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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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Singh P, Anjum S, Srivastava RK, Tsutsui K, Krishna A. Central and peripheral neuropeptide RFRP-3: A bridge linking reproduction, nutrition, and stress response. Front Neuroendocrinol 2022; 65:100979. [PMID: 35122778 DOI: 10.1016/j.yfrne.2022.100979] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/05/2021] [Revised: 11/30/2021] [Accepted: 01/06/2022] [Indexed: 02/06/2023]
Abstract
This article is an amalgamation of the current status of RFRP-3 (GnIH) in reproduction and its association with the nutrition and stress-mediated changes in the reproductive activities. GnIH has been demonstrated in the hypothalamus of all the vertebrates studied so far and is a well-known inhibitor of GnRH mediated reproduction. The RFRP-3 neurons interact with the other hypothalamic neurons and the hormonal signals from peripheral organs for coordinating the nutritional, stress, and environmental associated changes to regulate reproduction. RFRP-3 has also been shown to regulate puberty, reproductive cyclicity and senescence depending upon the nutritional status. A favourable nutritional status and the environmental cues which are permissive for the successful breeding and pregnancy outcome keep RFRP-3 level low, whereas unfavourable nutritional status and stressful conditions increase the expression of RFRP-3 which impairs the reproduction. Still our knowledge about RFRP-3 is incomplete regarding its therapeutic application for nutritional or stress-related reproductive disorders.
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Affiliation(s)
- Padmasana Singh
- Department of Zoology, Indira Gandhi National Tribal University, Amarkantak, Anuppur 484886, MP, India
| | - Shabana Anjum
- Department of Chemical Engineering, American University of Sharjah, Sharjah 26666, United Arab Emirates
| | - Raj Kamal Srivastava
- Department of Zoology, Indira Gandhi National Tribal University, Amarkantak, Anuppur 484886, MP, India
| | - Kazuyoshi Tsutsui
- Department of Biology and Center for Medical Life Science, Waseda University, Kagamiyama 1-7-1, Higashi-Hiroshima University 739-8521, Japan
| | - Amitabh Krishna
- Department of Zoology, Banaras Hindu University, Varanasi 221005, UP, India.
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Comparative insights of the neuroanatomical distribution of the gonadotropin-inhibitory hormone (GnIH) in fish and amphibians. Front Neuroendocrinol 2022; 65:100991. [PMID: 35227766 DOI: 10.1016/j.yfrne.2022.100991] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/23/2021] [Revised: 12/17/2021] [Accepted: 01/26/2022] [Indexed: 11/21/2022]
Abstract
This paper intends to apprise the reader regarding the existing knowledge on the neuroanatomical distribution of GnIH-like peptides in in fish and amphibians in both the adult stage and during ontogenesis. The neuroanatomical distribution of GnIH-like neuropeptides appears quite different in the studied species, irrespective of the evolutionary closeness. The topology of the olfactory bulbs can affect the distribution of neurons producing the GnIH-like peptides, with a tendency to show a more extended distribution into the brains with pedunculate olfactory bulbs. Therefore, the variability of the GnIH-like system could also reflect specific adaptations rather than evolutionary patterns. The onset of GnIH expression was detected very early during development suggesting its precocious roles, and the neuroanatomical distribution of GnIH-like elements showed a generally increasing trend. This review highlights some critical technical aspects and the need to increase the number of species to be studied to obtain a complete neuroanatomical picture of the GnIH-like system.
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Neuropeptidergic control of neurosteroids biosynthesis. Front Neuroendocrinol 2022; 65:100976. [PMID: 34999057 DOI: 10.1016/j.yfrne.2021.100976] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/21/2021] [Revised: 12/12/2021] [Accepted: 12/22/2021] [Indexed: 01/14/2023]
Abstract
Neurosteroids are steroids synthesized within the central nervous system either from cholesterol or by metabolic reactions of circulating steroid hormone precursors. It has been suggested that neurosteroids exert pleiotropic activities within the central nervous system, such as organization and activation of the central nervous system and behavioral regulation. It is also increasingly becoming clear that neuropeptides exert pleiotropic activities within the central nervous system, such as modulation of neuronal functions and regulation of behavior, besides traditional neuroendocrinological functions. It was hypothesized that some of the physiological functions of neuropeptides acting within the central nervous system may be through the regulation of neurosteroids biosynthesis. Various neuropeptides reviewed in this study possibly regulate neurosteroids biosynthesis by controlling the activities of enzymes that catalyze the production of neurosteroids. It is now required to thoroughly investigate the neuropeptidergic control mechanisms of neurosteroids biosynthesis to characterize the physiological significance of this new neuroendocrinological phenomenon.
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Characterization and Distribution of Kisspeptins, Kisspeptin Receptors, GnIH, and GnRH1 in the Brain of the Protogynous Bluehead Wrasse (Thalassoma bifasciatum). J Chem Neuroanat 2022; 121:102087. [DOI: 10.1016/j.jchemneu.2022.102087] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2021] [Revised: 02/14/2022] [Accepted: 03/08/2022] [Indexed: 11/18/2022]
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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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8
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Alonge MM, Greville LJS, Faure PA, Bentley GE. Immunoreactive distribution of gonadotropin-inhibitory hormone precursor, RFRP, in a temperate bat species (Eptesicus fuscus). J Comp Neurol 2021; 530:1459-1469. [PMID: 34957555 DOI: 10.1002/cne.25291] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2021] [Revised: 11/17/2021] [Accepted: 12/07/2021] [Indexed: 11/08/2022]
Abstract
Gonadotropin-inhibitory hormone (GnIH, also known RFRP-3 in mammals) is an important regulator of the hypothalamic-pituitary-gonadal (HPG) axis and downstream reproductive physiology. Substantial species differences exist in the localization of cell bodies producing RFRP-3 and patterns of fiber immunoreactivity in the brain, raising the question of functional differences. Many temperate bat species exhibit unusual annual reproductive patterns. Male bats upregulate spermatogenesis in late spring which is asynchronous with periods of mating in the fall, while females have the physiological capacity to delay their reproductive investment over winter via sperm storage or delayed ovulation/fertilization. Neuroendocrine mechanisms regulating reproductive timing in male and female bats are not well-studied. We provide the first description of RFRP - precursor peptide of gonadotropin-inhibitory hormone - expression and localization in the brain of any bat using a widespread temperate species (Eptesicus fuscus, big brown bat) as a model. RFRP mRNA expression was detected in the hypothalamus, testes, and ovaries of big brown bats. Cellular RFRP-immunoreactivity was observed within the PVN, DMH, arcuate nucleus (Arc) and median eminence (ME). As in other vertebrates, RFRP fiber immunoreactivity was widespread, with greatest density observed in the hypothalamus, POA, ARC, ME, midbrain, and thalamic nuclei. Putative interactions between RFRP-ir fibers and gonadotropin-releasing hormone cell bodies were observed in 16% of GnRH-ir cells, suggesting direct regulation of GnRH via RFRP signaling. This characterization of RFRP distribution contributes to deeper understanding of bat neuroendocrinology which serves as foundation for manipulative approaches examining changes in reproductive neuropeptide signaling in response to environmental and physiological challenges within, and among, bat species. This article is protected by copyright. All rights reserved.
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Affiliation(s)
- Mattina M Alonge
- University of California Berkeley, Department of Integrative Biology and Helen Wills Neuroscience Institute, Berkeley, California, USA
| | - Lucas J S Greville
- McMaster University, Department of Psychology, Neuroscience & Behavior, Hamilton, Ontario, Canada
| | - Paul A Faure
- McMaster University, Department of Psychology, Neuroscience & Behavior, Hamilton, Ontario, Canada
| | - George E Bentley
- University of California Berkeley, Department of Integrative Biology and Helen Wills Neuroscience Institute, Berkeley, California, USA
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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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Tan YG, Xu XL, Cao HY, Mao HG, Yin ZZ. RFamide-related peptides' gene expression, polymorphism, and their association with reproductive traits in chickens. Poult Sci 2021; 100:488-495. [PMID: 33518101 PMCID: PMC7858160 DOI: 10.1016/j.psj.2020.11.024] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2020] [Revised: 11/05/2020] [Accepted: 11/09/2020] [Indexed: 12/18/2022] Open
Abstract
RFamide-related peptides (RFRP) are synthesized by the hypothalamus and have a regulatory role in gonad development. The goal of this study was to investigate the association between SNP of the RFRP gene and the reproductive traits and hormone levels of Zhenning yellow chickens. The mRNA expression levels were detected based on different tissues, ages, and genotypes. Eleven mutation sites were detected in the RFRP gene, 4 of which were significantly related to reproductive traits and hormone levels. Association analysis revealed that A276G was associated with egg production at 300 d of age (EP300) and amount of prehierarchical follicles (P < 0.05). G1396A was associated with egg weight at 300 d of age and luteinizing hormone (LH) and prolactin levels (P < 0.05). G1694A showed significant associations with fertilization rate and LH levels (P < 0.05), and A2659G was associated with EP300 (P < 0.05). The results of expression analysis showed that the RFRP mRNA expression levels in the hypothalamus were higher than those in other tissues (P < 0.01). The expression in immature individuals was higher than that in mature ones (P < 0.01). There were also differences in mRNA expression levels between different genotypes (P < 0.05). In summary, the results of this study might provide potential markers and a theoretical basis for the improvement of chicken reproductive traits.
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Affiliation(s)
- Y G Tan
- Animal Science College, Zhejiang University, Zijingang Campus, Hangzhou 310058, China
| | - X L Xu
- Animal Science College, Zhejiang University, Zijingang Campus, Hangzhou 310058, China
| | - H Y Cao
- Animal Science College, Zhejiang University, Zijingang Campus, Hangzhou 310058, China
| | - H G Mao
- Animal Science College, Zhejiang University, Zijingang Campus, Hangzhou 310058, China
| | - Z Z Yin
- Animal Science College, Zhejiang University, Zijingang Campus, Hangzhou 310058, China.
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Bédécarrats GY, Hanlon C, Tsutsui K. Gonadotropin Inhibitory Hormone and Its Receptor: Potential Key to the Integration and Coordination of Metabolic Status and Reproduction. Front Endocrinol (Lausanne) 2021; 12:781543. [PMID: 35095760 PMCID: PMC8792613 DOI: 10.3389/fendo.2021.781543] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/22/2021] [Accepted: 12/02/2021] [Indexed: 12/18/2022] Open
Abstract
Since its discovery as a novel gonadotropin inhibitory peptide in 2000, the central and peripheral roles played by gonadotropin-inhibiting hormone (GnIH) have been significantly expanded. This is highlighted by the wide distribution of its receptor (GnIH-R) within the brain and throughout multiple peripheral organs and tissues. Furthermore, as GnIH is part of the wider RF-amide peptides family, many orthologues have been characterized across vertebrate species, and due to the promiscuity between ligands and receptors within this family, confusion over the nomenclature and function has arisen. In this review, we intend to first clarify the nomenclature, prevalence, and distribution of the GnIH-Rs, and by reviewing specific localization and ligand availability, we propose an integrative role for GnIH in the coordination of reproductive and metabolic processes. Specifically, we propose that GnIH participates in the central regulation of feed intake while modulating the impact of thyroid hormones and the stress axis to allow active reproduction to proceed depending on the availability of resources. Furthermore, beyond the central nervous system, we also propose a peripheral role for GnIH in the control of glucose and lipid metabolism at the level of the liver, pancreas, and adipose tissue. Taken together, evidence from the literature strongly suggests that, in fact, the inhibitory effect of GnIH on the reproductive axis is based on the integration of environmental cues and internal metabolic status.
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Affiliation(s)
- Grégoy Y. Bédécarrats
- Department of Animal Biosciences, University of Guelph, Guelph, ON, Canada
- *Correspondence: Grégoy Y. Bédécarrats,
| | - Charlene Hanlon
- Department of Animal Biosciences, University of Guelph, Guelph, ON, Canada
| | - Kazuyoshi Tsutsui
- Graduate School of Integrated Sciences for Life, Hiroshima University, Higashihiroshima, Japan
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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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Poissenot K, Anger K, Constantin P, Cornilleau F, Lomet D, Tsutsui K, Dardente H, Calandreau L, Beltramo M. Brain mapping of the gonadotropin-inhibitory hormone-related peptide 2 with a novel antibody suggests a connection with emotional reactivity in the Japanese quail (Coturnix japonica, Temminck & Schlegel, 1849). J Comp Neurol 2019; 527:1872-1884. [PMID: 30734308 DOI: 10.1002/cne.24659] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2018] [Revised: 01/22/2019] [Accepted: 01/25/2019] [Indexed: 12/23/2022]
Abstract
Gonadotropin-inhibitory hormone (GnIH) is a neuropeptide first discovered in the quail brain that is involved in the control of reproductive physiology and behaviors, and stress response. GnIH gene encodes a second peptide, GnIH-related peptide-2 (RP2), the distribution and function of which remain unknown. We therefore studied GnIH-RP2 distribution by immunohistochemistry using a novel antibody capable of discriminating between GnIH and GnIH-RP2. The overall distribution of GnIH-RP2 is similar to that of GnIH. The vast majority of labeled neurons is located in the paraventricular nucleus (PVN) of the hypothalamus. Labeling of fibers is conspicuous in the diencephalon, but present also in the mesencephalon and telencephalon. Several regions involved in the control of reproduction and stress response (the PVN, septum, bed nucleus of the stria terminalis and nucleus commissura pallii) showed a dense network of immunolabeled fibers. To investigate the potential function of GnIH-RP2 we compared its expression in two quail lines genetically selected for divergence in their emotional reactivity. A quantitative analysis in the above-mentioned brain regions showed that the density of fibers was similar in the two lines. However, the number of GnIH-RP2 labeled neurons was higher in the median portion of the PVN in birds with higher emotional reactivity. These results point to a possible involvement of GnRH-RP2 in modulating stress response and/or emotional reactivity.
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Affiliation(s)
- Kevin Poissenot
- INRA, UMR85 Physiologie de la Reproduction et des Comportements; CNRS, UMR7247, Université de Tours, IFCE, Nouzilly, France
| | - Karine Anger
- INRA, UMR85 Physiologie de la Reproduction et des Comportements; CNRS, UMR7247, Université de Tours, IFCE, Nouzilly, France
| | - Paul Constantin
- INRA, UMR85 Physiologie de la Reproduction et des Comportements; CNRS, UMR7247, Université de Tours, IFCE, Nouzilly, France
| | - Fabien Cornilleau
- INRA, UMR85 Physiologie de la Reproduction et des Comportements; CNRS, UMR7247, Université de Tours, IFCE, Nouzilly, France
| | - Didier Lomet
- INRA, UMR85 Physiologie de la Reproduction et des Comportements; CNRS, UMR7247, Université de Tours, IFCE, Nouzilly, France
| | - Kazuyoshi Tsutsui
- Laboratory of Integrative Brain Sciences, Department of Biology and Center for Medical Life Science, Waseda University, Tokyo, Japan
| | - Hugues Dardente
- INRA, UMR85 Physiologie de la Reproduction et des Comportements; CNRS, UMR7247, Université de Tours, IFCE, Nouzilly, France
| | - Ludovic Calandreau
- INRA, UMR85 Physiologie de la Reproduction et des Comportements; CNRS, UMR7247, Université de Tours, IFCE, Nouzilly, France
| | - Massimiliano Beltramo
- INRA, UMR85 Physiologie de la Reproduction et des Comportements; CNRS, UMR7247, Université de Tours, IFCE, Nouzilly, France
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16
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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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17
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Wu Y, Zhang Y, Hou Z, Fan G, Pi J, Sun S, Chen J, Liu H, Du X, Shen J, Hu G, Chen W, Pan A, Yin P, Chen X, Pu Y, Zhang H, Liang Z, Jian J, Zhang H, Wu B, Sun J, Chen J, Tao H, Yang T, Xiao H, Yang H, Zheng C, Bai M, Fang X, Burt DW, Wang W, Li Q, Xu X, Li C, Yang H, Wang J, Yang N, Liu X, Du J. Population genomic data reveal genes related to important traits of quail. Gigascience 2018; 7:4995262. [PMID: 29762663 PMCID: PMC5961004 DOI: 10.1093/gigascience/giy049] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2017] [Accepted: 04/27/2018] [Indexed: 12/18/2022] Open
Abstract
Background Japanese quail (Coturnix japonica), a recently domesticated poultry species, is important not only as an agricultural product, but also as a model bird species for genetic research. However, most of the biological questions concerning genomics, phylogenetics, and genetics of some important economic traits have not been answered. It is thus necessary to complete a high-quality genome sequence as well as a series of comparative genomics, evolution, and functional studies. Results Here, we present a quail genome assembly spanning 1.04 Gb with 86.63% of sequences anchored to 30 chromosomes (28 autosomes and 2 sex chromosomes Z/W). Our genomic data have resolved the long-term debate of phylogeny among Perdicinae (Japanese quail), Meleagridinae (turkey), and Phasianinae (chicken). Comparative genomics and functional genomic data found that four candidate genes involved in early maturation had experienced positive selection, and one of them encodes follicle stimulating hormone beta (FSHβ), which is correlated with different FSHβ levels in quail and chicken. We re-sequenced 31 quails (10 wild, 11 egg-type, and 10 meat-type) and identified 18 and 26 candidate selective sweep regions in the egg-type and meat-type lines, respectively. That only one of them is shared between egg-type and meat-type lines suggests that they were subject to an independent selection. We also detected a haplotype on chromosome Z, which was closely linked with maroon/yellow plumage in quail using population resequencing and a genome-wide association study. This haplotype block will be useful for quail breeding programs. Conclusions This study provided a high-quality quail reference genome, identified quail-specific genes, and resolved quail phylogeny. We have identified genes related to quail early maturation and a marker for plumage color, which is significant for quail breeding. These results will facilitate biological discovery in quails and help us elucidate the evolutionary processes within the Phasianidae family.
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Affiliation(s)
- Yan Wu
- Institute of Animal Husbandry and Veterinary, Hubei Academy of Agricultural Science, Wuhan 430064, China.,Key Laboratory of Animal Embryo Engineering and Molecular Breeding of Hubei Province,Wuhan 430064, China.,Hubei Innovation Center of Agricultural Science and Technology, Wuhan, Hubei, 430064, China
| | - Yaolei Zhang
- BGI-Shenzhen, Shenzhen 518083, China.,BGI-Qingdao, BGI-Shenzhen, Qingdao, 266555, China.,China National GeneBank-Shenzhen, BGI-Shenzhen, Shenzhen 518083, China
| | - Zhuocheng Hou
- National Engineering Laboratory for Animal Breeding and MOA Key Laboratory of Animal Genetics and Breeding, China; Agricultural University, Beijing 100193, China
| | - Guangyi Fan
- BGI-Shenzhen, Shenzhen 518083, China.,BGI-Qingdao, BGI-Shenzhen, Qingdao, 266555, China.,State Key Laboratory of Quality Research in Chinese Medicine and Institute of Chinese Medical Sciences, Macao, China.,China National GeneBank-Shenzhen, BGI-Shenzhen, Shenzhen 518083, China
| | - Jinsong Pi
- Institute of Animal Husbandry and Veterinary, Hubei Academy of Agricultural Science, Wuhan 430064, China
| | - Shuai Sun
- BGI-Qingdao, BGI-Shenzhen, Qingdao, 266555, China
| | - Jiang Chen
- BGI-Shenzhen, Shenzhen 518083, China.,China National GeneBank-Shenzhen, BGI-Shenzhen, Shenzhen 518083, China
| | - Huaqiao Liu
- Hubei Shendan Healthy Food Co., Ltd., Wuhan 430206, China
| | - Xiao Du
- BGI-Qingdao, BGI-Shenzhen, Qingdao, 266555, China
| | - Jie Shen
- Institute of Animal Husbandry and Veterinary, Hubei Academy of Agricultural Science, Wuhan 430064, China
| | - Gang Hu
- BGI-Qingdao, BGI-Shenzhen, Qingdao, 266555, China
| | | | - Ailuan Pan
- Institute of Animal Husbandry and Veterinary, Hubei Academy of Agricultural Science, Wuhan 430064, China
| | - Pingping Yin
- BGI-Qingdao, BGI-Shenzhen, Qingdao, 266555, China
| | | | - Yuejin Pu
- Institute of Animal Husbandry and Veterinary, Hubei Academy of Agricultural Science, Wuhan 430064, China
| | - He Zhang
- BGI-Shenzhen, Shenzhen 518083, China
| | - Zhenhua Liang
- Institute of Animal Husbandry and Veterinary, Hubei Academy of Agricultural Science, Wuhan 430064, China
| | | | - Hao Zhang
- Institute of Animal Husbandry and Veterinary, Hubei Academy of Agricultural Science, Wuhan 430064, China
| | - Bin Wu
- BGI-Shenzhen, Shenzhen 518083, China
| | - Jing Sun
- Institute of Animal Husbandry and Veterinary, Hubei Academy of Agricultural Science, Wuhan 430064, China
| | | | - Hu Tao
- Institute of Animal Husbandry and Veterinary, Hubei Academy of Agricultural Science, Wuhan 430064, China
| | - Ting Yang
- BGI-Shenzhen, Shenzhen 518083, China
| | - Hongwei Xiao
- Institute of Animal Husbandry and Veterinary, Hubei Academy of Agricultural Science, Wuhan 430064, China
| | - Huan Yang
- BGI-Shenzhen, Shenzhen 518083, China
| | - Chuanwei Zheng
- Institute of Animal Husbandry and Veterinary, Hubei Academy of Agricultural Science, Wuhan 430064, China
| | | | | | - David W Burt
- The Roslin Institute and Royal (Dick) School of Veterinary Studies, University of Edinburgh, Midlothian EH25 9RG, UK
| | - Wen Wang
- Kunming Institute of Zoology, Chinese Academy of Sciences (CAS), Kunming, China
| | - Qingyi Li
- BGI-Qingdao, BGI-Shenzhen, Qingdao, 266555, China
| | - Xun Xu
- BGI-Shenzhen, Shenzhen 518083, China.,China National GeneBank-Shenzhen, BGI-Shenzhen, Shenzhen 518083, China
| | - Chengfeng Li
- BGI-Qingdao, BGI-Shenzhen, Qingdao, 266555, China
| | - Huanming Yang
- BGI-Shenzhen, Shenzhen 518083, China.,James D. Watson Institute of Genome Sciences, Hangzhou 310058, China
| | - Jian Wang
- BGI-Shenzhen, Shenzhen 518083, China.,James D. Watson Institute of Genome Sciences, Hangzhou 310058, China
| | - Ning Yang
- National Engineering Laboratory for Animal Breeding and MOA Key Laboratory of Animal Genetics and Breeding, China; Agricultural University, Beijing 100193, China
| | - Xin Liu
- BGI-Shenzhen, Shenzhen 518083, China.,China National GeneBank-Shenzhen, BGI-Shenzhen, Shenzhen 518083, China
| | - Jinping Du
- Institute of Animal Husbandry and Veterinary, Hubei Academy of Agricultural Science, Wuhan 430064, China
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18
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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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19
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Ubuka T, Tsutsui K. Comparative and Evolutionary Aspects of Gonadotropin-Inhibitory Hormone and FMRFamide-Like Peptide Systems. Front Neurosci 2018; 12:747. [PMID: 30405335 PMCID: PMC6200920 DOI: 10.3389/fnins.2018.00747] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2018] [Accepted: 09/28/2018] [Indexed: 11/13/2022] Open
Abstract
Gonadotropin-inhibitory hormone (GnIH) is a hypothalamic neuropeptide that was found in the brain of Japanese quail when investigating the existence of RFamide peptides in birds. GnIH was named because it decreased gonadotropin release from cultured anterior pituitary, which was located in the hypothalamo-hypophysial system. GnIH and GnIH precursor gene related peptides have a characteristic C-terminal LPXRFamide (X = L or Q) motif that is conserved in jawed vertebrates. Orthologous peptides to GnIH are also named RFamide related peptide or LPXRFamide peptide from their structure. A G-protein coupled receptor GPR147 is the primary receptor for GnIH. Similarity-based clustering of neuropeptide precursors in metazoan species indicates that GnIH precursor of vertebrates is evolutionarily related to FMRFamide precursor of mollusk and nematode. FMRFamide peptide is the first RFamide peptide that was identified from the ganglia of the venus clam. In order to infer the evolutionary history of the GnIH-GnIH receptor system we investigate the structural similarities between GnIH and its receptor and well-studied nematode Caenorhabditis elegans (C. elegans) FMRFamide-like peptides (FLPs) and their receptors. We also compare the functions of FLPs of nematode with GnIH of chordates. A multiple sequence alignment and phylogenetic analyses of GnIH, neuropeptide FF (NPFF), a paralogous peptide of GnIH, and FLP precursors have shown that GnIH and NPFF precursors belong to different clades and some FLP precursors have structural similarities to either precursor. The peptide coding regions of FLP precursors in the same clade align well with those of GnIH or NPFF precursors. Alignment of GnIH (LPXRFa) peptides of chordates and FLPs of C. elegans grouped the peptides into five groups according to the last C-terminal amino acid sequences, which were MRFa, LRFa, VRFa, IRFa, and PQRFa. Phylogenetic analysis of receptors suggested that GPR147 has evolutionary relationships with FLP receptors, which regulate reproduction, aggression, locomotion, and feeding. GnIH and some FLPs mediate the effect of stress on reproduction and behavior, which may also be a conserved property of these peptide systems. Future studies are needed to investigate the mechanism of how neuropeptide precursor genes are mutated to evolve new neuropeptides and their inheritance.
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Affiliation(s)
- Takayoshi Ubuka
- Laboratory of Integrative Brain Sciences, Department of Biology and Center for Medical Life Science, Waseda University, Shinjuku, Japan
| | - Kazuyoshi Tsutsui
- Laboratory of Integrative Brain Sciences, Department of Biology and Center for Medical Life Science, Waseda University, Shinjuku, Japan
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20
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Kaprara A, Huhtaniemi IT. The hypothalamus-pituitary-gonad axis: Tales of mice and men. Metabolism 2018; 86:3-17. [PMID: 29223677 DOI: 10.1016/j.metabol.2017.11.018] [Citation(s) in RCA: 168] [Impact Index Per Article: 28.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/17/2017] [Revised: 11/28/2017] [Accepted: 11/29/2017] [Indexed: 02/06/2023]
Abstract
Reproduction is controlled by the hypothalamic-pituitary-gonadal (HPG) axis. Gonadotropin-releasing hormone (GnRH) neurons play a central role in this axis through production of GnRH, which binds to a membrane receptor on pituitary gonadotrophs and stimulates the biosynthesis and secretion of follicle-stimulating hormone (FSH) and luteinizing hormone (LH). Multiple factors affect GnRH neuron migration, GnRH gene expression, GnRH pulse generator, GnRH secretion, GnRH receptor expression, and gonadotropin synthesis and release. Among them anosmin is involved in the guidance of the GnRH neuron migration, and a loss-of-function mutation in its gene leads to a failure of their migration from the olfactory placode to the hypothalamus, with consequent anosmic hypogonadotropic hypogonadism (Kallmann syndrome). There are also cases of hypogonadotropic hypogonadim with normal sense of smell, due to mutations of other genes. Another protein, kisspeptin plays a crucial role in the regulation of GnRH pulse generator and the pubertal development. GnRH is the main hypothalamic regulator of the release of gonadotropins. Finally, FSH and LH are the essential hormonal regulators of testicular functions, acting through their receptors in Sertoli and Leydig cells, respectively. The main features of the male HPG axis will be described in this review.
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Affiliation(s)
- Athina Kaprara
- Unit of Reproductive Endocrinology, Medical School, Aristotle University of Thessaloniki, Greece.
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21
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Spicer OS, Zmora N, Wong TT, Golan M, Levavi-Sivan B, Gothilf Y, Zohar Y. The gonadotropin-inhibitory hormone (Lpxrfa) system's regulation of reproduction in the brain-pituitary axis of the zebrafish (Danio rerio). Biol Reprod 2018; 96:1031-1042. [PMID: 28430864 DOI: 10.1093/biolre/iox032] [Citation(s) in RCA: 45] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2016] [Accepted: 04/17/2017] [Indexed: 11/14/2022] Open
Abstract
Gonadotropin-inhibitory hormone (GNIH) was discovered in quail with the ability to reduce gonadotropin expression/secretion in the pituitary. There have been few studies on GNIH orthologs in teleosts (LPXRFamide (Lpxrfa) peptides), which have provided inconsistent results. Therefore, the goal of this study was to determine the roles and modes of action by which Lpxrfa exerts its functions in the brain-pituitary axis of zebrafish (Danio rerio). We localized Lpxrfa soma to the ventral hypothalamus, with fibers extending throughout the brain and to the pituitary. In the preoptic area, Lpxrfa fibers interact with gonadotropin-releasing hormone 3 (Gnrh3) soma. In pituitary explants, zebrafish peptide Lpxrfa-3 downregulated luteinizing hormone beta subunit and common alpha subunit expression. In addition, Lpxrfa-3 reduced gnrh3 expression in brain slices, offering another pathway for Lpxrfa to exert its effects on reproduction. Receptor activation studies, in a heterologous cell-based system, revealed that all three zebrafish Lpxrfa peptides activate Lpxrf-R2 and Lpxrf-R3 via the PKA/cAMP pathway. Receptor activation studies demonstrated that, in addition to activating Lpxrf receptors, zebrafish Lpxrfa-2 and Lpxrfa-3 antagonize Kisspeptin-2 (Kiss2) activation of Kisspeptin receptor-1a (Kiss1ra). The fact that kiss1ra-expressing neurons in the preoptic area are innervated by Lpxrfa-ir fibers suggests an additional pathway for Lpxrfa action. Therefore, our results suggest that Lpxrfa may act as a reproductive inhibitory neuropeptide in the zebrafish that interacts with Gnrh3 neurons in the brain and with gonadotropes in the pituitary, while also potentially utilizing the Kiss2/Kiss1ra pathway.
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Affiliation(s)
- Olivia Smith Spicer
- Department of Marine Biotechnology, Institute of Marine and Environmental Technology, University of Maryland Baltimore County, Baltimore, Maryland, USA
| | - Nilli Zmora
- Department of Marine Biotechnology, Institute of Marine and Environmental Technology, University of Maryland Baltimore County, Baltimore, Maryland, USA
| | - Ten-Tsao Wong
- Department of Marine Biotechnology, Institute of Marine and Environmental Technology, University of Maryland Baltimore County, Baltimore, Maryland, USA
| | - Matan Golan
- Department of Animal Sciences, The Robert H. Smith Faculty of Agriculture, Food, and Environment, The Hebrew University of Jerusalem, Rehovot, Israel
| | - Berta Levavi-Sivan
- Department of Animal Sciences, The Robert H. Smith Faculty of Agriculture, Food, and Environment, The Hebrew University of Jerusalem, Rehovot, Israel
| | - Yoav Gothilf
- Department of Neurobiology, George S. Wise Faculty of Life Sciences and Sagol School of Neuroscience, Tel Aviv University, Tel Aviv, Israel
| | - Yonathan Zohar
- Department of Marine Biotechnology, Institute of Marine and Environmental Technology, University of Maryland Baltimore County, Baltimore, Maryland, USA
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22
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Yang L, Comninos AN, Dhillo WS. Intrinsic links among sex, emotion, and reproduction. Cell Mol Life Sci 2018; 75:2197-2210. [PMID: 29619543 PMCID: PMC5948280 DOI: 10.1007/s00018-018-2802-3] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2017] [Revised: 01/27/2018] [Accepted: 03/20/2018] [Indexed: 01/23/2023]
Abstract
Species survival is dependent on successful reproduction. This begins with a desire to mate, followed by selection of a partner, copulation and in monogamous mammals including humans, requires emotions and behaviours necessary to maintain partner bonds for the benefit of rearing young. Hormones are integral to all of these stages and not only mediate physiological and endocrine processes involved in reproduction, but also act as neuromodulators within limbic brain centres to facilitate the expression of innate emotions and behaviours required for reproduction. A significant body of work is unravelling the roles of several key hormones in the modulation of mood states and sexual behaviours; however, a full understanding of the integration of these intrinsic links among sexual and emotional brain circuits still eludes us. This review summarises the evidence to date and postulates future directions to identify potential psycho-neuroendocrine frameworks linking sexual and emotional brain processes with reproduction.
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Affiliation(s)
- Lisa Yang
- Section of Endocrinology and Investigative Medicine, Imperial College London, 6th Floor, Commonwealth Building, Hammersmith Hospital Campus, Du Cane Road, London, W12 ONN, UK
| | - Alexander N Comninos
- Section of Endocrinology and Investigative Medicine, Imperial College London, 6th Floor, Commonwealth Building, Hammersmith Hospital Campus, Du Cane Road, London, W12 ONN, UK
- Department of Endocrinology, Imperial College Healthcare NHS Trust, London, UK
| | - Waljit S Dhillo
- Section of Endocrinology and Investigative Medicine, Imperial College London, 6th Floor, Commonwealth Building, Hammersmith Hospital Campus, Du Cane Road, London, W12 ONN, UK.
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23
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Distribution of gonadotropin-inhibitory hormone (GnIH) in male Luchuan piglets. Gene Expr Patterns 2018; 28:42-53. [DOI: 10.1016/j.gep.2018.02.004] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2017] [Revised: 02/22/2018] [Accepted: 02/22/2018] [Indexed: 01/22/2023]
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24
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Shikano K, Bessho Y, Kato M, Iwakoshi-Ukena E, Taniuchi S, Furumitsu M, Tachibana T, Bentley GE, Kriegsfeld LJ, Ukena K. Localization and function of neurosecretory protein GM, a novel small secretory protein, in the chicken hypothalamus. Sci Rep 2018; 8:704. [PMID: 29335496 PMCID: PMC5768754 DOI: 10.1038/s41598-017-18822-9] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2017] [Accepted: 12/18/2017] [Indexed: 12/15/2022] Open
Abstract
Recently, we discovered a novel cDNA encoding the precursor of a small secretory protein, neurosecretory protein GL (NPGL), in the hypothalamic infundibulum of chickens. NPGL plays an important role in the regulation of growth and feeding. A database search indicated that the NPGL gene has a paralogous gene: neurosecretory protein GM (NPGM), also in chickens. We identified cDNA encoding the NPGM precursor in chickens. Morphological analysis showed that NPGM-containing cells are specifically localized in the medial mammillary nucleus (MM) and infundibular nucleus (IN) in the hypothalamus. In addition, we found that NPGM and NPGL are co-localized, especially in the MM. The expression levels of NPGM mRNA gradually decreased during post-hatch development, in contrast to those of NPGL mRNA. Moreover, we investigated the relationship between NPGM and other known factors. NPGM was found to be produced in histaminergic neurons in the MM. NPGM and histidine decarboxylase, a histamine-producing enzyme, displayed similar expression patterns during post-hatch development. Acute intracerebroventricular injection of NPGM decreased food intake, similar to the effect of histamine. To our knowledge, this is the first report of the localization and function of NPGM in the brain of vertebrates. These results will further advance the understanding mechanisms underlying energy homeostasis.
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Affiliation(s)
- Kenshiro Shikano
- Section of Behavioral Sciences, Graduate School of Integrated Arts and Sciences, Hiroshima University, Higashi, Hiroshima, 739-8521, Japan
| | - Yuki Bessho
- Section of Behavioral Sciences, Graduate School of Integrated Arts and Sciences, Hiroshima University, Higashi, Hiroshima, 739-8521, Japan
| | - Masaki Kato
- 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.,Department of Integrative Biology and the Helen Wills Neuroscience Institute, University of California at Berkeley, Berkeley, CA, 94720-3140, USA
| | - Shusuke Taniuchi
- Section of Behavioral Sciences, Graduate School of Integrated Arts and Sciences, Hiroshima University, Higashi, Hiroshima, 739-8521, Japan
| | - Megumi Furumitsu
- Section of Behavioral Sciences, Graduate School of Integrated Arts and Sciences, Hiroshima University, Higashi, Hiroshima, 739-8521, Japan
| | - Tetsuya Tachibana
- Department of Agrobiological Science, Faculty of Agriculture, Ehime University, Matsuyama, 790-8566, Japan
| | - George E Bentley
- Department of Integrative Biology and the Helen Wills Neuroscience Institute, University of California at Berkeley, Berkeley, CA, 94720-3140, USA
| | - Lance J Kriegsfeld
- Department of Psychology and the Helen Wills Neuroscience Institute, University of California at Berkeley, Berkeley, CA, 94720-3140, USA
| | - Kazuyoshi Ukena
- Section of Behavioral Sciences, Graduate School of Integrated Arts and Sciences, Hiroshima University, Higashi, Hiroshima, 739-8521, Japan. .,Department of Psychology and the Helen Wills Neuroscience Institute, University of California at Berkeley, Berkeley, CA, 94720-3140, USA.
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Kuenzel WJ. Mapping the brain of the chicken (Gallus gallus), with emphasis on the septal-hypothalamic region. Gen Comp Endocrinol 2018; 256:4-15. [PMID: 28923430 DOI: 10.1016/j.ygcen.2017.09.003] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/15/2017] [Revised: 07/14/2017] [Accepted: 09/13/2017] [Indexed: 01/28/2023]
Abstract
There has been remarkable progress in discoveries made in the avian brain, particularly over the past two decades. This review first highlights some of the discoveries made in the forebrain and credits the Avian Brain Nomenclature Forum, responsible for changing many of the terms found in the cerebrum and for stimulating collaborative research thereafter. The Forum facilitated communication among comparative neurobiologists by eliminating confusing and inaccurate names. The result over the past 15yearshas been a standardized use of avian forebrain terms. Nonetheless, additional changes are needed. The goal of the paper is to encourage a continuing effort to unify the nomenclature throughout the entire avian brain. To emphasize the need for consensus for a single name for each neural structure, I have selected specific structures in the septum and hypothalamus that our laboratory has been investigating, to demonstrate a lack of uniformity in names applied to conservative brain regions compared to the forebrain. The specific areas reviewed include the distributions of gonadotropin-releasing hormone neurons and their terminal fields in circumventricular organs, deep-brain photoreceptors, gonadotropin inhibitory neurons and a complex structure and function of the nucleus of the hippocampal commissure.
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Affiliation(s)
- Wayne J Kuenzel
- Poultry Science Center, University of Arkansas, Fayetteville, AR 72701, USA.
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Aliaga-Guerrero M, Paullada-Salmerón JA, Piquer V, Mañanós EL, Muñoz-Cueto JA. Gonadotropin-inhibitory hormone in the flatfish,Solea senegalensis: Molecular cloning, brain localization and physiological effects. J Comp Neurol 2017; 526:349-370. [DOI: 10.1002/cne.24339] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2017] [Revised: 10/11/2017] [Accepted: 10/12/2017] [Indexed: 12/14/2022]
Affiliation(s)
- María Aliaga-Guerrero
- 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); Puerto Real Spain
- INMAR-CACYTMAR Research Institutes, Puerto Real University Campus; 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); Puerto Real Spain
- INMAR-CACYTMAR Research Institutes, Puerto Real University Campus; Puerto Real Spain
| | - Vanesa Piquer
- Institute of Aquaculture of Torre la Sal, CSIC; Castellón 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); Puerto Real Spain
- INMAR-CACYTMAR Research Institutes, Puerto Real University Campus; Puerto Real Spain
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Zhu H, Chen Z, Shao X, Yu J, Wei C, Dai Z, Shi Z. Reproductiveaxis gene regulation during photostimulation and photorefractoriness in Yangzhou goose ganders. Front Zool 2017; 14:11. [PMID: 28250798 PMCID: PMC5324292 DOI: 10.1186/s12983-017-0200-6] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2016] [Accepted: 02/21/2017] [Indexed: 11/23/2022] Open
Abstract
Background The Yangzhou goose is a long-day breeding bird that has been increasingly produced in China. Artificial lighting programs are used for controlling its reproductive activities. This study investigated the regulations of photostimulation and photorefractoriness that govern the onset and cessation of the breeding period. Results Increasing the daily photoperiod from 8 to 12 h rapidly stimulated testis development and increased plasma testosterone concentrations, with peak levels being reached 2 months after the photoperiod increase. Subsequently, testicular activities, testicular weight, spermatogenesis, and plasma testosterone concentrations declined steadily and reached to the nadir at 5 months after the 12-hour photoperiod. Throughout the experiment, plasma concentrations of triiodothyronine and thyroxine changed in reciprocal fashions to that of testosterone. The stimulation of reproductive activities caused by the increasing photoperiod was associated with increases in gonadotropin-releasing hormone (GnRH), but decreases in gonadotropin-inhibitory hormone (GnIH) and vasoactive intestinal peptide (VIP) gene messenger RNA (mRNA) levels in the hypothalamus. In the pituitary gland, the levels of follicle-stimulating hormone (FSH) and luteinizing hormone (LH) mRNA abruptly increased during the longer 12-hour photoperiod. The occurrence of photorefractoriness was associated with increased GnIH gene transcription by over 250-fold, together with increased VIP mRNA levels in the hypothalamus, and then prolactin and thyroid-stimulating hormone in the pituitary gland. FSH receptor, LH receptor, and StAR mRNA levels in the testis changed in ways paralleling those of testicular weight and testosterone concentrations. Conclusions The seasonal reproductive activities in Yangzhou geese were directly stimulated by a long photoperiod via upregulation of GnRH gene transcription, downregulation of GnIH, VIP gene transcription, and stimulation of gonadotrophin. Development of photorefractoriness was characterized by hyper-regulation of GnIH gene transcription in the hypothalamus, in addition of upregulation of VIP and TRH gene transcription, and that of their receptors, in the pituitary gland.
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Affiliation(s)
- Huanxi Zhu
- Laboratory of Animal Improvement and Reproduction, Institute of Animal Science, Jiangsu Academy of Agricultural Sciences, Nanjing, 210014 China
| | - Zhe Chen
- Laboratory of Animal Improvement and Reproduction, Institute of Animal Science, Jiangsu Academy of Agricultural Sciences, Nanjing, 210014 China
| | - Xibin Shao
- Sunlake Swan Farm, Changzhou, 213101 China
| | - Jianning Yu
- Laboratory of Animal Improvement and Reproduction, Institute of Animal Science, Jiangsu Academy of Agricultural Sciences, Nanjing, 210014 China
| | - Chuankun Wei
- Laboratory of Animal Improvement and Reproduction, Institute of Animal Science, Jiangsu Academy of Agricultural Sciences, Nanjing, 210014 China
| | - Zichun Dai
- Laboratory of Animal Improvement and Reproduction, Institute of Animal Science, Jiangsu Academy of Agricultural Sciences, Nanjing, 210014 China
| | - Zhendan Shi
- Laboratory of Animal Improvement and Reproduction, Institute of Animal Science, Jiangsu Academy of Agricultural Sciences, Nanjing, 210014 China
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RFamide-related peptide-3 (RFRP-3) suppresses sexual maturation in a eusocial mammal. Proc Natl Acad Sci U S A 2017; 114:1207-1212. [PMID: 28096421 DOI: 10.1073/pnas.1616913114] [Citation(s) in RCA: 44] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
Neuroendocrine mechanisms underlying social inhibition of puberty are not well understood. Here, we use a model exhibiting the most profound case of pubertal suppression among mammals to explore a role for RFamide-related peptide-3 [RFRP-3; mammalian ortholog to gonadotropin-inhibitory hormone (GnIH)] in neuroendocrine control of reproductive development. Naked mole rats (NMRs) live in sizable colonies where breeding is monopolized by two to four dominant animals, and no other members exhibit signs of puberty throughout their lives unless they are removed from the colony. Because of its inhibitory action on the reproductive axis in other vertebrates, we investigated the role of RFRP-3 in social reproductive suppression in NMRs. We report that RFRP-3 immunofluorescence expression patterns and RFRP-3/GnRH cross-talk are largely conserved in the NMR brain, with the exception of the unique presence of RFRP-3 cell bodies in the arcuate nucleus (Arc). Immunofluorescence comparisons revealed that central expression of RFRP-3 is altered by reproductive status, with RFRP-3 immunoreactivity enhanced in the paraventricular nucleus, dorsomedial nucleus, and Arc of reproductively quiescent NMRs. We further observed that exogenous RFRP-3 suppresses gonadal steroidogenesis and mating behavior in NMRs given the opportunity to undergo puberty. Together, our findings establish a role for RFRP-3 in preserving reproductive immaturity, and challenge the view that stimulatory peptides are the ultimate gatekeepers of puberty.
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Jadhao AG, Pinelli C, D'Aniello B, Tsutsui K. Gonadotropin-inhibitory hormone (GnIH) in the amphibian brain and its relationship with the gonadotropin releasing hormone (GnRH) system: An overview. Gen Comp Endocrinol 2017; 240:69-76. [PMID: 27667155 DOI: 10.1016/j.ygcen.2016.09.006] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/29/2016] [Revised: 09/02/2016] [Accepted: 09/14/2016] [Indexed: 01/28/2023]
Abstract
It is well known that the hypothalamic neuropeptide gonadotropin-releasing hormone (GnRH) plays an important role as a primary factor regulating gonadotropin secretion in reproductive processes in vertebrates. The discovery of the presence of a gonadotropin-inhibitory hormone (GnIH) in the brains of birds has further contributed to our understanding of the reproduction control by the brain. GnIH plays a key role in inhibition of reproduction and acts on the pituitary gland and GnRH neurons via a novel G protein-coupled receptor (GPR147). GnIH decreases gonadotropin synthesis and release, thus inhibiting gonadal development and maintenance. The GnRH and GnIH neuronal peptidergic systems are well reported in mammals and birds, but limited information is available regarding their presence and localization in the brains of other vertebrate species, such as reptiles, amphibians and fishes. The aim of this review is to compile and update information on the localization of GnRH and GnIH neuronal systems, with a particular focus on amphibians, summarizing the neuroanatomical distribution of GnIH and GnRH and emphasizing the discovery of GnIH based on RFamide peptides and GnIH orthologous peptides found in other vertebrates and their functional significance.
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Affiliation(s)
- Arun G Jadhao
- Department of Zoology, RTM Nagpur University Campus, Nagpur 440 033, MS, India.
| | - Claudia Pinelli
- Department of Environmental, Biological, and Pharmaceutical Sciences & Technologies, Second University of Naples, 81100 Caserta, Italy
| | - Biagio D'Aniello
- Department of Biology, University of Naples "Federico II", 80126 Napoli, Italy
| | - Kazuyoshi Tsutsui
- Laboratory of Integrative Brain Sciences, Department of Biology and Centre for Medical Life Science, Waseda University, Tokyo 162-8480, Japan
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Hormonal Responses to a Potential Mate in Male Birds. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2017; 1001:137-149. [DOI: 10.1007/978-981-10-3975-1_9] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
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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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Ubuka T, Parhar I. Dual Actions of Mammalian and Piscine Gonadotropin-Inhibitory Hormones, RFamide-Related Peptides and LPXRFamide Peptides, in the Hypothalamic-Pituitary-Gonadal Axis. Front Endocrinol (Lausanne) 2017; 8:377. [PMID: 29375482 PMCID: PMC5768612 DOI: 10.3389/fendo.2017.00377] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/21/2017] [Accepted: 12/22/2017] [Indexed: 01/04/2023] Open
Abstract
Gonadotropin-inhibitory hormone (GnIH) is a hypothalamic neuropeptide that decreases gonadotropin synthesis and release by directly acting on the gonadotrope or by decreasing the activity of gonadotropin-releasing hormone (GnRH) neurons. GnIH is also called RFamide-related peptide in mammals or LPXRFamide peptide in fishes due to its characteristic C-terminal structure. The primary receptor for GnIH is GPR147 that inhibits cAMP production in target cells. Although most of the studies in mammals, birds, and fish have shown the inhibitory action of GnIH in the hypothalamic-pituitary-gonadal (HPG) axis, several in vivo studies in mammals and many in vivo and in vitro studies in fish have shown its stimulatory action. In mouse, although the firing rate of the majority of GnRH neurons is decreased, a small population of GnRH neurons is stimulated by GnIH. In hamsters, GnIH inhibits luteinizing hormone (LH) release in the breeding season when their endogenous LH level is high but stimulates LH release in non-breeding season when their LH level is basal. Besides different effects of GnIH on the HPG axis depending on the reproductive stages in fish, higher concentration or longer duration of GnIH administration can stimulate their HPG axis. These results suggest that GnIH action in the HPG axis is modulated by sex-steroid concentration, the action of neuroestrogen synthesized by the activity of aromatase stimulated by GnIH, estrogen membrane receptor, heteromerization and internalization of GnIH, GnRH, and estrogen membrane receptors. The inhibitory and stimulatory action of GnIH in the HPG axis may have a physiological role to maintain reproductive homeostasis according to developmental and reproductive stages.
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Affiliation(s)
- Takayoshi Ubuka
- Jeffrey Cheah School of Medicine and Health Sciences, Brain Research Institute Monash Sunway, Monash University Malaysia, Sunway, Malaysia
- *Correspondence: Takayoshi Ubuka,
| | - Ishwar Parhar
- Jeffrey Cheah School of Medicine and Health Sciences, Brain Research Institute Monash Sunway, Monash University Malaysia, 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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Eisthen HL, Theis KR. Animal-microbe interactions and the evolution of nervous systems. Philos Trans R Soc Lond B Biol Sci 2016; 371:20150052. [PMID: 26598731 DOI: 10.1098/rstb.2015.0052] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Animals ubiquitously interact with environmental and symbiotic microbes, and the effects of these interactions on animal physiology are currently the subject of intense interest. Nevertheless, the influence of microbes on nervous system evolution has been largely ignored. We illustrate here how taking microbes into account might enrich our ideas about the evolution of nervous systems. For example, microbes are involved in animals' communicative, defensive, predatory and dispersal behaviours, and have likely influenced the evolution of chemo- and photosensory systems. In addition, we speculate that the need to regulate interactions with microbes at the epithelial surface may have contributed to the evolutionary internalization of the nervous system.
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Affiliation(s)
- Heather L Eisthen
- Department of Integrative Biology, Michigan State University, 288 Farm Lane Rm 203, East Lansing, MI 48824, USA BEACON Center for the Study of Evolution in Action, 567 Wilson Road Rm 1441, East Lansing, MI 48824, USA
| | - Kevin R Theis
- BEACON Center for the Study of Evolution in Action, 567 Wilson Road Rm 1441, East Lansing, MI 48824, USA Department of Internal Medicine, University of Michigan Medical School, 1150 West Medical Center Drive, MSRB I Rm 1510A, Ann Arbor, MI 48109, USA
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Rudolph LM, Bentley GE, Calandra RS, Paredes AH, Tesone M, Wu TJ, Micevych PE. Peripheral and Central Mechanisms Involved in the Hormonal Control of Male and Female Reproduction. J Neuroendocrinol 2016; 28:10.1111/jne.12405. [PMID: 27329133 PMCID: PMC5146987 DOI: 10.1111/jne.12405] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/14/2016] [Revised: 05/25/2016] [Accepted: 06/20/2016] [Indexed: 12/18/2022]
Abstract
Reproduction involves the integration of hormonal signals acting across multiple systems to generate a synchronised physiological output. A critical component of reproduction is the luteinising hormone (LH) surge, which is mediated by oestradiol (E2 ) and neuroprogesterone interacting to stimulate kisspeptin release in the rostral periventricular nucleus of the third ventricle in rats. Recent evidence indicates the involvement of both classical and membrane E2 and progesterone signalling in this pathway. A metabolite of gonadotrophin-releasing hormone (GnRH), GnRH-(1-5), has been shown to stimulate GnRH expression and secretion, and has a role in the regulation of lordosis. Additionally, gonadotrophin release-inhibitory hormone (GnIH) projects to and influences the activity of GnRH neurones in birds. Stress-induced changes in GnIH have been shown to alter breeding behaviour in birds, demonstrating another mechanism for the molecular control of reproduction. Peripherally, paracrine and autocrine actions within the gonad have been suggested as therapeutic targets for infertility in both males and females. Dysfunction of testicular prostaglandin synthesis is a possible cause of idiopathic male infertility. Indeed, local production of melatonin and corticotrophin-releasing hormone could influence spermatogenesis via immune pathways in the gonad. In females, vascular endothelial growth factor A has been implicated in an angiogenic process that mediates development of the corpus luteum and thus fertility via the Notch signalling pathway. Age-induced decreases in fertility involve ovarian kisspeptin and its regulation of ovarian sympathetic innervation. Finally, morphological changes in the arcuate nucleus of the hypothalamus influence female sexual receptivity in rats. The processes mediating these morphological changes have been shown to involve the rapid effects of E2 controlling synaptogenesis in this hypothalamic nucleus. In summary, this review highlights new research in these areas, focusing on recent findings concerning the molecular mechanisms involved in the central and peripheral hormonal control of reproduction.
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Affiliation(s)
- L M Rudolph
- Department of Neurobiology, Laboratory of Neuroendocrinology, David Geffen School of Medicine at UCLA, Los Angeles, CA, USA
| | - G E Bentley
- Department of Integrative Biology, and Helen Wills Neuroscience Institute, University of California, Berkeley, Berkeley, CA, USA
| | - R S Calandra
- Instituto de Biología y Medicina Experimental (IBYME-CONICET), Buenos Aires, Argentina
| | - A H Paredes
- Laboratory of Neurobiochemistry, Faculty of Chemistry and Pharmaceutical Sciences, Universidad de Chile, Independencia, Santiago, Chile
| | - M Tesone
- Instituto de Biología y Medicina Experimental (IBYME-CONICET), Buenos Aires, Argentina
| | - T J Wu
- Department of Obstetrics and Gynecology, Center for Neuroscience and Regenerative Medicine, Uniformed Services University, Bethesda, MD, USA
| | - P E Micevych
- Department of Neurobiology, Laboratory of Neuroendocrinology, David Geffen School of Medicine at UCLA, Los Angeles, CA, USA
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Rastogi A, Malik S, Rani S, Kumar V. Changes in brain peptides associated with reproduction and energy homeostasis in photosensitive and photorefractory migratory redheaded buntings. Gen Comp Endocrinol 2016; 230-231:67-75. [PMID: 27038875 DOI: 10.1016/j.ygcen.2016.03.031] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/12/2015] [Revised: 03/09/2016] [Accepted: 03/26/2016] [Indexed: 11/16/2022]
Abstract
Present study examined the expression of brain peptides associated with the reproduction and energy homeostasis (GnRH/GnIH, NPY/VIP), and assessed their possible functional association in the photosensitive (non-breeding, pre-breeding), photostimulated (breeding) and photorefractory (post-breeding) migratory redheaded buntings (Emberiza bruniceps), using double-labeled immunohistochemistry. Particularly, we measured immunoreactive (-ir) cell numbers, per cent cell area and cell optical density (OD) in the preoptic area (GnRH-I), midbrain (GnRH-II), paraventricular nucleus (GnIH), dorsomedial hypothalamus, DMH and infundibular complex, INc (NPY and VIP), and lateral septal organ (VIP) of buntings kept under natural photoperiods at the wintering latitude (26°55'N). There was a significant seasonal difference in GnRH-I, not GnRH-II, with reduced -ir cells in the photosensitive and photorefractory buntings, and notably with increased cell OD between the refractory and non-breeding states with no increase in testis size. Also, increased cell OD of GnIH neurons in non-breeding state indicated its role in the maintenance of small testes during the post-refractory period. Overall, seasonal changes in GnRH-I and GnIH were found consistent with their suggested roles in reproductive regulation of absolute photorefractory birds. Further, there was a significant seasonal change in cell OD of NPY neurons in DMH, not the INc. In contrast, VIP immunoreactivity was seasonally altered, with a significantly higher VIP-ir cells in breeding than the pre-breeding state. Finally, close proximity between perikarya with fibres suggested functional interactions between the GnRH and GnIH, and NPY and VIP. Thus, seasonal plasticity of brain peptides is perhaps the part of neural regulation of seasonal reproduction and associated energy homeostasis in migratory songbirds.
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Affiliation(s)
- Ashutosh Rastogi
- Department of Zoology, University of Lucknow, Lucknow 226 007, India
| | - Shalie Malik
- Department of Zoology, University of Lucknow, Lucknow 226 007, India
| | - Sangeeta Rani
- Department of Zoology, University of Lucknow, Lucknow 226 007, India
| | - Vinod Kumar
- Department of Zoology, University of Delhi, Delhi 110 007, India.
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Ogawa S, Sivalingam M, Biran J, Golan M, Anthonysamy RS, Levavi-Sivan B, Parhar IS. Distribution of LPXRFa, a gonadotropin-inhibitory hormone ortholog peptide, and LPXRFa receptor in the brain and pituitary of the tilapia. J Comp Neurol 2016; 524:2753-75. [PMID: 26917324 DOI: 10.1002/cne.23990] [Citation(s) in RCA: 43] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2015] [Revised: 02/18/2016] [Accepted: 02/19/2016] [Indexed: 11/09/2022]
Abstract
In vertebrates, gonadotropin-releasing hormone (GnRH) and gonadotropin-inhibitory hormone (GnIH), respectively, regulate reproduction in positive and negative manners. GnIH belongs to the LPXRFa family of peptides previously identified in mammalian and nonmammalian vertebrates. Studying the detailed distribution of LPXRFa as well as its receptor (LPXRFa-R) in the brain and pituitary is important for understanding their multiple action sites and potential functions. However, the distribution of LPXRFa and LPXRFa-R has not been studied in teleost species, partially because of the lack of fish-specific antibodies. Therefore, in the present study, we generated specific antibodies against LPXRFa and its receptor from Nile tilapia (Oreochromis niloticus), and examined their distributions in the brain and pituitary by immunohistochemistry. Tilapia LPXRFa-immunoreactive neurons lie in the posterior ventricular nucleus of the caudal preoptic area, whereas LPXRFa-R-immunoreactive cells are distributed widely. Double immunofluorescence showed that neither LPXRFa-immunoreactive fibers nor LPXRFa-R is closely associated or coexpressed with GnRH1, GnRH3, or kisspeptin (Kiss2) neurons. In the pituitary, LPXRFa fibers are closely associated with gonadotropic endocrine cells [expressing luteinizing hormone (LH) and follicle-stimulating hormone (FSH)], with adrenocorticomelanotropic cells [corticotropin (ACTH) and α-melanotropin (α-MSH)], and with somatolactin endocrine cells. In contrast, LPXRFa-R are expressed only in LH, ACTH, and α-MSH cells. These results suggest that LPXRFa and LPXRFa-R signaling acts directly on the pituitary cells independent from GnRH or kisspeptin and could play multiple roles in reproductive and nonreproductive functions in teleosts. J. Comp. Neurol. 524:2753-2775, 2016. © 2016 Wiley Periodicals, Inc.
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Affiliation(s)
- Satoshi Ogawa
- Brain Research Institute, Jeffrey Cheah School of Medicine and Health Sciences, Monash University Malaysia, Selangor, Malaysia
| | - Mageswary Sivalingam
- Brain Research Institute, Jeffrey Cheah School of Medicine and Health Sciences, Monash University Malaysia, Selangor, Malaysia
| | - Jakob Biran
- Department of Animal Sciences, The Robert H Smith Faculty of Agriculture, Food, and Environment, Hebrew University of Jerusalem, Rehovot 76100, Israel
| | - Matan Golan
- Department of Animal Sciences, The Robert H Smith Faculty of Agriculture, Food, and Environment, Hebrew University of Jerusalem, Rehovot 76100, Israel
| | - Rachel Shalini Anthonysamy
- Brain Research Institute, Jeffrey Cheah School of Medicine and Health Sciences, Monash University Malaysia, Selangor, Malaysia
| | - Berta Levavi-Sivan
- Department of Animal Sciences, The Robert H Smith Faculty of Agriculture, Food, and Environment, Hebrew University of Jerusalem, Rehovot 76100, Israel
| | - Ishwar S Parhar
- Brain Research Institute, Jeffrey Cheah School of Medicine and Health Sciences, Monash University Malaysia, Selangor, Malaysia
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Ogura Y, Haraguchi S, Nagino K, Ishikawa K, Fukahori Y, Tsutsui K. 7α-Hydroxypregnenolone regulates diurnal changes in sexual behavior of male quail. Gen Comp Endocrinol 2016; 227:130-5. [PMID: 26608258 DOI: 10.1016/j.ygcen.2015.11.010] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/07/2015] [Revised: 11/14/2015] [Accepted: 11/17/2015] [Indexed: 11/16/2022]
Abstract
In the Japanese quail, 7α-hydroxypregnenolone, a previously undescribed avian neurosteroid, is actively produced in the brain. 7α-Hydroxypregnenolone acts as a novel neuronal activator to stimulate locomotor activity of quail. Therefore, in this study, we determined whether 7α-hydroxypregnenolone changes the expression of sexual behavior in Japanese quail. We first measured diurnal changes in sexual behavior of male quail exposed to a long-day photoperiod. We found that sexual behavior of male quail was high in the morning when endogenous 7α-hydroxypregnenolone level is high. Subsequently, we centrally administered 7α-hydroxypregnenolone in the evening when endogenous 7α-hydroxypregnenolone level is low. In the 30 min after intracerebroventricular (ICV) injection, 7α-hydroxypregnenolone dose dependently increased the frequency of sexual behavior of male quail. However, 7β-hydroxypregnenolone, a stereoisomer of 7α-hydroxypregnenolone, did not effect on the frequency of sexual behavior of male quail. In addition, to confirm the action of 7α-hydroxypregnenolone on sexual behavior, male birds received an ICV injection of ketoconazole, an inhibitor of cytochrome P450s, and behavioral experiments were performed in the morning. Ketoconazole significantly decreased the frequency of sexual behavior of male quail, whereas administration of 7α-hydroxypregnenolone to ketoconazole-treated males increased the frequency of their sexual behavior. These results indicate that 7α-hydroxypregnenolone regulates diurnal changes in sexual behavior of male quail.
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Affiliation(s)
- Yuki Ogura
- Laboratory of Integrative Brain Sciences, Department of Biology, Waseda University, and Center for Medical Life Science of Waseda University, Tokyo 162-8480, Japan
| | - Shogo Haraguchi
- Laboratory of Integrative Brain Sciences, Department of Biology, Waseda University, and Center for Medical Life Science of Waseda University, Tokyo 162-8480, Japan.
| | - Koki Nagino
- Laboratory of Integrative Brain Sciences, Department of Biology, Waseda University, and Center for Medical Life Science of Waseda University, Tokyo 162-8480, Japan
| | - Kei Ishikawa
- Laboratory of Integrative Brain Sciences, Department of Biology, Waseda University, and Center for Medical Life Science of Waseda University, Tokyo 162-8480, Japan
| | - Yoko Fukahori
- Laboratory of Integrative Brain Sciences, Department of Biology, Waseda University, and Center for Medical Life Science of Waseda University, Tokyo 162-8480, Japan
| | - Kazuyoshi Tsutsui
- Laboratory of Integrative Brain Sciences, Department of Biology, Waseda University, and Center for Medical Life Science of Waseda University, Tokyo 162-8480, Japan.
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Tsutsui K. How to contribute to the progress of neuroendocrinology: New insights from discovering novel neuropeptides and neurosteroids regulating pituitary and brain functions. Gen Comp Endocrinol 2016; 227:3-15. [PMID: 26145291 DOI: 10.1016/j.ygcen.2015.05.019] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/24/2015] [Revised: 04/28/2015] [Accepted: 05/07/2015] [Indexed: 12/29/2022]
Abstract
Obtaining new insights by discovering novel neuropeptides and neurosteroids regulating pituitary and brain functions is essential for the progress of neuroendocrinology. At the beginning of 1970s, gonadotropin-releasing hormone (GnRH) was discovered in mammals. Since then, it was generally accepted that GnRH is the only hypothalamic neuropeptide regulating gonadotropin release in vertebrates. In 2000, however, gonadotropin-inhibitory hormone (GnIH), a novel hypothalamic neuropeptide that actively inhibits gonadotropin release, was discovered in quail. The follow-up studies demonstrated that GnIH acts as a new key player for regulation of reproduction across vertebrates. It now appears that GnIH acts on the pituitary and the brain to serve a number of behavioral and physiological functions. On the other hand, a new concept has been established that the brain synthesizes steroids, called neurosteroids. The formation of neurosteroids in the brain was originally demonstrated in mammals and subsequently in other vertebrates. Recently, 7α-hydroxypregnenolone was discovered as a novel bioactive neurosteroid inducing locomotor behavior of vertebrates, indicating that neurosteroidogenesis in the brain is still incompletely elucidated in vertebrates. At the beginning of 2010s, it was further found that the pineal gland actively produces neurosteroids. Pineal neurosteroids act on the brain to regulate locomotor rhythms and neuronal survival. Furthermore, the interaction of neuropeptides and neurosteroids is becoming clear. GnIH decreases aggressive behavior by regulating neuroestrogen synthesis in the brain. This review summarizes these new insights by discovering novel neuropeptides and neurosteroids in the field of 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 162-8480, Japan.
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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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Bédécarrats GY, Baxter M, Sparling B. An updated model to describe the neuroendocrine control of reproduction in chickens. Gen Comp Endocrinol 2016; 227:58-63. [PMID: 26414126 DOI: 10.1016/j.ygcen.2015.09.023] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/27/2015] [Accepted: 09/22/2015] [Indexed: 01/03/2023]
Abstract
Since its first identification in quail 15 years ago, gonadotropin inhibitory hormone (GnIH) has become a central regulator of reproduction in avian species. In this review, we have revisited our original model published in 2009 to incorporate recent experimental evidence suggesting that GnIH acts as a molecular switch during the integration of multiple external and internal cues that allow sexual maturation to proceed in chickens. Furthermore, we discuss the regulation of a dual inhibitory/stimulatory control of the hypothalamo-pituitary-gonadal axis involving the interaction between GnIH and gonadotropin releasing hormone (GnRH). Finally, beyond seasonality, we also propose that GnIH along with this dual control may be responsible for the circadian control of ovulation in chickens, allowing eggs to be laid in a synchronized manner.
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Affiliation(s)
- Grégoy Y Bédécarrats
- Department of Animal and Poultry Science, University of Guelph, 50 Stone Road East, Guelph N1G 2W1, ON, Canada.
| | - Mikayla Baxter
- Department of Animal and Poultry Science, University of Guelph, 50 Stone Road East, Guelph N1G 2W1, ON, Canada.
| | - Brandi Sparling
- Department of Animal and Poultry Science, University of Guelph, 50 Stone Road East, Guelph N1G 2W1, ON, Canada.
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Ubuka T, Son YL, Tsutsui K. Molecular, cellular, morphological, physiological and behavioral aspects of gonadotropin-inhibitory hormone. Gen Comp Endocrinol 2016; 227:27-50. [PMID: 26409890 DOI: 10.1016/j.ygcen.2015.09.009] [Citation(s) in RCA: 71] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/01/2015] [Revised: 09/09/2015] [Accepted: 09/11/2015] [Indexed: 12/15/2022]
Abstract
Gonadotropin-inhibitory hormone (GnIH) is a hypothalamic neuropeptide that was isolated from the brains of Japanese quail in 2000, which inhibited luteinizing hormone release from the anterior pituitary gland. Here, we summarize the following fifteen years of researches that investigated on the mechanism of GnIH actions at molecular, cellular, morphological, physiological, and behavioral levels. The unique molecular structure of GnIH peptide is in its LPXRFamide (X=L or Q) motif at its C-terminal. The primary receptor for GnIH is GPR147. The cell signaling pathway triggered by GnIH is initiated by inhibiting adenylate cyclase and decreasing cAMP production in the target cell. GnIH neurons regulate not only gonadotropin synthesis and release in the pituitary, but also regulate various neurons in the brain, such as GnRH1, GnRH2, dopamine, POMC, NPY, orexin, MCH, CRH, oxytocin, and kisspeptin neurons. GnIH and GPR147 are also expressed in gonads and they may regulate steroidogenesis and germ cell maturation in an autocrine/paracrine manner. GnIH regulates reproductive development and activity. In female mammals, GnIH may regulate estrous or menstrual cycle. GnIH is also involved in the regulation of seasonal reproduction, but GnIH may finely tune reproductive activities in the breeding seasons. It is involved in stress responses not only in the brain but also in gonads. GnIH may inhibit male socio-sexual behavior by stimulating the activity of cytochrome P450 aromatase in the brain and stimulates feeding behavior by modulating the activities of hypothalamic and central amygdala neurons.
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Affiliation(s)
- Takayoshi Ubuka
- Department of Biology, Waseda University, 2-2 Wakamatsu-cho, Shinjuku, Tokyo 162-8480, Japan; Brain Research Institute Monash Sunway (BRIMS) of the Jeffrey Cheah School of Medicine and Health Sciences, Monash University Malaysia, Petaling Jaya 46150, Malaysia.
| | - You Lee Son
- Department of Biology, Waseda University, 2-2 Wakamatsu-cho, Shinjuku, Tokyo 162-8480, Japan
| | - Kazuyoshi Tsutsui
- Department of Biology, Waseda University, 2-2 Wakamatsu-cho, Shinjuku, Tokyo 162-8480, Japan.
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Henningsen JB, Gauer F, Simonneaux V. RFRP Neurons - The Doorway to Understanding Seasonal Reproduction in Mammals. Front Endocrinol (Lausanne) 2016; 7:36. [PMID: 27199893 PMCID: PMC4853402 DOI: 10.3389/fendo.2016.00036] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/28/2016] [Accepted: 04/18/2016] [Indexed: 01/03/2023] Open
Abstract
Seasonal control of reproduction is critical for the perpetuation of species living in temperate zones that display major changes in climatic environment and availability of food resources. In mammals, seasonal cues are mainly provided by the annual change in the 24-h light/dark ratio (i.e., photoperiod), which is translated into the nocturnal production of the pineal hormone melatonin. The annual rhythm in this melatonin signal acts as a synchronizer ensuring that breeding occurs when environmental conditions favor survival of the offspring. Although specific mechanisms might vary among seasonal species, the hypothalamic RF (Arg-Phe) amide-related peptides (RFRP-1 and -3) are believed to play a critical role in the central control of seasonal reproduction and in all seasonal species investigated, the RFRP system is persistently inhibited in short photoperiod. Central chronic administration of RFRP-3 in short day-adapted male Syrian hamsters fully reactivates the reproductive axis despite photoinhibitory conditions, which highlights the importance of the seasonal changes in RFRP expression for proper regulation of the reproductive axis. The acute effects of RFRP peptides, however, depend on species and photoperiod, and recent studies point toward a different role of RFRP in regulating female reproductive activity. In this review, we summarize the recent advances made to understand the role and underlying mechanisms of RFRP in the seasonal control of reproduction, primarily focusing on mammalian species.
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Affiliation(s)
- Jo B. Henningsen
- Institut des Neurosciences Cellulaires et Intégratives, Centre national de la recherche scientifique (CNRS), University of Strasbourg, Strasbourg, France
| | - François Gauer
- Institut des Neurosciences Cellulaires et Intégratives, Centre national de la recherche scientifique (CNRS), University of Strasbourg, Strasbourg, France
| | - Valérie Simonneaux
- Institut des Neurosciences Cellulaires et Intégratives, Centre national de la recherche scientifique (CNRS), University of Strasbourg, Strasbourg, France
- *Correspondence: Valérie Simonneaux,
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Hypothalamic inhibition of socio-sexual behaviour by increasing neuroestrogen synthesis. Nat Commun 2015; 5:3061. [PMID: 24430094 PMCID: PMC3905723 DOI: 10.1038/ncomms4061] [Citation(s) in RCA: 95] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2013] [Accepted: 12/03/2013] [Indexed: 01/18/2023] Open
Abstract
Gonadotropin-inhibitory hormone (GnIH) is a hypothalamic neuropeptide that inhibits gonadotropin secretion and socio-sexual behaviours. Oestrogen (neuroestrogen) synthesized in the brain from androgen by aromatase regulates male socio-sexual behaviours. Here we show that GnIH directly activates aromatase and increases neuroestrogen synthesis in the preoptic area (POA) and inhibits socio-sexual behaviours of male quail. Aromatase activity and neuroestrogen concentration in the POA are low in the morning when the birds are active, but neuroestrogen synthesis gradually increases until the evening when the birds become inactive. Centrally administered GnIH in the morning increases neuroestrogen synthesis in the POA and decreases socio-sexual behaviours. Centrally administered 17β-oestradiol at higher doses also inhibits socio-sexual behaviours in the morning. These results suggest that GnIH inhibits male socio-sexual behaviours by increasing neuroestrogen synthesis beyond its optimum concentration for the expression of socio-sexual behaviours. This is the first demonstration of any hypothalamic neuropeptide that directly regulates neuroestrogen synthesis.
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Kumari Y, Rani S, Tsutsui K, Kumar V. Duration of melatonin regulates seasonal plasticity in subtropical Indian weaver bird, Ploceus philippinus. Gen Comp Endocrinol 2015; 220:46-54. [PMID: 24932714 DOI: 10.1016/j.ygcen.2014.06.004] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/30/2014] [Revised: 05/21/2014] [Accepted: 06/05/2014] [Indexed: 10/25/2022]
Abstract
Day length regulates seasonal plasticity connected with reproduction in birds. Rhythmic pineal melatonin secretion is a reliable indicator of the night length, hence day length. Removal of rhythmic melatonin secretion by exposure to constant bright light (LLbright) or by pinealectomy renders several species of songbirds including Indian weaver bird (Ploceus philippinus) arrhythmic. Present study investigated whether rhythmic melatonin is involved in the regulation of key reproductive neuropeptides (GnRH I and GnIH) and reproduction linked neural changes, viz. song control nuclei, in Indian weaver birds. Two experiments were performed using birds in an arrhythmic condition with low (under LLbright) or no (in the absence of pineal gland) endogenous melatonin. In experiment I, three groups of birds (n=5 each) entrained to 12L:12D were exposed to LLbright (25lux) for two weeks. Beginning on day 15 of LLbright, a control group received vehicle for 16h and two treatment groups were given melatonin in drinking water for 8h or 16h. In experiment II, one group of sham-operated and three groups of pinealectomized birds (n=5 each) entrained to 12L:12D were exposed to constant dim light (LLdim, 0.5lux). Beginning on day 15 of LLdim, three groups received similar treatment as in experiment I. Birds were perfused after thirty cycles of the melatonin treatment, and brain sections were immunohistochemically double-labeled for GnRH I and GnIH or Nissl stained. Activity was recorded throughout the experiments, while body mass and testes were measured at the beginning and end of the experiment. Birds were synchronized with melatonin cycles and measured the duration of melatonin as "night". Pinealectomized birds that received 16h of melatonin had significantly higher GnIH-ir cells than those received 8h melatonin; there was no difference in the GnRH I immunoreactivity between two treatment groups however. Intact birds that received long duration melatonin cycles exhibited small song control nuclei, specifically the high vocal center (HVC) and the robust nucleus of the arcopallium (RA), while birds that received short duration melatonin or no melatonin exhibited large HVC and RA. Thus, melatonin possibly regulates seasonal reproduction via GnIH secretion, and also controls seasonal neuroplasticity in the song control system in songbirds.
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Affiliation(s)
- Yatinesh Kumari
- DST-IRHPA Center for Excellence in Biological Rhythms Research, Department of Zoology, University of Lucknow, Lucknow 226 007, India
| | - Sangeeta Rani
- DST-IRHPA Center for Excellence in Biological Rhythms Research, Department of Zoology, University of Lucknow, Lucknow 226 007, India
| | | | - Vinod Kumar
- DST-IRHPA Center for Excellence in Biological Rhythms Research, Department of Zoology, University of Delhi, Delhi 110 007, India.
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Tran PV, Chowdhury VS, Nagasawa M, Furuse M. Changes in free amino acid and monoamine concentrations in the chick brain associated with feeding behavior. SPRINGERPLUS 2015; 4:252. [PMID: 26191470 PMCID: PMC4501338 DOI: 10.1186/s40064-015-1058-8] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/15/2015] [Accepted: 05/26/2015] [Indexed: 11/20/2022]
Abstract
Domesticated chicks are precocial and therefore have relatively well-developed feeding behavior. The role of hypothalamic neuropeptides in food-intake regulation in chicks has been reported for decades. However, we hypothesized that nutrients and their metabolites in the brain may be involved in food intake in chicks because these animals exhibit a very frequent feeding pattern. Therefore, the purpose of this study was to examine the feeding behavior of chicks as well as the associated changes in free amino acid and monoamine concentrations in the chick brain. The feeding behavior of chicks was recorded continuously for 6 h. The next day, brain and blood samples were collected when the chicks either attempted to have food (hungry group) or turned food down (satiated group), in order to analyze the concentrations of the free amino acids and monoamines. We confirmed that the feeding behavior of neonatal chicks was characterized by short resting periods between very brief times spent on food intake. Several free amino acids in the mesencephalon were significantly lower in the satiated group than in the hungry group, while l-histidine and l-glutamine were significantly higher. Notably, there was no change in the free amino acid concentrations in other brain regions or plasma. As for monoamines, serotonin and norepinephrine were significantly lower in the mesencephalon of the hungry group compared with the satiated group, but 5 hydroxyindolacetic acid (5-HIAA) was higher. In addition, serotonin and norepinephrine levels were significantly higher in the brain stem of the hungry chicks compared with the satiated group, but levels of 5-HIAA and homovanillic acid were lower. Levels of both dopamine and its metabolite, 3,4-dihydroxyphenylacetic acid, were significantly higher in the diencephalon and telencephalon of the chicks in the hungry group. In conclusion, the changes in the free amino acids and monoamines in the brain may have some role in the feeding behavior of neonatal chicks.
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Affiliation(s)
- Phuong V Tran
- Faculty of Agriculture, Laboratory of Regulation in Metabolism and Behavior, Graduate School of Bioresource and Bioenvironmental Science, Kyushu University, Fukuoka, 812-8581 Japan
| | - Vishwajit S Chowdhury
- Division for Experimental Natural Science, Faculty of Arts and Science, Kyushu University, Fukuoka, 819-0395 Japan
| | - Mao Nagasawa
- Faculty of Agriculture, Laboratory of Regulation in Metabolism and Behavior, Graduate School of Bioresource and Bioenvironmental Science, Kyushu University, Fukuoka, 812-8581 Japan
| | - Mitsuhiro Furuse
- Faculty of Agriculture, Laboratory of Regulation in Metabolism and Behavior, Graduate School of Bioresource and Bioenvironmental Science, Kyushu University, Fukuoka, 812-8581 Japan
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Wang Q, Qi X, Guo Y, Li S, Zhang Y, Liu X, Lin H. Molecular identification of GnIH/GnIHR signal and its reproductive function in protogynous hermaphroditic orange-spotted grouper (Epinephelus coioides). Gen Comp Endocrinol 2015; 216:9-23. [PMID: 25943851 DOI: 10.1016/j.ygcen.2015.04.016] [Citation(s) in RCA: 54] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/04/2014] [Revised: 04/24/2015] [Accepted: 04/25/2015] [Indexed: 11/21/2022]
Abstract
Gonadotropin-inhibitory hormone (GnIH) and its receptor (GnIHR) play an important role in reproduction regulation in birds, mammals and some teleost species. In protogynous hermaphroditic orange-spotted grouper (Epinephelus coioides), the GnIH/GnIHR signaling pathway and its reproductive function have not been addressed yet. In this study, GnIH and GnIHR in orange-spotted grouper were characterized. gGnIH possessed three putative peptides (gGnIH-I, -II, -III), while gGnIHR showed the characteristics of G protein-coupled receptor and was clustered with GPR147. Functional assays demonstrated that three synthetic gGnIH peptides significantly decreased the forskolin-induced CRE promoter activity, but only gGnIH-I could significantly decrease SRE promoter activity in COS-7 cells transfected with gGnIHR. During the process of ovarian differentiation and development, gGnIH mRNA level in hypothalamus was low at the gonadal primordium stage with gonia, then increased significantly at the early differentiated gonad with primary growth oocytes, while decreased significantly at the developing gonads with cortical-alveolus and vitellogenic stage oocytes. During MT-induced sex reversal, gGnIH mRNA level in hypothalamus increased significantly when the fish completely reversed from female to male. However, gGnIHR mRNA level in pituitary decreased significantly in intersex and completely reversed male fish. Intraperitoneal injection (i.p.) of three gGnIH peptides significantly decreased GnRH1 mRNA levels in hypothalamus, and gGnIH-II significantly inhibited synthesis of LHβ in pituitary. In summary, we firstly identified the GnIH/GnIHR signal in protogynous orange-spotted grouper, which might be involved in the regulation of the reproductive function of sex differentiation, gonadal development and sex reversal via regulating the synthesis of both GnRH and GtH.
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Affiliation(s)
- Qingqing Wang
- State Key Laboratory of Biocontrol, The Guangdong Province Key Laboratory for Aquatic Economic Animals, and Institute of Aquatic Economic Animals, School of Life Sciences, Sun Yat-Sen University, Guangzhou 510275, China
| | - Xin Qi
- State Key Laboratory of Biocontrol, The Guangdong Province Key Laboratory for Aquatic Economic Animals, and Institute of Aquatic Economic Animals, School of Life Sciences, Sun Yat-Sen University, Guangzhou 510275, China
| | - Yin Guo
- State Key Laboratory of Biocontrol, The Guangdong Province Key Laboratory for Aquatic Economic Animals, and Institute of Aquatic Economic Animals, School of Life Sciences, Sun Yat-Sen University, Guangzhou 510275, China
| | - Shuisheng Li
- State Key Laboratory of Biocontrol, The Guangdong Province Key Laboratory for Aquatic Economic Animals, and Institute of Aquatic Economic Animals, School of Life Sciences, Sun Yat-Sen University, Guangzhou 510275, China
| | - Yong Zhang
- State Key Laboratory of Biocontrol, The Guangdong Province Key Laboratory for Aquatic Economic Animals, and Institute of Aquatic Economic Animals, School of Life Sciences, Sun Yat-Sen University, Guangzhou 510275, China
| | - Xiaochun Liu
- State Key Laboratory of Biocontrol, The Guangdong Province Key Laboratory for Aquatic Economic Animals, and Institute of Aquatic Economic Animals, School of Life Sciences, Sun Yat-Sen University, Guangzhou 510275, China.
| | - Haoran Lin
- State Key Laboratory of Biocontrol, The Guangdong Province Key Laboratory for Aquatic Economic Animals, and Institute of Aquatic Economic Animals, School of Life Sciences, Sun Yat-Sen University, Guangzhou 510275, China.
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Kuenzel WJ, Kang SW, Zhou ZJ. Exploring avian deep-brain photoreceptors and their role in activating the neuroendocrine regulation of gonadal development. Poult Sci 2015. [PMID: 25828571 DOI: 10.3382/ps.2014-04370] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
In the eyes of mammals, specialized photoreceptors called intrinsically photosensitive retinal ganglion cells (ipRGC) have been identified that sense photoperiodic or daylight exposure, providing them over time with seasonal information. Detectors of photoperiods are critical in vertebrates, particularly for timing the onset of reproduction each year. In birds, the eyes do not appear to monitor photoperiodic information; rather, neurons within at least 4 different brain structures have been proposed to function in this capacity. Specialized neurons, called deep brain photoreceptors (DBP), have been found in the septum and 3 hypothalamic areas. Within each of the 4 brain loci, one or more of 3 unique photopigments, including melanopsin, neuropsin, and vertebrate ancient opsin, have been identified. An experiment was designed to characterize electrophysiological responses of neurons proposed to be avian DBP following light stimulation. A second study used immature chicks raised under short-day photoperiods and transferred to long day lengths. Gene expression of photopigments was then determined in 3 septal-hypothalamic regions. Preliminary electrophysiological data obtained from patch-clamping neurons in brain slices have shown that bipolar neurons in the lateral septal organ responded to photostimulation comparable with mammalian ipRGC, particularly by showing depolarization and a delayed, slow response to directed light stimulation. Utilizing real-time reverse-transcription PCR, it was found that all 3 photopigments showed significantly increased gene expression in the septal-hypothalamic regions in chicks on the third day after being transferred to long-day photoperiods. Each dissected region contained structures previously proposed to have DBP. The highly significant increased gene expression for all 3 photopigments on the third, long-day photoperiod in brain regions proposed to contain 4 structures with DBP suggests that all 3 types of DBP (melanopsin, neuropsin, and vertebrate ancient opsin) in more than one neural site in the septal-hypothalamic area are involved in reproductive function. The neural response to light of at least 2 of the proposed DBP in the septal/hypothalamic region resembles the primitive, functional, sensory ipRGC well characterized in mammals.
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Affiliation(s)
- Wayne J Kuenzel
- Department of Poultry Science, University of Arkansas, Fayetteville 72701
| | - Seong W Kang
- Department of Poultry Science, University of Arkansas, Fayetteville 72701
| | - Z Jimmy Zhou
- Department of Ophthalmology and Visual Science, Yale University School of Medicine, New Haven, CT 06510
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Bédécarrats GY. Control of the reproductive axis: Balancing act between stimulatory and inhibitory input. Poult Sci 2015; 94:810-5. [DOI: 10.3382/ps/peu042] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
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Kuenzel WJ, Kang SW, Zhou ZJ. Exploring avian deep-brain photoreceptors and their role in activating the neuroendocrine regulation of gonadal development. Poult Sci 2015; 94:786-98. [DOI: 10.3382/ps.2014-4370] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
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