultry bird. To investigate the correlation of retinal and extra-retinal photoreceptors with different photoperiodic conditions quail were divided into 2 groups and kept under long day (16L: 8D) and short day (8L: 16D) condition separately to develop photosensitivity and scotosensitivity respectively. Transfer of long day quail to intermediate day-length (13.5L: 10.5D) developed photorefractoriness (relative) and prolonged exposure to short photoperiodic conditions led the birds to develop scotorefractoriness. Increased expression of mRNA and immunosignaling of photoreceptors rhodopsin, transducin in eye and hypothalamus while decreased mRNA expression of melatonin receptors (Mel1b, Mel1c) were noted in the eyes of photosensitive (PS) and scotorefractory (SR) quail compared to photorefractory (PR) and scotosensitive (SS) birds respectively. Decreased expression of hypothalamic GnIH and melatonin receptors mRNA was observed in PS and SR birds compared to PR and SS birds respectively. Modulation of retinal and extra retinal photoreceptors leads to increased spermatogenesis as well as mRNA expression of steroidogenic genes and androgen receptor in the testis of sexually active PS and SR quail. These results led us to conclude that gonadal stimulation in PS as well as SR quail is outcome of activated retinal and extra retinal photoreceptors which lowered melatonin receptors and GnIH expression. Contrarily testicular inhibition in PR and SS is the outcome of decreased photoperception. It is suggested that decreased photoperception in SS quail increases after prolong exposure of the short day (in SR) leading to increased activity of HPG axis.
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Affiliation(s)
- Richa Soni
- Department of Zoology, Banaras Hindu University, Varanasi 221005, India
| | - Chandana Haldar
- Department of Zoology, Banaras Hindu University, Varanasi 221005, India
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Gomes PRL, Motta-Teixeira LC, Gallo CC, Carmo Buonfiglio DD, Camargo LSD, Quintela T, Reiter RJ, Amaral FGD, Cipolla-Neto J. Maternal pineal melatonin in gestation and lactation physiology, and in fetal development and programming. Gen Comp Endocrinol 2021; 300:113633. [PMID: 33031801 DOI: 10.1016/j.ygcen.2020.113633] [Citation(s) in RCA: 24] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/07/2020] [Accepted: 09/20/2020] [Indexed: 12/21/2022]
Abstract
Pregnancy and lactation are reproductive processes that rely on physiological adaptations that should be timely and adequately triggered to guarantee both maternal and fetal health. Pineal melatonin is a hormone that presents daily and seasonal variations that synchronizes the organism's physiology to the different demands across time through its specific mechanisms and ways of action. The reproductive system is a notable target for melatonin as it actively participates on reproductive physiology and regulates the hypothalamus-pituitary-gonads axis, influencing gonadotropins and sexual hormones synthesis and release. For its antioxidant properties, melatonin is also vital for the oocytes and spermatozoa quality and viability, and for blastocyst development. Maternal pineal melatonin blood levels increase during pregnancy and triggers the maternal physiological alterations in energy metabolism both during pregnancy and lactation to cope with the energy demands of both periods and to promote adequate mammary gland development. Moreover, maternal melatonin freely crosses the placenta and is the only source of this hormone to the fetus. It importantly times the conceptus physiology and influences its development and programing of several functions that depend on neural and brain development, ultimately priming adult behavior and energy and glucose metabolism. The present review aims to explain the above listed melatonin functions, including the potential alterations observed in the progeny gestated under maternal chronodisruption and/or hypomelatoninemia.
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Affiliation(s)
- Patrícia Rodrigues Lourenço Gomes
- Neurobiology Lab, Department of Physiology and Biophysics, 1524 Prof. Lineu Prestes Ave., Institute of Biomedical Sciences, Bldg 1, Lab 118, University of São Paulo, São Paulo 05508-000, Brazil
| | - Lívia Clemente Motta-Teixeira
- Neurobiology Lab, Department of Physiology and Biophysics, 1524 Prof. Lineu Prestes Ave., Institute of Biomedical Sciences, Bldg 1, Lab 118, University of São Paulo, São Paulo 05508-000, Brazil
| | - Camila Congentino Gallo
- Pineal Neurobiology Lab, Department of Physiology, 862 Botucatu St., 5th floor, Federal University of São Paulo, São Paulo 04023-901, Brazil.
| | - Daniella do Carmo Buonfiglio
- Neurobiology Lab, Department of Physiology and Biophysics, 1524 Prof. Lineu Prestes Ave., Institute of Biomedical Sciences, Bldg 1, Lab 118, University of São Paulo, São Paulo 05508-000, Brazil
| | - Ludmilla Scodeler de Camargo
- Pineal Neurobiology Lab, Department of Physiology, 862 Botucatu St., 5th floor, Federal University of São Paulo, São Paulo 04023-901, Brazil.
| | - Telma Quintela
- CICS-UBI - Health Sciences Research Center, Infante D. Henrique Ave, University of Beira Interior, Covilhã 6200-506, Portugal.
| | - Russel J Reiter
- Department of Cell Systems and Anatomy, Long School of Medicine, 7703 Floyd Curl Drive, UT Health San Antonio, San Antonio, TX 78229, USA.
| | - Fernanda Gaspar do Amaral
- Pineal Neurobiology Lab, Department of Physiology, 862 Botucatu St., 5th floor, Federal University of São Paulo, São Paulo 04023-901, Brazil.
| | - José Cipolla-Neto
- Neurobiology Lab, Department of Physiology and Biophysics, 1524 Prof. Lineu Prestes Ave., Institute of Biomedical Sciences, Bldg 1, Lab 118, University of São Paulo, São Paulo 05508-000, Brazil.
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Teo CH, Phon B, Parhar I. The Role of GnIH in Biological Rhythms and Social Behaviors. Front Endocrinol (Lausanne) 2021; 12:728862. [PMID: 34566893 PMCID: PMC8461181 DOI: 10.3389/fendo.2021.728862] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/22/2021] [Accepted: 08/23/2021] [Indexed: 12/30/2022] Open
Abstract
Gonadotropin-inhibitory hormone (GnIH) was first discovered in the Japanese quail, and peptides with a C-terminal LPXRFamide sequence, the signature protein structure defining GnIH orthologs, are well conserved across vertebrate species, including fish, reptiles, amphibians, avians, and mammals. In the mammalian brain, three RFamide-related proteins (RFRP-1, RFRP-2, RFRP-3 = GnIH) have been identified as orthologs to the avian GnIH. GnIH is found primarily in the hypothalamus of all vertebrate species, while its receptors are distributed throughout the brain including the hypothalamus and the pituitary. The primary role of GnIH as an inhibitor of gonadotropin-releasing hormone (GnRH) and pituitary gonadotropin release is well conserved in mammalian and non-mammalian species. Circadian rhythmicity of GnIH, regulated by light and seasons, can influence reproductive activity, mating behavior, aggressive behavior, and feeding behavior. There is a potential link between circadian rhythms of GnIH, anxiety-like behavior, sleep, stress, and infertility. Therefore, in this review, we highlight the functions of GnIH in biological rhythms, social behaviors, and reproductive and non-reproductive activities across a variety of mammalian and non-mammalian vertebrate species.
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Tsutsui K, Ubuka T. Discovery of gonadotropin-inhibitory hormone (GnIH), progress in GnIH research on reproductive physiology and behavior and perspective of GnIH research on neuroendocrine regulation of reproduction. Mol Cell Endocrinol 2020; 514:110914. [PMID: 32535039 DOI: 10.1016/j.mce.2020.110914] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/08/2019] [Revised: 06/05/2020] [Accepted: 06/08/2020] [Indexed: 01/08/2023]
Abstract
Based on extensive studies on gonadotropin-releasing hormone (GnRH) it was assumed that GnRH is the only hypothalamic neurohormone regulating gonadotropin release in vertebrates. In 2000, however, Tsutsui's group discovered gonadotropin-inhibitory hormone (GnIH), a novel hypothalamic neuropeptide that inhibits gonadotropin release, in quail. Subsequent studies by Tsutsui's group demonstrated that GnIH is conserved among vertebrates, acting as a new key neurohormone regulating reproduction. GnIH inhibits gonadotropin synthesis and release through actions on gonadotropes and GnRH neurons via GnIH receptor, GPR147. Thus, GnRH is not the sole hypothalamic neurohormone controlling vertebrate reproduction. The following studies by Tsutsui's group have further demonstrated that GnIH has several important functions in addition to the control of reproduction. Accordingly, GnIH has drastically changed our understanding about reproductive neuroendocrinology. This review summarizes the discovery of GnIH, progress in GnIH research on reproductive physiology and behavior and perspective of GnIH research on neuroendocrine regulation of reproduction.
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Affiliation(s)
- Kazuyoshi Tsutsui
- Laboratory of Integrative Brain Sciences, Department of Biology and Center for Medical Life Science, Waseda University, Tokyo, 162-8480, Japan.
| | - Takayoshi Ubuka
- Laboratory of Integrative Brain Sciences, Department of Biology and Center for Medical Life Science, Waseda University, Tokyo, 162-8480, Japan
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Paullada-Salmerón JA, Cowan ME, Loentgen GH, Aliaga-Guerrero M, Zanuy S, Mañanós EL, Muñoz-Cueto JA. The gonadotropin-inhibitory hormone system of fish: The case of sea bass (Dicentrarchus labrax). Gen Comp Endocrinol 2019; 279:184-195. [PMID: 30923006 DOI: 10.1016/j.ygcen.2019.03.015] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/31/2018] [Revised: 03/12/2019] [Accepted: 03/23/2019] [Indexed: 11/21/2022]
Abstract
Gonadotropin-inhibitory hormone (GnIH) is a hypothalamic neuropeptide belonging to the RFamide peptide family that was first discovered in quail by Tsutsui and co-workers in the year 2000. Since then, different GnIH orthologues have been identified in all vertebrate groups, from agnathans to mammals. These GnIH genes synthesize peptide precursors that encompass two to four C-terminal LPXRFamide peptides. Functional and behavioral studies carried out in birds and mammals have demonstrated a clear inhibitory role of GnIH on GnRH and gonadotropin synthesis and secretion as well as on aggressive and sexual behavior. However, the effects of Gnih orthologues in reproduction remain controversial in fish with both stimulatory and inhibitory actions being reported. In this paper, we will review the main findings obtained in our laboratory on the Gnih system of the European sea bass, Dicentrarchus labrax. The sea bass gnih gene encodes two putative Gnih peptides (sbGnih1 and sbGnih2), and is expressed in the olfactory bulbs/telencephalon, diencephalon, midbrain tegmentum, rostral rhombencephalon, retina and testis. The immunohistochemical study performed using specific antibodies developed in our laboratory revealed Gnih-immunoreactive (ir) perikarya in the same central areas and Gnih-ir fibers that profusely innervated the brain and pituitary of sea bass. Moreover, in vivo studies revealed the inhibitory role of centrally- and peripherally-administered Gnih in the reproductive axis of male sea bass, by acting at the brain (on gnrh and kisspeptin expression), pituitary (on gnrh receptors and gonadotropin synthesis and release) and gonadal (on androgen secretion and gametogenesis) levels. Our results have revealed the existence of a functional Gnih system in sea bass, and have provided evidence of the differential actions of the two Gnih peptides on the reproductive axis of this species, the main inhibitory role in the brain and pituitary being exerted by the sbGnih2 peptide. Recent studies developed in our laboratory also suggest that Gnih might be involved in the transduction of photoperiod and temperature information to the reproductive axis, as well as in the modulation of daily and seasonal rhythmic processes in sea bass.
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Affiliation(s)
- José Antonio Paullada-Salmerón
- Department of Biology, Faculty of Marine and Environmental Sciences and INMAR, University of Cádiz, CEIMAR, Puerto Real (Cádiz), Spain.
| | - Mairi E Cowan
- Department of Biology, Faculty of Marine and Environmental Sciences and INMAR, University of Cádiz, CEIMAR, Puerto Real (Cádiz), Spain
| | - Guillaume H Loentgen
- Department of Biology, Faculty of Marine and Environmental Sciences and INMAR, University of Cádiz, CEIMAR, Puerto Real (Cádiz), Spain
| | - María Aliaga-Guerrero
- Department of Biology, Faculty of Marine and Environmental Sciences and INMAR, University of Cádiz, CEIMAR, Puerto Real (Cádiz), Spain
| | - Silvia Zanuy
- Institute of Aquaculture of Torre de la Sal, CSIC, Castellón, Spain
| | | | - José Antonio Muñoz-Cueto
- Department of Biology, Faculty of Marine and Environmental Sciences and INMAR, University of Cádiz, CEIMAR, Puerto Real (Cádiz), Spain.
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Trivedi AK, Sur S, Sharma A, Taufique ST, Gupta NJ, Kumar V. Temperature alters the hypothalamic transcription of photoperiod responsive genes in induction of seasonal response in migratory redheaded buntings. Mol Cell Endocrinol 2019; 493:110454. [PMID: 31121264 DOI: 10.1016/j.mce.2019.110454] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/23/2019] [Revised: 05/13/2019] [Accepted: 05/19/2019] [Indexed: 12/12/2022]
Abstract
We investigated the temperature effects on hypothalamic transcription of genes involved in the induction of photoperiodic response in redheaded buntings. Birds were exposed at 22 and 38 °C to 13-h long photoperiods (LP), with controls at 22 °C on 8-h short photoperiods (SP). At 22 °C, compared to SP, we found higher tshb, eya3 and dio2 and low dio3 and gnih mRNA expressions after a week of LP; concomitant with testis recrudescence this confirmed buntings' responsiveness to LP-induced photostimulation. tshb, dio2 and gnrh mRNA levels were further increased by 2.5 weeks of LP at 38 °C. Temperature sensitive trpm8, but not trpv4, bdnf or adcyap1 also showed LP-induced expression at 22 °C. Concomitant changes in dnmt3b and tet2 mRNA expressions further suggested epigenetic modification of temperature influence on photoperiodic responses. These results demonstrate the role of temperature in hypothalamic molecular regulation of the photoperiodic gonadal response in seasonally breeding birds.
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Affiliation(s)
| | - Sayantan Sur
- Department of Zoology, University of Delhi, Delhi, 110007, India
| | - Aakansha Sharma
- Department of Zoology, University of Delhi, Delhi, 110007, India
| | | | - Neelu Jain Gupta
- Department of Zoology, University of Delhi, Delhi, 110007, India
| | - Vinod Kumar
- Department of Zoology, University of Delhi, Delhi, 110007, India.
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18
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Abstract
Organisms use changes in photoperiod for seasonal reproduction to maximize the survival of their offspring. Birds have sophisticated seasonal mechanisms and are therefore excellent models for studying these phenomena. Birds perceive light via deep-brain photoreceptors and long day–induced thyroid-stimulating hormone (TSH, thyrotropin) in the pars tuberalis of the pituitary gland (PT), which cause local thyroid hormone activation within the mediobasal hypothalamus. The local bioactive thyroid hormone controls seasonal gonadotropin-releasing hormone secretion and subsequent gonadotropin secretion. In mammals, the eyes are believed to be the only photoreceptor organ, and nocturnal melatonin secretion triggers an endocrine signal that communicates information about the photoperiod to the PT to regulate TSH. In contrast, in Salmonidae fish the input pathway to the neuroendocrine output pathway appears to be localized in the saccus vasculosus. Thus, comparative analysis is an effective way to uncover the universality and diversity of fundamental traits in various organisms.
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Affiliation(s)
- Yusuke Nakane
- Institute of Transformative Bio-Molecules (WPI-ITbM), Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8601, Japan
- Laboratory of Animal Integrative Physiology, Graduate School of Bioagricultural Sciences, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8601, Japan
| | - Takashi Yoshimura
- Institute of Transformative Bio-Molecules (WPI-ITbM), Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8601, Japan
- Laboratory of Animal Integrative Physiology, Graduate School of Bioagricultural Sciences, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8601, Japan
- Avian Bioscience Research Center, Graduate School of Bioagricultural Sciences, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8601, Japan
- Division of Seasonal Biology, National Institute for Basic Biology, Myodaiji, Okazaki 444-8585, Japan
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19
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Son YL, Ubuka T, Tsutsui K. Molecular Mechanisms of Gonadotropin-Inhibitory Hormone (GnIH) Actions in Target Cells and Regulation of GnIH Expression. Front Endocrinol (Lausanne) 2019; 10:110. [PMID: 30858828 PMCID: PMC6397841 DOI: 10.3389/fendo.2019.00110] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/22/2018] [Accepted: 02/06/2019] [Indexed: 11/13/2022] Open
Abstract
Since gonadotropin-inhibitory hormone (GnIH) was discovered in 2000 as the first hypothalamic neuropeptide that actively inhibits gonadotropin release, researches conducted for the last 18 years have demonstrated that GnIH acts as a pronounced negative regulator of reproduction. Inhibitory effect of GnIH on reproduction is mainly accomplished at hypothalamic-pituitary levels; gonadotropin-releasing hormone (GnRH) neurons and gonadotropes are major targets of GnIH action based on the morphological interaction with GnIH neuronal fibers and the distribution of GnIH receptor. Here, we review molecular studies mainly focusing on the signal transduction pathway of GnIH in target cells, GnRH neurons, and gonadotropes. The use of well-defined cellular model systems allows the mechanistic study of signaling pathway occurring in target cells by demonstrating the direct cause-and-effect relationship. The insights gained through studying molecular mechanism of GnIH action contribute to deeper understanding of the mechanism of how GnIH communicates with other neuronal signaling systems to control our reproductive function. Reproductive axis closely interacts with other endocrine systems, thus GnIH expression levels would be changed by adrenal and thyroid status. We also briefly review molecular studies investigating the regulatory mechanisms of GnIH expression to understand the role of GnIH as a mediator between adrenal, thyroid and gonadal axes.
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Affiliation(s)
- You Lee Son
- Laboratory of Photobiology, Department of Ophthalmology, Keio University School of Medicine, Tokyo, Japan
- Laboratory of Integrative Brain Sciences, Department of Biology and Center for Medical Life Science, Waseda University, Tokyo, Japan
- *Correspondence: You Lee Son
| | - Takayoshi Ubuka
- Laboratory of Integrative Brain Sciences, Department of Biology and Center for Medical Life Science, Waseda University, Tokyo, Japan
| | - Kazuyoshi Tsutsui
- Laboratory of Integrative Brain Sciences, Department of Biology and Center for Medical Life Science, Waseda University, Tokyo, Japan
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20
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GUH YJ, TAMAI TK, YOSHIMURA T. The underlying mechanisms of vertebrate seasonal reproduction. PROCEEDINGS OF THE JAPAN ACADEMY. SERIES B, PHYSICAL AND BIOLOGICAL SCIENCES 2019; 95:343-357. [PMID: 31406058 PMCID: PMC6766453 DOI: 10.2183/pjab.95.025] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/25/2019] [Accepted: 04/24/2019] [Indexed: 06/01/2023]
Abstract
Animals make use of changes in photoperiod to adapt their physiology to the forthcoming breeding season. Comparative studies have contributed to our understanding of the mechanisms of seasonal reproduction in vertebrates. Birds are excellent models for studying these phenomena because of their rapid and dramatic responses to changes in photoperiod. Deep brain photoreceptors in birds perceive and transmit light information to the pars tuberalis (PT) in the pituitary gland, where the thyroid-stimulating hormone (TSH) is produced. This PT-TSH locally increases the level of the bioactive thyroid hormone T3 via the induction of type 2 deiodinase production in the mediobasal hypothalamus, and an increased T3 level, in turn, controls seasonal gonadotropin-releasing hormone secretion. In mammals, the eyes are the only photoreceptive structure, and nocturnal melatonin secretion encodes day-length information and regulates the PT-TSH signaling cascade. In Salmonidae, the saccus vasculosus plays a pivotal role as a photoperiodic sensor. Together, these studies have uncovered the universality and diversity of fundamental traits in vertebrates.
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Affiliation(s)
- Ying-Jey GUH
- Institute of Transformative Bio-Molecules (WPI-ITbM), Nagoya University, Nagoya, Aichi, Japan
- Division of Seasonal Biology, National Institute for Basic Biology, Okazaki, Aichi, Japan
| | - Takako K TAMAI
- Institute of Transformative Bio-Molecules (WPI-ITbM), Nagoya University, Nagoya, Aichi, Japan
| | - Takashi YOSHIMURA
- Institute of Transformative Bio-Molecules (WPI-ITbM), Nagoya University, Nagoya, Aichi, Japan
- Division of Seasonal Biology, National Institute for Basic Biology, Okazaki, Aichi, Japan
- Laboratory of Integrative Physiology, Graduate School of Bioagricultural Sciences, Nagoya University, Nagoya, Aichi, Japan
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21
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Di Yorio MP, Muñoz-Cueto JA, Paullada-Salmerón JA, Somoza GM, Tsutsui K, Vissio PG. The Gonadotropin-Inhibitory Hormone: What We Know and What We Still Have to Learn From Fish. Front Endocrinol (Lausanne) 2019; 10:78. [PMID: 30837949 PMCID: PMC6389629 DOI: 10.3389/fendo.2019.00078] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/03/2018] [Accepted: 01/28/2019] [Indexed: 12/16/2022] Open
Abstract
Gonadotropin-inhibitory hormone, GnIH, is named because of its function in birds and mammals; however, in other vertebrates this function is not yet clearly established. More than half of the vertebrate species are teleosts. This group is characterized by the 3R whole genome duplication, a fact that could have been responsible for the great phenotypic complexity and great variability in reproductive strategies and sexual behavior. In this context, we revise GnIH cell bodies and fibers distribution in adult brains of teleosts, discuss its relationship with GnRH variants and summarize the few reports available about the ontogeny of the GnIH system. Considering all the information presented in this review, we propose that in teleosts, GnIH could have other functions beyond reproduction or act as an integrative signal in the reproductive process. However, further studies are required in order to clarify the role of GnIH in this group including its involvement in development, a key stage that strongly impacts on adult life.
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Affiliation(s)
- María P. Di Yorio
- Departamento de Biodiversidad y Biología Experimental, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Buenos Aires, Argentina
- Instituto de Biodiversidad y Biología Experimental y Aplicada (IBBEA), CONICET-Universidad de Buenos Aires, Buenos Aires, Argentina
| | - José A. Muñoz-Cueto
- Department of Biology, Faculty of Marine and Environmental Sciences, University of Cádiz, Puerto Real, Spain
- Marine Research Institute (INMAR), Marine Campus of International Excellence (CEIMAR) and Agrifood Campus of International Excellence (ceiA3), Puerto Real, Spain
| | - José A. Paullada-Salmerón
- Department of Biology, Faculty of Marine and Environmental Sciences, University of Cádiz, Puerto Real, Spain
- Marine Research Institute (INMAR), Marine Campus of International Excellence (CEIMAR) and Agrifood Campus of International Excellence (ceiA3), Puerto Real, Spain
| | - Gustavo M. Somoza
- Instituto Tecnológico de Chascomús (CONICET-UNSAM), Chascomús, Argentina
| | - Kazuyoshi Tsutsui
- Department of Biology and Center for Medical Life Science, Waseda University, Tokyo, Japan
| | - Paula G. Vissio
- Departamento de Biodiversidad y Biología Experimental, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Buenos Aires, Argentina
- Instituto de Biodiversidad y Biología Experimental y Aplicada (IBBEA), CONICET-Universidad de Buenos Aires, Buenos Aires, Argentina
- *Correspondence: Paula G. Vissio
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Mohammad Rezazadeh F, Saedi S, Rahmanifar F, Namavar MR, Dianatpour M, Tanideh N, Akhlaghi A, Niazi A, Arabi Monfared A, Tsutsui K, Jafarzadeh Shirazi MR, Tamadon A. Fast free of acrylamide clearing tissue (FACT) for clearing, immunolabelling and three-dimensional imaging of partridge tissues. Microsc Res Tech 2018; 81:1374-1382. [DOI: 10.1002/jemt.23078] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2018] [Revised: 04/29/2018] [Accepted: 06/07/2018] [Indexed: 11/11/2022]
Affiliation(s)
| | - Saman Saedi
- Department of Animal Science, College of Agriculture; Shiraz University; Shiraz Iran
| | - Farhad Rahmanifar
- Department of Basic Sciences, School of Veterinary Medicine; Shiraz University; Shiraz Iran
| | - Mohammad Reza Namavar
- Clinical Neurology Research Center, and Histomorphometry & Stereology Research Center; Shiraz University of Medical Sciences; Shiraz Iran
| | - Mehdi Dianatpour
- Stem Cells Technology Research Center; Shiraz University of Medical Sciences; Shiraz Iran
- Department of Medical Genetics, School of Pharmacy; Shiraz University of Medical Sciences; Shiraz Iran
| | - Nader Tanideh
- Stem Cells Technology Research Center; Shiraz University of Medical Sciences; Shiraz Iran
- Department of Pharmacology, School of Medicine; Shiraz University of Medical Sciences; Shiraz Iran
| | - Amir Akhlaghi
- Department of Animal Science, College of Agriculture; Shiraz University; Shiraz Iran
| | - Ali Niazi
- Institute of Biotechnology; Shiraz University; Shiraz Iran
| | - Ali Arabi Monfared
- Central Research Laboratory; Shiraz University of Medical Sciences; Shiraz Iran
| | - Kazuyoshi Tsutsui
- Department of Biology; Waseda University; Shinjuku-ku Tokyo, 162-8480 Japan
| | | | - Amin Tamadon
- The Persian Gulf Marine Biotechnology Research Center; The Persian Gulf Biomedical Sciences Research Institute, Bushehr University of Medical Sciences; Bushehr Iran
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23
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Tsutsui K, Ubuka T. How to Contribute to the Progress of Neuroendocrinology: Discovery of GnIH and Progress of GnIH Research. Front Endocrinol (Lausanne) 2018; 9:662. [PMID: 30483217 PMCID: PMC6241250 DOI: 10.3389/fendo.2018.00662] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/05/2018] [Accepted: 10/23/2018] [Indexed: 01/14/2023] Open
Abstract
It is essential to discover novel neuropeptides that regulate the functions of pituitary, brain and peripheral secretory glands for the progress of neuroendocrinology. Gonadotropin-releasing hormone (GnRH), a hypothalamic neuropeptide stimulating gonadotropin release was isolated and its structure was determined by Schally's and Guillemin's groups at the beginning of the 1970s. It was subsequently shown that GnRH is highly conserved among vertebrates. GnRH was assumed the sole hypothalamic neuropeptide that regulates gonadotropin release in vertebrates based on extensive studies of GnRH over the following three decades. However, in 2000, Tsutsui's group isolated and determined the structure of a novel hypothalamic neuropeptide, which inhibits gonadotropin release, in quail, an avian species, and named it gonadotropin-inhibitory hormone (GnIH). Following studies by Tsutsui's group demonstrated that GnIH is highly conserved among vertebrates, from humans to agnathans, and acts as a key neuropeptide inhibiting reproduction. Intensive research on GnIH demonstrated that GnIH inhibits gonadotropin synthesis and release by acting on gonadotropes and GnRH neurons via GPR147 in birds and mammals. Fish GnIH also regulates gonadotropin release according to its reproductive condition, indicating the conserved role of GnIH in the regulation of the hypothalamic-pituitary-gonadal (HPG) axis in vertebrates. Therefore, we can now say that GnRH is not the only hypothalamic neuropeptide controlling vertebrate reproduction. In addition, recent studies by Tsutsui's group demonstrated that GnIH acts in the brain to regulate behaviors, including reproductive behavior. The 18 years of GnIH research with leading laboratories in the world have significantly advanced our knowledge of the neuroendocrine control mechanism of reproductive physiology and behavior as well as interactions of the HPG, hypothalamic-pituitary-adrenal and hypothalamic-pituitary-thyroid axes. This review describes how GnIH was discovered and GnIH research progressed in this new research era of reproductive neuroendocrinology.
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Affiliation(s)
- Kazuyoshi Tsutsui
- Laboratory of Integrative Brain Sciences, Department of Biology and Center for Medical Life Science, Waseda University, Tokyo, Japan
| | - Takayoshi Ubuka
- Laboratory of Integrative Brain Sciences, Department of Biology and Center for Medical Life Science, Waseda University, Tokyo, Japan
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24
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Tsutsui K, Osugi T, Son YL, Ubuka T. Review: Structure, function and evolution of GnIH. Gen Comp Endocrinol 2018; 264:48-57. [PMID: 28754274 DOI: 10.1016/j.ygcen.2017.07.024] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/27/2017] [Revised: 07/21/2017] [Accepted: 07/25/2017] [Indexed: 12/27/2022]
Abstract
Neuropeptides that possess the Arg-Phe-NH2 motif at their C-termini (i.e., RFamide peptides) have been characterized in the nervous system of both invertebrates and vertebrates. In vertebrates, RFamide peptides make a family and consist of the groups of gonadotropin-inhibitory hormone (GnIH), neuropeptide FF (NPFF), prolactin-releasing peptide (PrRP), kisspeptin (kiss1 and kiss2), and pyroglutamylated RFamide peptide/26RFamide peptide (QRFP/26RFa). It now appears that these vertebrate RFamide peptides exert important neuroendocrine, behavioral, sensory, and autonomic functions. In 2000, GnIH was discovered as a novel hypothalamic RFamide peptide inhibiting gonadotropin release in quail. Subsequent studies have demonstrated that GnIH acts on the brain and pituitary to modulate reproductive physiology and behavior across vertebrates. To clarify the origin and evolution of GnIH, the existence of GnIH was investigated in agnathans, the most ancient lineage of vertebrates, and basal chordates, such as tunicates and cephalochordates (represented by amphioxus). This review first summarizes the structure and function of GnIH and other RFamide peptides, in particular NPFF having a similar C-terminal structure of GnIH, in vertebrates. Then, this review describes the evolutionary origin of GnIH based on the studies in agnathans and basal chordates.
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Affiliation(s)
- Kazuyoshi Tsutsui
- Laboratory of Integrative Brain Sciences, Department of Biology and Center for Medical Life Science, Waseda University, Tokyo 162-8480, Japan.
| | - Tomohiro Osugi
- Bioorganic Research Institute, Suntory Foundation for Life Sciences, Kyoto 619-0284, Japan
| | - You Lee Son
- Laboratory of Integrative Brain Sciences, Department of Biology and Center for Medical Life Science, Waseda University, Tokyo 162-8480, Japan
| | - Takayoshi Ubuka
- Brain Research Institute Monash Sunway, Jeffrey Cheah School of Medicine and Health Sciences, Monash University Malaysia, Bandar Sunway, Selangor 47500, Malaysia
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Kriegsfeld LJ, Jennings KJ, Bentley GE, Tsutsui K. Gonadotrophin-inhibitory hormone and its mammalian orthologue RFamide-related peptide-3: Discovery and functional implications for reproduction and stress. J Neuroendocrinol 2018; 30:e12597. [PMID: 29624758 PMCID: PMC6263162 DOI: 10.1111/jne.12597] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/26/2017] [Revised: 03/26/2018] [Accepted: 03/28/2018] [Indexed: 02/06/2023]
Abstract
At the turn of the millennium, a neuropeptide with pronounced inhibitory actions on avian pituitary gonadotrophin secretion was identified and named gonadotrophin-inhibitory hormone (GnIH). Across bird species, GnIH acts at the level of the pituitary and the gonadotrophin-releasing hormone (GnRH) neuronal system to inhibit reproduction. Subsequent to this initial discovery, orthologues of GnIH have been identified and characterised across a broad range of species. In many vertebrates, the actions of GnIH and its orthologues serve functional roles analogous to those seen in birds. In other cases, GnIH and its orthologues exhibit more diverse actions dependent on sex, species, season and reproductive condition. The present review highlights the discovery and functional implications of GnIH across species, focusing on research domains in which the significance of this neuropeptide has been explored most.
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Affiliation(s)
- Lance J. Kriegsfeld
- Department of Psychology, University of California, Berkeley, California 94720, USA
- The Helen Wills Neuroscience Institute, University of California, Berkeley, California 94720, USA
- Corresponding Author: Lance J. Kriegsfeld, Ph.D. Neurobiology Laboratory, Department of Psychology and The Helen Wills Neuroscience Institute, University of California at Berkeley, Berkeley, California 94720-1650, USA, Phone: (510) 642-5148; Fax: (510) 642-5293;
| | - Kimberly J. Jennings
- Department of Psychology, University of California, Berkeley, California 94720, USA
| | - George E. Bentley
- The Helen Wills Neuroscience Institute, University of California, Berkeley, California 94720, USA
- Department of Integrative Biology, University of California, Berkeley, California 94720, USA
| | - Kazuyoshi Tsutsui
- Laboratory of Integrative Brain Sciences, Department of Biology, Waseda University, and Center for Medical Life Science of Waseda University, 2-2 Wakamatsu-cho, Shinjuku-ku, Tokyo 162-8480, Japan
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Banerjee S, Shahin S, Chaturvedi CM. Age dependent variations in the deep brain photoreceptors (DBPs), GnRH-GnIH system and testicular steroidogenesis in Japanese quail, Coturnix coturnix japonica. Exp Gerontol 2018; 108:7-17. [PMID: 29580815 DOI: 10.1016/j.exger.2018.03.018] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2017] [Revised: 03/17/2018] [Accepted: 03/22/2018] [Indexed: 12/19/2022]
Abstract
The complex physiology of aging involves a number of molecular and biochemical events, manifested as signs of senescence. Japanese quail is a very unique and advantageous model to study the signs and symptoms of senescence in the central and peripheral modules of HPG axis. In the present study, we have investigated the age dependent variations in hypothalamic deep brain photoreceptors (DBPs), central GnRH-I/II-GnIH-Mel1cR system, testicular GnRH-GnIH system, testicular steroidogenic genes and proteins, androgen receptor (AR) and serum testosterone level in quail of different age groups [3-wk (sexually immature), 6-wk (sexually mature and crossed the puberty), 16-wk (adult, sexually active and showing full breeding phase) and 144-wk (aged)]. Findings of our present study showed the differential expression of these genes/proteins in quail of different age groups. The low levels of the DBPs, GnRH-I, GnIH, Mel1cR in hypothalamus and GnRH-II in midbrain, significantly decreased testicular GnRH/GnRH-R-GnIH, steroidogenic genes/proteins and serum testosterone were observed in immature quail. The significantly increased expression of opsins in the DBPs, GnRH-I, GnIH, Mel1cR in hypothalamus and GnRH-II in midbrain influences the testicular GnRH-GnIH and stimulate the testicular steroidogenesis in mature and adult quail. In aged quail, the significantly decreased levels of hypothalamic DBPs, GnRH-I, GnIH, Mel1cR and midbrain GnRH-II modulates the testicular GnRH-GnIH and further suppresses the genes/proteins involved in steroidogenesis and results in reduced serum testosterone. Hence, it can be concluded from our findings that the testicular steroidogenesis and its neuroendocrine regulation varies with age, in Japanese quail.
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Affiliation(s)
- Somanshu Banerjee
- Department of Zoology, Banaras Hindu University, Varanasi 221005, India
| | - Saba Shahin
- Department of Zoology, Banaras Hindu University, Varanasi 221005, India
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Wood S, Loudon A. The pars tuberalis: The site of the circannual clock in mammals? Gen Comp Endocrinol 2018; 258:222-235. [PMID: 28669798 DOI: 10.1016/j.ygcen.2017.06.029] [Citation(s) in RCA: 38] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/02/2017] [Revised: 06/23/2017] [Accepted: 06/29/2017] [Indexed: 12/12/2022]
Abstract
Accurate timing and physiological adaptation to anticipate seasonal changes are an essential requirement for an organism's survival. In contrast to all other environmental cues, photoperiod offers a highly predictive signal that can be reliably used to activate a seasonal adaptive programme at the correct time of year. Coupled to photoperiod sensing, it is apparent that many organisms have evolved innate long-term timekeeping systems, allowing reliable anticipation of forthcoming environmental changes. The fundamental biological processes giving rise to innate long-term timing, with which the photoperiod-sensing pathway engages, are not known for any organism. There is growing evidence that the pars tuberalis (PT) of the pituitary, which acts as a primary transducer of photoperiodic input, may be the site of the innate long-term timer or "circannual clock". Current research has led to the proposition that the PT-specific thyrotroph may act as a seasonal calendar cell, driving both hypothalamic and pituitary endocrine circuits. Based on this research we propose that the mechanistic basis for the circannual rhythm appears to be deeply conserved, driven by a binary switching cell based accumulator, analogous to that proposed for development. We review the apparent conservation of function and pathways to suggest that these broad principles may apply across the vertebrate lineage and even share characteristics with processes driving seasonal adaptation in plants.
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Affiliation(s)
- Shona Wood
- Faculty of Biology, Medicine and Health, School of Medical Sciences, University of Manchester, A.V. Hill Building, Oxford Road, Manchester M13 9PT, UK.
| | - Andrew Loudon
- Faculty of Biology, Medicine and Health, School of Medical Sciences, University of Manchester, A.V. Hill Building, Oxford Road, Manchester M13 9PT, UK
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Munley KM, Rendon NM, Demas GE. Neural Androgen Synthesis and Aggression: Insights From a Seasonally Breeding Rodent. Front Endocrinol (Lausanne) 2018; 9:136. [PMID: 29670576 PMCID: PMC5893947 DOI: 10.3389/fendo.2018.00136] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/29/2017] [Accepted: 03/15/2018] [Indexed: 11/24/2022] Open
Abstract
Aggression is an essential social behavior that promotes survival and reproductive fitness across animal systems. While research on the neuroendocrine mechanisms underlying this complex behavior has traditionally focused on the classic neuroendocrine model, in which circulating gonadal steroids are transported to the brain and directly mediate neural circuits relevant to aggression, recent studies have suggested that this paradigm is oversimplified. Work on seasonal mammals that exhibit territorial aggression outside of the breeding season, such as Siberian hamsters (Phodopus sungorus), has been particularly useful in elucidating alternate mechanisms. These animals display elevated levels of aggression during the non-breeding season, in spite of gonadal regression and reduced levels of circulating androgens. Our laboratory has provided considerable evidence that the adrenal hormone precursor dehydroepiandrosterone (DHEA) is important in maintaining aggression in both male and female Siberian hamsters during the non-breeding season, a mechanism that appears to be evolutionarily-conserved in some seasonal rodent and avian species. This review will discuss research on the neuroendocrine mechanisms of aggression in Siberian hamsters, a species that displays robust neural, physiological, and behavioral changes on a seasonal basis. Furthermore, we will address how these findings support a novel neuroendocrine pathway for territorial aggression in seasonal animals, in which adrenal DHEA likely serves as an essential precursor for neural androgen synthesis during the non-breeding season.
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Tsutsui K, Son YL, Kiyohara M, Miyata I. Discovery of GnIH and Its Role in Hypothyroidism-Induced Delayed Puberty. Endocrinology 2018; 159:62-68. [PMID: 28938445 DOI: 10.1210/en.2017-00300] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/29/2017] [Accepted: 09/11/2017] [Indexed: 11/19/2022]
Abstract
It is known that hypothyroidism delays puberty in mammals. Interaction between the hypothalamo-pituitary-thyroid (HPT) and hypothalamo-pituitary-gonadal (HPG) axes may be important processes in delayed puberty. Gonadotropin-inhibitory hormone (GnIH) is a newly discovered hypothalamic neuropeptide that inhibits gonadotropin synthesis and release in quail. It now appears that GnIH is conserved across various mammals and primates, including humans, and inhibits reproduction. We have further demonstrated that GnIH is involved in pubertal delay induced by thyroid dysfunction in female mice. Hypothyroidism delays pubertal onset with the increase in hypothalamic GnIH expression and the decrease in circulating gonadotropin and estradiol levels. Thyroid status regulates GnIH expression by epigenetic modification of the GnIH promoter region. Furthermore, knockout of GnIH gene abolishes the effect of hypothyroidism on delayed pubertal onset. Accordingly, it is considered that GnIH is a mediator of pubertal disorder induced by thyroid dysfunction. This is a novel function of GnIH that interacts between the HPT-HPG axes in pubertal onset delay. This mini-review summarizes the structure, expression, and function of GnIH and highlights the action of GnIH in pubertal disorder induced by thyroid dysfunction.
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Affiliation(s)
- Kazuyoshi Tsutsui
- Laboratory of Integrative Brain Sciences, Department of Biology, Waseda University, Shinjuku-ku, Tokyo, Japan
- Center for Medical Life Science of Waseda University, Shinjuku-ku, Tokyo, Japan
| | - You Lee Son
- Laboratory of Integrative Brain Sciences, Department of Biology, Waseda University, Shinjuku-ku, Tokyo, Japan
- Center for Medical Life Science of Waseda University, Shinjuku-ku, Tokyo, Japan
- Laboratory of Photobiology, Department of Ophthalmology, Keio University School of Medicine, Shinjuku-ku, Tokyo, Japan
| | - Mika Kiyohara
- Laboratory of Integrative Brain Sciences, Department of Biology, Waseda University, Shinjuku-ku, Tokyo, Japan
- Center for Medical Life Science of Waseda University, Shinjuku-ku, Tokyo, Japan
- Department of Pediatrics, Jikei University School of Medicine, Minato-ku, Tokyo, Japan
| | - Ichiro Miyata
- Department of Pediatrics, Jikei University School of Medicine, Minato-ku, Tokyo, Japan
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Dixit AS, Byrsat S. Photoperiodic control of GnRH-I expression in seasonal reproduction of the Eurasian tree sparrow. Photochem Photobiol Sci 2018; 17:934-945. [DOI: 10.1039/c8pp00153g] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Day length has been shown to be a major source of temporal information regulating seasonal reproduction in the Eurasian tree sparrow (Passer montanus).
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Surkin PN, Di Rosso ME, Correa F, Elverdin JC, Genaro AM, De Laurentiis A, Fernández-Solari J. Participation of hypothalamic CB1 receptors in reproductive axis disruption during immune challenge. J Neuroendocrinol 2017; 29. [PMID: 28665507 DOI: 10.1111/jne.12499] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/15/2017] [Revised: 06/26/2017] [Accepted: 06/26/2017] [Indexed: 12/24/2022]
Abstract
Immune challenge inhibits reproductive function and endocannabinoids (eCB) modulate sexual hormones. However, no studies have been performed to assess whether the eCB system mediates the inhibition of hormones that control reproduction as a result of immune system activation during systemic infections. For that reason, we evaluated the participation of the hypothalamic cannabinoid receptor CB1 on the hypothalamic-pituitary-gonadal (HPG) axis activity in rats submitted to immune challenge. Male adult rats were treated i.c.v. administration with a CB1 antagonist/inverse agonist (AM251) (500 ng/5 μL), followed by an i.p. injection of lipopolysaccharide (LPS) (5 mg/kg) 15 minutes later. Plasmatic, hypothalamic and adenohypophyseal pro-inflammatory cytokines, hormones and neuropeptides were assessed 90 or 180 minutes post-LPS. The plasma concentration of tumour necrosis factor α and adenohypophyseal mRNA expression of Tnfα and Il1β increased 90 and 180 minutes post i.p. administration of LPS. However, cytokine mRNA expression in the hypothalamus increased only 180 minutes post-LPS, suggesting an inflammatory delay in this organ. CB1 receptor blockade with AM251 increased LPS inflammatory effects, particularly in the hypothalamus. LPS also inhibited the HPG axis by decreasing gonadotrophin-releasing hormone hypothalamic content and plasma levels of luteinising hormone and testosterone. These disruptor effects were accompanied by decreased hypothalamic Kiss1 mRNA expression and prostaglandin E2 content, as well as by increased gonadotrophin-inhibitory hormone (Rfrp3) mRNA expression. All these disruptive effects were prevented by the presence of AM251. In summary, our results suggest that, in male rats, eCB mediate immune challenge-inhibitory effects on reproductive axis at least partially via hypothalamic CB1 activation. In addition, this receptor also participates in homeostasis recovery by modulating the inflammatory process taking place after LPS administration.
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Affiliation(s)
- P N Surkin
- Facultad de Odontología, Universidad de Buenos Aires, Buenos Aires, Argentina
- Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Buenos Aires, Argentina
| | - M E Di Rosso
- Pontificia Universidad Católica Argentina (UCA), Consejo Nacional de Investigaciones Científicas y Técnicas, Instituto de Investigaciones Biomédicas (BIOMED), Buenos Aires, Argentina
| | - F Correa
- Facultad de Medicina, Centro de Estudios Farmacológicos y Botánicos, Universidad de Buenos Aires, Consejo Nacional de Investigaciones Científicas y Técnicas, Buenos Aires, Argentina
| | - J C Elverdin
- Facultad de Odontología, Universidad de Buenos Aires, Buenos Aires, Argentina
| | - A M Genaro
- Pontificia Universidad Católica Argentina (UCA), Consejo Nacional de Investigaciones Científicas y Técnicas, Instituto de Investigaciones Biomédicas (BIOMED), Buenos Aires, Argentina
- Facultad de Medicina, Universidad de Buenos Aires, Buenos Aires, Argentina
| | - A De Laurentiis
- Facultad de Odontología, Universidad de Buenos Aires, Buenos Aires, Argentina
- Facultad de Medicina, Centro de Estudios Farmacológicos y Botánicos, Universidad de Buenos Aires, Consejo Nacional de Investigaciones Científicas y Técnicas, Buenos Aires, Argentina
| | - J Fernández-Solari
- Facultad de Odontología, Universidad de Buenos Aires, Buenos Aires, Argentina
- Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Buenos Aires, Argentina
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George JT, Hendrikse M, Veldhuis JD, Clarke IJ, Anderson RA, Millar RP. Effect of gonadotropin-inhibitory hormone on luteinizing hormone secretion in humans. Clin Endocrinol (Oxf) 2017; 86:731-738. [PMID: 28186349 DOI: 10.1111/cen.13308] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/17/2016] [Revised: 01/09/2017] [Accepted: 02/03/2017] [Indexed: 01/01/2023]
Abstract
BACKGROUND Gonadotropin-inhibitory hormone (GnIH, human homologue of RFRP-3) suppresses gonadotropin secretion in animal models, but its effects have not been studied in the human. OBJECTIVE We tested the hypotheses that exogenous GnIH inhibits LH secretion (i) in postmenopausal women and (ii) in men concurrently administered exogenous kisspeptin. DESIGN Following in vitro and in vivo preclinical studies to functionally characterize the GnIH peptide, a dose-finding study (human GnIH: 1·5-150 μg/kg/h, iv for 3 h) was undertaken, and 50 μg/kg/h selected for further evaluation. Five postmenopausal women were administered 50 μg/kg/h iv infusion for 3 h or vehicle on two separate days. Four men were administered kisspeptin-10 (0·3 μg/kg iv bolus) with simultaneous infusion of GnIH (50 μg/kg/h, iv for 3 h) or vehicle. PARTICIPANTS Healthy postmenopausal women (mean age 58 ± 2 years, LH: 30·8 ± 2·9 IU/l, FSH: 78·7 ± 6·4 IU/l, oestradiol: <50 pmol/l) and men (39·8 ± 2·1 years, mean total testosterone 12·1 ± 1·8 nmol/l, LH 2·2 ± 0·2 IU/l). PRIMARY OUTCOME Change in area under curve (AUC) of LH during GnIHvs vehicle. RESULTS During GnIH administration in postmenopausal women, LH secretion decreased (ΔAUC: -9·9 ± 1·8 IU/3 h) vs vehicle (ΔAUC: -0·5 ± 1·7 IU/3 h; P = 0·02). Kisspeptin-10-stimulated LH responses in men were not affected by GnIH co-administration (60-min AUC of LH 6·2 ± 0·8 IU/h with kisspeptin-10 alone, 6·3 ± 1·0 IU/h, kisspeptin-10 with GnIH, P = 0·72). Exogenous GnIH was well tolerated, with no adverse events reported. CONCLUSIONS Gonadotropin-inhibitory hormone decreased LH secretion in postmenopausal women in this first-in-human study. Kisspeptin-stimulated LH secretion in men was not inhibited during concomitant administration of GnIH.
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Affiliation(s)
- J T George
- MRC Centre for Reproductive Health, The Queen's Medical Research Institute, University of Edinburgh, Edinburgh, UK
- Diabetes Trials Unit, Endocrinology and Metabolism, Oxford Centre for Diabetes, Oxford, UK
| | - M Hendrikse
- Department of Medical Biochemistry and Institute for Infectious Diseases and Molecular Medicine, University of Cape Town, Observatory, South Africa
| | - J D Veldhuis
- Endocrine Research Unit, Center for Translational Science Activities, Mayo Clinic, Rochester, MN, USA
| | - I J Clarke
- Department of Physiology, School of Biomedical Sciences, Monash University, Clayton, Victoria, Australia
| | - R A Anderson
- MRC Centre for Reproductive Health, The Queen's Medical Research Institute, University of Edinburgh, Edinburgh, UK
| | - R P Millar
- Department of Medical Biochemistry and Institute for Infectious Diseases and Molecular Medicine, University of Cape Town, Observatory, South Africa
- Mammal Research Institute and Centre for Neuroendocrinology, University of Pretoria, Pretoria, South Africa
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Cowan M, Paullada-Salmerón JA, López-Olmeda JF, Sánchez-Vázquez FJ, Muñoz-Cueto JA. Effects of pinealectomy on the neuroendocrine reproductive system and locomotor activity in male European sea bass, Dicentrarchus labrax. Comp Biochem Physiol A Mol Integr Physiol 2017; 207:1-12. [PMID: 28188883 DOI: 10.1016/j.cbpa.2017.02.008] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2016] [Revised: 02/03/2017] [Accepted: 02/05/2017] [Indexed: 12/19/2022]
Abstract
The seasonally changing photoperiod controls the timing of reproduction in most fish species, however, the transduction of this photoperiodic information to the reproductive axis is still unclear. This study explored the potential role of two candidate neuropeptide systems, gonadotropin-inhibitory hormone (Gnih) and kisspeptin, as mediators between the pineal organ (a principle transducer of photoperiodic information) and reproductive axis in male European sea bass, Dicentrarchus labrax. Two seven-day experiments of pinealectomy (Px) were performed, in March (end of reproductive season) and August (resting season). Effects of Px and season on the brain expression of gnih (sbgnih) and its receptor (sbgnihr), kisspeptins (kiss1, kiss2) and their receptors (kissr2, kissr3) and gonadotropin-releasing hormone (gnrh1, gnrh2, gnrh3) and the main brain receptor (gnrhr-II-2b) genes, plasma melatonin levels and locomotor activity rhythms were examined. Results showed that Px reduced night-time plasma melatonin levels. Gene expression analyses demonstrated a sensitivity of the Gnih system to Px in March, with a reduction in sbgnih in the mid-hindbrain, a region with bilateral connections to the pineal organ. In August, kiss2 levels increased in Px animals but not in controls. Significant differences in expression were observed for diencephalic sbgnih, sbgnihr, kissr3 and tegmental gnrh2 between seasons. Recordings of locomotor activity following surgery revealed a change from light-synchronised to free-running rhythmic behavior. Altogether, the Gnih and Kiss2 sensitivity to Px and seasonal differences observed for Gnih and its receptor, Gnrh2, and the receptor for Kiss2 (Kissr3), suggested they could be mediators involved in the relay between environment and seasonal reproduction.
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Affiliation(s)
- Mairi Cowan
- Department of Biology, Faculty of Marine and Environmental Sciences, University of Cádiz, Marine Campus of International Excellence (CEIMAR) and Agrifood Campus of International Excellence (ceiA3), E-11510 Puerto Real, Spain; INMAR-CACYTMAR Research Institutes, Puerto Real University Campus, E-11510 Puerto Real, Spain.
| | - José A Paullada-Salmerón
- Department of Biology, Faculty of Marine and Environmental Sciences, University of Cádiz, Marine Campus of International Excellence (CEIMAR) and Agrifood Campus of International Excellence (ceiA3), E-11510 Puerto Real, Spain; INMAR-CACYTMAR Research Institutes, Puerto Real University Campus, E-11510 Puerto Real, Spain
| | - José Fernando López-Olmeda
- Department of Physiology, Faculty of Biology, University of Murcia, Regional Campus of International Excellence "Campus Mare Nostrum", E-30100 Murcia, Spain
| | - Francisco Javier Sánchez-Vázquez
- Department of Physiology, Faculty of Biology, University of Murcia, Regional Campus of International Excellence "Campus Mare Nostrum", E-30100 Murcia, Spain
| | - José A Muñoz-Cueto
- Department of Biology, Faculty of Marine and Environmental Sciences, University of Cádiz, Marine Campus of International Excellence (CEIMAR) and Agrifood Campus of International Excellence (ceiA3), E-11510 Puerto Real, Spain; INMAR-CACYTMAR Research Institutes, Puerto Real University Campus, E-11510 Puerto Real, Spain.
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Dixit AS, Singh NS, Byrsat S. Role of GnIH in photoperiodic regulation of seasonal reproduction in the Eurasian tree sparrow. J Exp Biol 2017; 220:3742-3750. [DOI: 10.1242/jeb.164541] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2017] [Accepted: 08/10/2017] [Indexed: 12/15/2022]
Abstract
Seasonal reproductive cycles of most birds are regulated by photoperiod via neuroendocrine control. GnIH in hypothalamus has been reported to act as neuroendocrine integrator of photoperiodic cues. In this study, both captive and field investigations were carried out to understand the effects of photoperiod and seasonality on GnIH expression in subtropical tree sparrows. Monthly observations on GnIH mRNA and peptide expressions in wild birds over a year revealed significant increase in GnIH mRNA level and number of GnIH-ir neurons during the nonbreeding season when compared to their expressions in the breeding season. GnIH-ir neurons were found primarily in paraventricular nucleus (PVN) with their fibers projecting into median eminence and some other areas of brain. In an eight month long experiment, birds exposed to short days had higher GnIH expression compared to birds on long days regardless of sampling month. Long day birds with regressed testes had similar GnIH levels compared to short day birds. Though the number of GnIH peptide expressing neurons ran almost parallel to the levels of GnIH mRNA, they were found inversely related to gonadal size in both sexes under natural and artificial photoperiodic conditions. These results clearly indicate inhibitory role of GnIH in photoperiodic regulation of seasonal reproduction in the tree sparrow.
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Affiliation(s)
- Anand S. Dixit
- Department of Zoology, North-Eastern Hill University, Shillong-22, India
| | - Namram S. Singh
- Department of Zoology, Cotton University, Guwahati-01, India
| | - Sanborlang Byrsat
- Department of Zoology, North-Eastern Hill University, Shillong-22, India
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Muñoz-Cueto JA, Paullada-Salmerón JA, Aliaga-Guerrero M, Cowan ME, Parhar IS, Ubuka T. A Journey through the Gonadotropin-Inhibitory Hormone System of Fish. Front Endocrinol (Lausanne) 2017; 8:285. [PMID: 29163357 PMCID: PMC5670112 DOI: 10.3389/fendo.2017.00285] [Citation(s) in RCA: 60] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/24/2017] [Accepted: 10/10/2017] [Indexed: 12/22/2022] Open
Abstract
Gonadotropin-inhibitory hormone (GnIH) is a hypothalamic neuropeptide that belongs to the RFamide peptide family and was first identified in the quail brain. From the discovery of avian GnIH, orthologous GnIH peptides have been reported in a variety of vertebrates, including mammals, amphibians, teleosts and agnathans, but also in protochordates. It has been clearly established that GnIH suppresses reproduction in avian and mammalian species through its inhibitory actions on brain GnRH and pituitary gonadotropins. In addition, GnIH also appears to be involved in the regulation of feeding, growth, stress response, heart function and social behavior. These actions are mediated via G protein-coupled GnIH receptors (GnIH-Rs), of which two different subtypes, GPR147 and GPR74, have been described to date. With around 30,000 species, fish represent more than one-half of the total number of recognized living vertebrate species. In addition to this impressive biological diversity, fish are relevant because they include model species with scientific and clinical interest as well as many exploited species with economic importance. In spite of this, the study of GnIH and its physiological effects on reproduction and other physiological processes has only been approached in a few fish species, and results obtained are in some cases conflicting. In this review, we summarize the information available in the literature on GnIH sequences identified in fish, the distribution of GnIH and GnIH-Rs in central and peripheral tissues, the physiological actions of GnIH on the reproductive brain-pituitary-gonadal axis, as well as other reported effects of this neuropeptide, and existing knowledge on the regulatory mechanisms of GnIH in fish.
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Affiliation(s)
- José A. Muñoz-Cueto
- Faculty of Environmental and Marine Sciences, Department of Biology, University of Cádiz, Marine Campus of International Excellence (CEIMAR) and Agrifood Campus of International Excellence (ceiA3), Puerto Real, Spain
- Marine Research Institute (INMAR) – Andalusian Centre of Marine Science and Technology (CACYTMAR), University of Cádiz, Puerto Real, Spain
- *Correspondence: José A. Muñoz-Cueto,
| | - José A. Paullada-Salmerón
- Faculty of Environmental and Marine Sciences, Department of Biology, University of Cádiz, Marine Campus of International Excellence (CEIMAR) and Agrifood Campus of International Excellence (ceiA3), Puerto Real, Spain
- Marine Research Institute (INMAR) – Andalusian Centre of Marine Science and Technology (CACYTMAR), University of Cádiz, Puerto Real, Spain
| | - María Aliaga-Guerrero
- Faculty of Environmental and Marine Sciences, Department of Biology, University of Cádiz, Marine Campus of International Excellence (CEIMAR) and Agrifood Campus of International Excellence (ceiA3), Puerto Real, Spain
- Marine Research Institute (INMAR) – Andalusian Centre of Marine Science and Technology (CACYTMAR), University of Cádiz, Puerto Real, Spain
| | - Mairi E. Cowan
- Faculty of Environmental and Marine Sciences, Department of Biology, University of Cádiz, Marine Campus of International Excellence (CEIMAR) and Agrifood Campus of International Excellence (ceiA3), Puerto Real, Spain
- Marine Research Institute (INMAR) – Andalusian Centre of Marine Science and Technology (CACYTMAR), University of Cádiz, Puerto Real, Spain
| | - Ishwar S. Parhar
- Jeffrey Cheah School of Medicine and Health Science, Brain Research Institute, Monash University Malaysia, Bandar Sunway, Malaysia
| | - Takayoshi Ubuka
- Jeffrey Cheah School of Medicine and Health Science, Brain Research Institute, Monash University Malaysia, Bandar Sunway, Malaysia
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Ullah R, Shen Y, Zhou YD, Huang K, Fu JF, Wahab F, Shahab M. Expression and actions of GnIH and its orthologs in vertebrates: Current status and advanced knowledge. Neuropeptides 2016; 59:9-20. [PMID: 27255391 DOI: 10.1016/j.npep.2016.05.004] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/02/2016] [Revised: 05/01/2016] [Accepted: 05/23/2016] [Indexed: 12/20/2022]
Abstract
The physiology of reproduction is very complex and is regulated by multiple factors, including a number of hypothalamic neuropeptides. In last few decades, various neuropeptides have been discovered to be involved in stimulation or inhibition of reproduction. In 2000, Tsutsui and colleagues uncovered gonadotropin-inhibitory hormone (GnIH), a neuropeptide generating inhibitory drive to the reproductive axis, in the brain of Coturnix quail. Afterward, GnIH orthologs were discovered in other vertebrates from fish to mammals including human. In these vertebrates, all the discovered GnIH and its ortholgs have LPXRFamide (X=L or Q) sequence at C-terminus. GnIH orthologs of mammals and primates are also termed as RFamide-related peptide (RFRP)-1 and -3 that too have an LPXRFamide (X=L or Q) motif at their C-terminus. GnIH and its orthologs form a member of the RFamide peptide family. GnIH signals via its canonical G protein coupled receptor 147 (GPR147). Both GnIH and GPR147 are expressed in hypothalamus and other brain regions. Besides actions through the hypothalamic GnRH and kisspeptinergic neurons, GnIH-GPR147 signaling exerts inhibitory effect on the reproductive axis via pituitary gonadotropes and directly at gonadal level. Various factors including availability and quality of food, photoperiod, temperature, social interaction, various stresses and some diseases modulate GnIH-GPR147 signaling. In this review, we have discussed expression and actions of GnIH and its orthologs in vertebrates. Special emphasis is given on the role of GnIH-GPR147 signaling pathway in the regulation of reproduction. We have also reviewed and discussed currently available literature on the participation of GnIH-GPR147 signaling pathway in the stress modulation of reproduction.
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Affiliation(s)
- Rahim Ullah
- Department of Endocrinology, Children Hospital of Zhejiang University, School of Medicine, Zhejiang University, Hangzhou, China; Laboratory of Reproductive Neuroendocrinology, Department of Animal Sciences, Faculty of Biological Sciences, Quaid-i-Azam University, Islamabad, Pakistan; Key Laboratory of Medical Neurobiology of Ministry of Health and Zhejiang Province, Department of Neurobiology, School of Medicine, Zhejiang University, Hangzhou 310058, PR China
| | - Yi Shen
- Key Laboratory of Medical Neurobiology of Ministry of Health and Zhejiang Province, Department of Neurobiology, School of Medicine, Zhejiang University, Hangzhou 310058, PR China
| | - Yu-Dong Zhou
- Key Laboratory of Medical Neurobiology of Ministry of Health and Zhejiang Province, Department of Neurobiology, School of Medicine, Zhejiang University, Hangzhou 310058, PR China
| | - Ke Huang
- Laboratory of Reproductive Neuroendocrinology, Department of Animal Sciences, Faculty of Biological Sciences, Quaid-i-Azam University, Islamabad, Pakistan; Laboratory of Reproductive Neuroendocrinology, Department of Animal Sciences, Faculty of Biological Sciences, Quaid-i-Azam University, Islamabad, Pakistan
| | - Jun-Fen Fu
- Department of Endocrinology, Children Hospital of Zhejiang University, School of Medicine, Zhejiang University, Hangzhou, China.
| | - Fazal Wahab
- Stem Cell Biology Unit, German Primate Center, Leibniz-Institute for Primate Research, Kellnerweg 4, 37077 Gottingen, Germany
| | - Muhammad Shahab
- Laboratory of Reproductive Neuroendocrinology, Department of Animal Sciences, Faculty of Biological Sciences, Quaid-i-Azam University, Islamabad, Pakistan.
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Dardente H, Lomet D, Robert V, Decourt C, Beltramo M, Pellicer-Rubio MT. Seasonal breeding in mammals: From basic science to applications and back. Theriogenology 2016; 86:324-32. [DOI: 10.1016/j.theriogenology.2016.04.045] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2015] [Revised: 02/02/2016] [Accepted: 03/14/2016] [Indexed: 12/29/2022]
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Nishiwaki-Ohkawa T, Yoshimura T. Molecular basis for regulating seasonal reproduction in vertebrates. J Endocrinol 2016; 229:R117-27. [PMID: 27068698 DOI: 10.1530/joe-16-0066] [Citation(s) in RCA: 81] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/24/2016] [Accepted: 04/11/2016] [Indexed: 12/31/2022]
Abstract
Animals that inhabit mid- to high-latitude regions exhibit various adaptive behaviors, such as migration, reproduction, molting and hibernation in response to seasonal cues. These adaptive behaviors are tightly regulated by seasonal changes in photoperiod, the relative day length vs night length. Recently, the regulatory pathway of seasonal reproduction has been elucidated using quail. In birds, deep brain photoreceptors receive and transmit light information to the pars tuberalis in the pituitary gland, which induces the secretion of thyroid-stimulating hormone. Thyroid-stimulating hormone locally activates thyroid hormone via induction of type 2 deiodinase in the mediobasal hypothalamus. Thyroid hormone then induces morphological changes in the terminals of neurons that express gonadotropin-releasing hormone and facilitates gonadotropin secretion from the pituitary gland. In mammals, light information is received by photoreceptors in the retina and neurally transmitted to the pineal gland, where it inhibits the synthesis and secretion of melatonin, which is crucial for seasonal reproduction. Importantly, the signaling pathway downstream of light detection and signaling is fully conserved between mammals and birds. In fish, the regulatory components of seasonal reproduction are integrated, from light detection to neuroendocrine output, in a fish-specific organ called the saccus vasculosus. Various physiological processes in humans are also influenced by seasonal environmental changes. The findings discussed herein may provide clues to addressing human diseases, such as seasonal affective disorder.
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Affiliation(s)
- Taeko Nishiwaki-Ohkawa
- Laboratory of Animal PhysiologyGraduate School of Bioagricultural Sciences, Nagoya University, Nagoya, Japan Institute of Transformative Bio-Molecules (WPI-ITbM)Nagoya University, Nagoya, Japan
| | - Takashi Yoshimura
- Laboratory of Animal PhysiologyGraduate School of Bioagricultural Sciences, Nagoya University, Nagoya, Japan Institute of Transformative Bio-Molecules (WPI-ITbM)Nagoya University, Nagoya, Japan Division of Seasonal BiologyNational Institute for Basic Biology, Okazaki, Japan Avian Bioscience Research CenterGraduate School of Bioagricultural Sciences, Nagoya University, Nagoya, Japan
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Banerjee S, Tsutsui K, Chaturvedi CM. Apoptosis-mediated testicular alteration in Japanese quail (Coturnix coturnix japonica) in response to temporal phase relation of serotonergic and dopaminergic oscillations. J Exp Biol 2016; 219:1476-87. [DOI: 10.1242/jeb.129155] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2015] [Accepted: 02/03/2016] [Indexed: 01/29/2023]
Abstract
ABSTRACT
Reproductive performance of many avian species, including Japanese quail, is reported to be modulated by specific temporal phase relation of serotonergic and dopaminergic oscillations. Accordingly, it has been shown that the serotonin precursor 5-HTP and the dopamine precursor l-DOPA given 8 h apart induce gonadal suppression and given 12 h apart lead to gonadal stimulation, while other temporal relationships were found to be ineffective. In the present study, we investigated the effects of 8- and 12-h phase relation of neural oscillations on testicular responses including expression of GnRH-I, GnIH, pro-apoptotic proteins (p53 and Bax), inactive and active executioner caspase-3, and the uncleaved DNA repair enzyme PARP-1. Testicular volume and mass decreased significantly in 8-h quail and increased in 12-h quail compared with controls. Expression of ir-GnIH, p53, Bax and active-caspase-3 increased and that of GnRH-I, pro-caspase-3 and uncleaved PARP-1 decreased in 8-h quail compared with controls. A TUNEL assay also confirmed testicular regression in these quail. Testes of 12-h quail exhibited significantly increased expression of GnRH-I, pro-caspase-3 and uncleaved PARP-1 compared with the control group. Our findings suggest that differential response of avian testes to 8- and 12-h phase relation of serotonergic and dopaminergic neural oscillations may be attributed to autocrine/paracrine action of GnIH expression, which is upregulated in regressed testes, leading to apoptotic changes, and downregulated in developed testes, causing apoptotic inhibition. It is concluded that specific phase relation of neural oscillations may modulate the local testicular GnRH-GnIH system and alter the apoptotic mechanism in quail testes. Moreover, these findings highlight the physiological effects of time-dependent drug delivery, including the specific time intervals between two drugs.
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Affiliation(s)
- Somanshu Banerjee
- Department of Zoology, Banaras Hindu University, Varanasi 221005, India
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Davies S, Lane S, Meddle SL, Tsutsui K, Deviche P. The ecological and physiological bases of variation in the phenology of gonad growth in an urban and desert songbird. Gen Comp Endocrinol 2016; 230-231:17-25. [PMID: 26972152 PMCID: PMC4890648 DOI: 10.1016/j.ygcen.2016.03.013] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/14/2015] [Revised: 03/08/2016] [Accepted: 03/09/2016] [Indexed: 01/09/2023]
Abstract
Birds often adjust to urban areas by advancing the timing (phenology) of vernal gonad growth. However, the ecological and physiological bases of this adjustment are unclear. We tested whether the habitat-related disparity in gonad growth phenology of male Abert's towhees, Melozone aberti, is due to greater food availability in urban areas of Phoenix, Arizona USA or, alternatively, a habitat-related difference in the phenology of key food types. To better understand the physiological mechanism underlying variation in gonad growth phenology, we compared the activity of the reproductive system at all levels of hypothalamo-pituitary-gonadal (HPG) axis. We found no habitat-associated difference in food availability (ground arthropod biomass), but, in contrast to the seasonal growth of leaves on desert trees, the leaf foliage of urban trees was already developed at the beginning of our study. Multiple estimates of energetic status did not significantly differ between the non-urban and urban towhees during three years that differed in the habitat-related disparity in gonad growth and winter precipitation levels. Thus, our results provide no support for the hypothesis that greater food abundance in urban areas of Phoenix drives the habitat-related disparity in gonad growth phenology in Abert's towhees. By contrast, they suggest that differences in the predictability and magnitude of change in food availability between urban and desert areas of Phoenix contribute to the observed habitat-related disparity in gonad growth. Endocrine responsiveness of the gonads may contribute to this phenomenon as desert - but not urban - towhees had a marked plasma testosterone response to GnRH challenge.
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Affiliation(s)
- Scott Davies
- School of Life Sciences, Arizona State University, Tempe, AZ 85287, USA.
| | - Samuel Lane
- School of Life Sciences, Arizona State University, Tempe, AZ 85287, USA
| | - Simone L Meddle
- The Roslin Institute & Royal (Dick) School of Veterinary Studies, University of Edinburgh, Roslin, Midlothian EH25 9PS, UK
| | - Kazuyoshi Tsutsui
- Laboratory of Integrative Brain Sciences, Department of Biology and Center for Medical Life Science, Waseda University, Tokyo 162-8480, Japan
| | - Pierre Deviche
- School of Life Sciences, Arizona State University, Tempe, AZ 85287, USA
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Paullada-Salmerón JA, Cowan M, Aliaga-Guerrero M, Morano F, Zanuy S, Muñoz-Cueto JA. Gonadotropin Inhibitory Hormone Down-Regulates the Brain-Pituitary Reproductive Axis of Male European Sea Bass (Dicentrarchus labrax). Biol Reprod 2016; 94:121. [PMID: 26984999 PMCID: PMC6322450 DOI: 10.1095/biolreprod.116.139022] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2016] [Accepted: 03/08/2016] [Indexed: 01/17/2023] Open
Abstract
Gonadotropin-inhibitory hormone (GnIH) inhibits gonadotropin synthesis and release from the pituitary of birds and mammals. However, the physiological role of orthologous GnIH peptides on the reproductive axis of fish is still uncertain, and their actions on the main neuroendocrine systems controlling reproduction (i.e., GnRHs, kisspeptins) have received little attention. In a recent study performed in the European sea bass, we cloned a cDNA encoding a precursor polypeptide that contained C-terminal MPMRFamide (sbGnIH-1) and MPQRFamide (sbGnIH-2) peptide sequences, developed a specific antiserum against sbGnIH-2, and characterized its central and pituitary GnIH projections in this species. In this study, we analyzed the effects of intracerebroventricular injection of sbGnIH-1 and sbGnIH-2 on brain and pituitary expression of reproductive hormone genes (gnrh1, gnrh2, gnrh3, kiss1, kiss2, gnih, lhbeta, fshbeta), and their receptors (gnrhr II-1a, gnrhr II-2b, kiss1r, kiss2r, and gnihr) as well as on plasma Fsh and Lh levels. In addition, we determined the effects of GnIH on pituitary somatotropin (Gh) expression. The results obtained revealed the inhibitory role of sbGnIH-2 on brain gnrh2, kiss1, kiss2, kiss1r, gnih, and gnihr transcripts and on pituitary fshbeta, lhbeta, gh, and gnrhr-II-1a expression, whereas sbGnIH-1 only down-regulated brain gnrh1 expression. However, at different doses, central administration of both sbGnIH-1 and sbGnIH-2 decreased Lh plasma levels. Our work represents the first study reporting the effects of centrally administered GnIH in fish and provides evidence of the differential actions of sbGnIH-1 and sbGnIH-2 on the reproductive axis of sea bass, the main inhibitory role being exerted by the sbGnIH-2 peptide.
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Affiliation(s)
- José A Paullada-Salmerón
- Department of Biology, Faculty of Environmental and Marine Sciences, University of Cádiz, Marine Campus of International Excellence (CEIMAR) and Agrifood Campus of International Excellence (ceiA3), Puerto Real, Spain INMAR-CACYTMAR Research Institutes, Puerto Real University Campus, Puerto Real, Spain
| | - Mairi Cowan
- Department of Biology, Faculty of Environmental and Marine Sciences, University of Cádiz, Marine Campus of International Excellence (CEIMAR) and Agrifood Campus of International Excellence (ceiA3), Puerto Real, Spain INMAR-CACYTMAR Research Institutes, Puerto Real University Campus, Puerto Real, Spain
| | - María Aliaga-Guerrero
- Department of Biology, Faculty of Environmental and Marine Sciences, University of Cádiz, Marine Campus of International Excellence (CEIMAR) and Agrifood Campus of International Excellence (ceiA3), Puerto Real, Spain INMAR-CACYTMAR Research Institutes, Puerto Real University Campus, Puerto Real, Spain
| | - Francesca Morano
- Department of Biology, Faculty of Environmental and Marine Sciences, University of Cádiz, Marine Campus of International Excellence (CEIMAR) and Agrifood Campus of International Excellence (ceiA3), Puerto Real, Spain INMAR-CACYTMAR Research Institutes, Puerto Real University Campus, Puerto Real, Spain
| | - Silvia Zanuy
- Institute of Aquaculture of Torre de la Sal, CSIC, Ribera de Cabanes, Castellón, Spain
| | - José A Muñoz-Cueto
- Department of Biology, Faculty of Environmental and Marine Sciences, University of Cádiz, Marine Campus of International Excellence (CEIMAR) and Agrifood Campus of International Excellence (ceiA3), Puerto Real, Spain INMAR-CACYTMAR Research Institutes, Puerto Real University Campus, Puerto Real, Spain
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42
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Banks R, Delibegovic M, Stevenson TJ. Photoperiod- and Triiodothyronine-dependent Regulation of Reproductive Neuropeptides, Proinflammatory Cytokines, and Peripheral Physiology in Siberian Hamsters (Phodopus sungorus). J Biol Rhythms 2016; 31:299-307. [DOI: 10.1177/0748730416637707] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Seasonal trade-offs in reproduction and immunity are ubiquitous in nature. The mechanisms that govern transitions across seasonal physiological states appear to involve reciprocal switches in the local synthesis of thyroid hormone. In long-day (LD) summer-like conditions, increased hypothalamic triiodothyronine (T3) stimulates gonadal development. Alternatively, short-day (SD) winter-like conditions increase peripheral leukocytes and enhance multiple aspects of immune function. These data indicate that the localized effects of T3 in the hypothalamus and leukocytes are photoperiod dependent. We tested the hypothesis that increased peripheral T3 in SD conditions would increase aspects of reproductive physiology and inhibit immune function, whereas T3 injections in LD conditions would facilitate aspects of immune function (i.e., leukocytes). In addition, we also examined whether T3 regulates hypothalamic neuropeptide expression as well as hypothalamic and splenic proinflammatory cytokine expression. Adult male Siberian hamsters were maintained in LD (15L:9D) or transferred to SD (9L:15D) for 8 weeks. A subset of LD and SD hamsters was treated daily with 5 µg T3 for 2 weeks. LD and SD controls were injected with saline. Daily T3 administration in SD hamsters (SD+T3) resulted in a rapid and substantial decrease in peripheral leukocyte concentrations and stimulated gonadal development. T3 treatment in LD (LD+T3) had no effect on testicular volumes but significantly increased leukocyte concentrations. Molecular analyses revealed that T3 stimulated interleukin 1β messenger RNA (mRNA) expression in the spleen and inhibited RFamide Related Peptide-3 mRNA expression in the hypothalamus. Moreover, there was a photoperiod-dependent decrease in splenic tumor necrosis factor–α mRNA expression. These findings reveal that T3 has tissue-specific and photoperiod-dependent regulation of seasonal rhythms in reproduction and immune function.
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Affiliation(s)
- Ruth Banks
- Institute for Biological and Environmental Sciences, University of Aberdeen, Aberdeen, UK
- Institute of Medical Sciences, University of Aberdeen, Aberdeen, UK
| | | | - Tyler J. Stevenson
- Institute for Biological and Environmental Sciences, University of Aberdeen, Aberdeen, UK
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Son YL, Ubuka T, Soga T, Yamamoto K, Bentley GE, Tsutsui K. Inhibitory action of gonadotropin‐inhibitory hormone on the signaling pathways induced by kisspeptin and vasoactive intestinal polypeptide in GnRH neuronal cell line, GT1–7. FASEB J 2016; 30:2198-210. [DOI: 10.1096/fj.201500055] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2015] [Accepted: 02/10/2016] [Indexed: 01/24/2023]
Affiliation(s)
- You Lee Son
- Laboratory of Integrative Brain SciencesDepartment of BiologyCenter for Medical Life ScienceWaseda UniversityTokyoJapan
| | - Takayoshi Ubuka
- Laboratory of Integrative Brain SciencesDepartment of BiologyCenter for Medical Life ScienceWaseda UniversityTokyoJapan
- Brain Research Institute, School of Medicine and Health Sciences, Monash UniversitySunwayMalaysia
| | - Tomoko Soga
- Brain Research Institute, School of Medicine and Health Sciences, Monash UniversitySunwayMalaysia
| | - Kazutoshi Yamamoto
- Laboratory of Integrative Brain SciencesDepartment of BiologyCenter for Medical Life ScienceWaseda UniversityTokyoJapan
| | - George E. Bentley
- Department of Integrative Biology and Helen Wills Neuroscience InstituteUniversity of CaliforniaBerkeleyBerkleyCaliforniaUSA
| | - Kazuyoshi Tsutsui
- Laboratory of Integrative Brain SciencesDepartment of BiologyCenter for Medical Life ScienceWaseda UniversityTokyoJapan
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Ukena K, Iwakoshi-Ukena E, Osugi T, Tsutsui K. Identification and localization of gonadotropin-inhibitory hormone (GnIH) orthologs in the hypothalamus of the red-eared slider turtle, Trachemys scripta elegans. Gen Comp Endocrinol 2016; 227:69-76. [PMID: 26130239 DOI: 10.1016/j.ygcen.2015.06.009] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/27/2015] [Revised: 06/10/2015] [Accepted: 06/15/2015] [Indexed: 01/27/2023]
Abstract
Gonadotropin-inhibitory hormone (GnIH) was discovered in 2000 as a novel hypothalamic neuropeptide that inhibited gonadotropin release in the Japanese quail. GnIH and its orthologs have a common C-terminal LPXRFamide (X=L or Q) motif, and have been identified in vertebrates from agnathans to humans, apart from reptiles. In the present study, we characterized a cDNA encoding GnIH orthologs in the brain of the red-eared slider turtle. The deduced precursor protein consisted of 205 amino-acid residues, encoding three putative peptide sequences that included the LPXRFamide motif at their C-termini. In addition, the precursor sequence was most similar to those of avian species. Immunoaffinity purification combined with mass spectrometry confirmed that three mature peptides were produced in the brain. In situ hybridization and immunohistochemistry showed that turtle GnIH-containing cells were restricted to the periventricular hypothalamic nucleus. Immunoreactive fibers were densely distributed in the median eminence. Thus, GnIH and related peptides may act on the pituitary to regulate pituitary hormone release in turtles as well as other vertebrates.
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Affiliation(s)
- Kazuyoshi Ukena
- Section of Behavioral Sciences, Graduate School of Integrated Arts and Sciences, Hiroshima University, Higashi-Hiroshima 739-8521, Japan.
| | - Eiko Iwakoshi-Ukena
- Section of Behavioral Sciences, Graduate School of Integrated Arts and Sciences, Hiroshima University, Higashi-Hiroshima 739-8521, Japan
| | - Tomohiro Osugi
- Laboratory of Integrative Brain Sciences, Department of Biology, Waseda University, Tokyo 162-8480, Japan
| | - Kazuyoshi Tsutsui
- Laboratory of Integrative Brain Sciences, Department of Biology, Waseda University, Tokyo 162-8480, Japan
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45
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Wingfield JC, Perfito N, Calisi R, Bentley G, Ubuka T, Mukai M, O'Brien S, Tsutsui K. Putting the brakes on reproduction: Implications for conservation, global climate change and biomedicine. Gen Comp Endocrinol 2016; 227:16-26. [PMID: 26474923 DOI: 10.1016/j.ygcen.2015.10.007] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/28/2015] [Accepted: 10/08/2015] [Indexed: 02/07/2023]
Abstract
Seasonal breeding is widespread in vertebrates and involves sequential development of the gonads, onset of breeding activities (e.g. cycling in females) and then termination resulting in regression of the reproductive system. Whereas males generally show complete spermatogenesis prior to and after onset of breeding, females of many vertebrate species show only partial ovarian development and may delay onset of cycling (e.g. estrous), yolk deposition or germinal vesicle breakdown until conditions conducive for ovulation and onset of breeding are favorable. Regulation of this "brake" on the onset of breeding remains relatively unknown, but could have profound implications for conservation efforts and for "mismatches" of breeding in relation to global climate change. Using avian models it is proposed that a brain peptide, gonadotropin-inhibitory hormone (GnIH), may be the brake to prevent onset of breeding in females. Evidence to date suggests that although GnIH may be involved in the regulation of gonadal development and regression, it plays more regulatory roles in the process of final ovarian development leading to ovulation, transitions from sexual to parental behavior and suppression of reproductive function by environmental stress. Accumulating experimental evidence strongly suggests that GnIH inhibits actions of gonadotropin-releasing hormones on behavior (central effects), gonadotropin secretion (central and hypophysiotropic effects), and has direct actions in the gonad to inhibit steroidogenesis. Thus, actual onset of breeding activities leading to ovulation may involve environmental cues releasing an inhibition (brake) on the hypothalamo-pituitary-gonad axis.
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Affiliation(s)
- John C Wingfield
- Department of Neurobiology, Physiology and Behavior, University of California, One Shields Avenue, Davis, CA 95616, USA.
| | - Nicole Perfito
- Department of Integrative Biology, University of California, Berkeley, CA 94720, USA
| | - Rebecca Calisi
- Department of Biology, Barnard College, Columbia University, New York, NY 10027, USA
| | - George Bentley
- Department of Integrative Biology, University of California, Berkeley, CA 94720, USA
| | - T Ubuka
- Department of Biology, Waseda University, Shinjuku-ku, Tokyo 162-8480, Japan
| | - M Mukai
- Department of Food Science, College of Agriculture and Life Sciences, Cornell University, Ithaca, NY 14853, USA
| | - Sara O'Brien
- Department of Biology, Radford University, Radford, VA 24142, USA
| | - K Tsutsui
- Department of Biology, Waseda University, Shinjuku-ku, Tokyo 162-8480, Japan
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Tsutsui K, Ubuka T. GnIH Control of Feeding and Reproductive Behaviors. Front Endocrinol (Lausanne) 2016; 7:170. [PMID: 28082949 PMCID: PMC5186799 DOI: 10.3389/fendo.2016.00170] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/25/2016] [Accepted: 12/16/2016] [Indexed: 11/13/2022] Open
Abstract
In 2000, Tsutsui and colleagues discovered a neuropeptide gonadotropin-inhibitory hormone (GnIH) that inhibits gonadotropin release in birds. Subsequently, extensive studies during the last 15 years have demonstrated that GnIH is a key neurohormone that regulates reproduction in vertebrates, acting in the brain and on the pituitary to modulate reproduction and reproductive behavior. On the other hand, deprivation of food and other metabolic challenges inhibit the reproductive axis as well as sexual motivation. Interestingly, recent studies have further indicated that GnIH controls feeding behavior in vertebrates, such as in birds and mammals. This review summarizes the discovery of GnIH and its conservation in vertebrates and the neuroendocrine control of feeding behavior and reproductive behavior by GnIH.
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Affiliation(s)
- Kazuyoshi Tsutsui
- Laboratory of Integrative Brain Sciences, Department of Biology and Center for Medical Life Science, Waseda University, Tokyo, Japan
- *Correspondence: Kazuyoshi Tsutsui,
| | - Takayoshi Ubuka
- Laboratory of Integrative Brain Sciences, Department of Biology and Center for Medical Life Science, Waseda University, Tokyo, Japan
- Jeffrey Cheah School of Medicine and Health Sciences, Brain Research Institute Monash Sunway, Monash University Malaysia, Bandar Sunway, Malaysia
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Maitra SK, Hasan KN. The Role of Melatonin as a Hormone and an Antioxidant in the Control of Fish Reproduction. Front Endocrinol (Lausanne) 2016; 7:38. [PMID: 27199895 PMCID: PMC4854901 DOI: 10.3389/fendo.2016.00038] [Citation(s) in RCA: 42] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/02/2016] [Accepted: 04/21/2016] [Indexed: 11/13/2022] Open
Abstract
Reproduction in most fish is seasonal or periodic, and the spawning occurs in an appropriate season to ensure maximum survival of the offspring. The sequence of reproductive events in an annual cycle is largely under the control of a species-specific endogenous timing system, which essentially relies on a well-equipped physiological response mechanism to changing environmental cues. The duration of solar light or photoperiod is one of the most predictable environmental signals used by a large number of animals including fish to coordinate their seasonal breeding. In vertebrates, the pineal gland is the major photoneuroendocrine part of the brain that rhythmically synthesizes and releases melatonin (N-acetyl-5-methoxytryptamine) into the circulation in synchronization with the environmental light-dark cycle. Past few decades witnessed an enormous progress in understanding the mechanisms by which melatonin regulates seasonal reproduction in fish and in other vertebrates. Most studies emphasized hormonal actions of melatonin through its high-affinity, pertussis toxin-sensitive G-protein (guanine nucleotide-binding protein)-coupled receptors on the hypothalamus-pituitary-gonad (HPG) axis of fish. However, the discovery that melatonin due to its lipophilic nature can easily cross the plasma membrane of all cells and may act as a potent scavenger of free radicals and stimulant of different antioxidants added a new dimension to the idea explaining mechanisms of melatonin actions in the regulation of ovarian functions. The basic concept on the actions of melatonin as an antioxidant emerged from mammalian studies. Recently, however, some new studies clearly suggested that melatonin, apart from playing the role of a hormone, may also be associated with the reduction in oxidative stress to augment ovarian functions during spawning. This review thus aims to bring together the current knowledge on the role of melatonin as a hormone as well as an antioxidant in the control of fish reproduction and shape the current working hypotheses supported by recent findings obtained in carp or based on knowledge gathered in mammalian and avian species. In essence, this review highlights potential actions of melatonin as a hormone in determining temporal pattern of spawning and as an antioxidant in regulating oocyte maturation at the downstream of HPG axis in fish.
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Affiliation(s)
- Saumen Kumar Maitra
- Department of Zoology, Visva-Bharati University, Santiniketan, India
- *Correspondence: Saumen Kumar Maitra,
| | - Kazi Nurul Hasan
- Department of Zoology, Visva-Bharati University, Santiniketan, India
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Abstract
The endocrine hypothalamus constitutes those cells which project to the median eminence and secrete neurohormones into the hypophysial portal blood to act on cells of the anterior pituitary gland. The entire endocrine system is controlled by these peptides. In turn, the hypothalamic neuroendocrine cells are regulated by feedback signals from the endocrine glands and other circulating factors. The neuroendocrine cells are found in specific regions of the hypothalamus and are regulated by afferents from higher brain centers. Integrated function is clearly complex and the networks between and amongst the neuroendocrine cells allows fine control to achieve homeostasis. The entry of hormones and other factors into the brain, either via the cerebrospinal fluid or through fenestrated capillaries (in the basal hypothalamus) is important because it influences the extent to which feedback regulation may be imposed. Recent evidence of the passage of factors from the pars tuberalis and the median eminence casts a new layer in our understanding of neuroendocrine regulation. The function of neuroendocrine cells and the means by which pulsatile secretion is achieved is best understood for the close relationship between gonadotropin releasing hormone and luteinizing hormone, which is reviewed in detail. The secretion of other neurohormones is less rigid, so the relationship between hypothalamic secretion and the relevant pituitary hormones is more complex.
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Affiliation(s)
- I J Clarke
- Monash University, Department of Physiology, Clayton, Australia
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Majumdar G, Trivedi AK, Gupta NJ, Kumar V. Circadian synchronization determines critical day length for seasonal responses. Physiol Behav 2015; 147:282-90. [DOI: 10.1016/j.physbeh.2015.05.005] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2015] [Revised: 05/02/2015] [Accepted: 05/04/2015] [Indexed: 10/23/2022]
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Amorin N, Calisi RM. Measurements of Neuronal Soma Size and Estimated Peptide Concentrations in Addition to Cell Abundance Offer a Higher Resolution of Seasonal and Reproductive Influences of GnRH-I and GnIH in European Starlings. Integr Comp Biol 2015; 55:332-42. [DOI: 10.1093/icb/icv063] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
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