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Yamaguchi Y, Takagi W, Kaiya H, Konno N, Yoshida MA, Kuraku S, Hyodo S. Phylogenetic and functional properties of hagfish neurohypophysial hormone receptors distinct from their jawed vertebrate counterparts. Gen Comp Endocrinol 2023; 336:114257. [PMID: 36868365 DOI: 10.1016/j.ygcen.2023.114257] [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: 11/16/2022] [Revised: 02/26/2023] [Accepted: 02/27/2023] [Indexed: 03/05/2023]
Abstract
Vertebrate neurohypophysial hormones, i.e., vasopressin- and oxytocin-family peptides, exert versatile physiological actions via distinct G protein-coupled receptors. The neurohypophysial hormone receptor (NHR) family was classically categorized into four subtypes (V1aR, V1bR, V2R and OTR), while recent studies have identified seven subtypes (V1aR, V1bR, V2aR, V2bR, V2cR, V2dR and OTR; V2aR corresponds to the conventional V2R). The vertebrate NHR family were diversified via multiple gene duplication events at different scales. Despite intensive research effort in non-osteichthyes vertebrates such as cartilaginous fish and lamprey, the molecular phylogeny of the NHR family has not been fully understood. In the present study, we focused on the inshore hagfish (Eptatretus burgeri), another group of cyclostomes, and Arctic lamprey (Lethenteron camtschaticum) for comparison. Two putative NHR homologs, which were previously identified only in silico, were cloned from the hagfish and designated as ebV1R and ebV2R. In vitro, ebV1R, as well as two out of five Arctic lamprey NHRs, increased intracellular Ca2+ in response to exogenous neurohypophysial hormones. None of the examined cyclostome NHRs altered intracellular cAMP levels. Transcripts of ebV1R were detected in multiple tissues including the brain and gill, with intense hybridization signals in the hypothalamus and adenohypophysis, while ebV2R was predominantly expressed in the systemic heart. Similarly, Arctic lamprey NHRs showed distinct expression patterns, underscoring the multifunctionality of VT in the cyclostomes as in the gnathostomes. These results and exhaustive gene synteny comparisons provide new insights into the molecular and functional evolution of the neurohypophysial hormone system in vertebrates.
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Affiliation(s)
- Yoko Yamaguchi
- Institute of Agricultural and Life Sciences, Academic Assembly, Shimane University, 1060 Nishikawatsu, Matsue, Shimane 690-8504, Japan.
| | - Wataru Takagi
- Laboratory of Physiology, Atmosphere and Ocean Research Institute, University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, Chiba 277-8564, Japan
| | - Hiroyuki Kaiya
- Department of Biochemistry, National Cerebral and Cardiovascular Center Research Institute, 6-1 Kishibe-shinmachi, Suita, Osaka 564-8565, Japan; Grandsoul Research Institute for Immunology, Inc., Matsui 8-1 Utano, Uda, Nara 633-2221, Japan
| | - Norifumi Konno
- Department of Biological Science, Graduate School of Science and Engineering, University of Toyama, 3190 Gofuku, Toyama 930-8555, Japan
| | - Masa-Aki Yoshida
- Institute of Agricultural and Life Sciences, Academic Assembly, Shimane University, 1060 Nishikawatsu, Matsue, Shimane 690-8504, Japan; Marine Biological Science Section, Education and Research Center for Biological Resources, Faculty of Life and Environmental Science, Shimane University, 194 Kamo, Okinoshima, Oki, Shimane 685-0024, Japan
| | - Shigehiro Kuraku
- Molecular Life History Laboratory, Department of Genomics and Evolutionary Biology, National Institution of Genetics, 1111 Yata, Mishima, Shizuoka 411-8540, Japan; Department of Genetics, Sokendai (Graduate University for Advanced Studies), 1111 Yata, Mishima, Shizuoka 411-8540, Japan; Laboratory for Phyloinformatics, RIKEN Center for Biosystems Dynamics Research, 2-2-3 Minatojimaminami-machi, Chuo-ku, Kobe 650-0047, Japan
| | - Susumu Hyodo
- Laboratory of Physiology, Atmosphere and Ocean Research Institute, University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, Chiba 277-8564, Japan
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Akat E, Yenmiş M, Pombal MA, Molist P, Megías M, Arman S, Veselỳ M, Anderson R, Ayaz D. Comparison of Vertebrate Skin Structure at Class Level: A Review. Anat Rec (Hoboken) 2022; 305:3543-3608. [DOI: 10.1002/ar.24908] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2021] [Revised: 02/14/2022] [Accepted: 02/21/2022] [Indexed: 11/09/2022]
Affiliation(s)
- Esra Akat
- Ege University, Faculty of Science, Biology Department Bornova, İzmir Turkey
| | - Melodi Yenmiş
- Ege University, Faculty of Science, Biology Department Bornova, İzmir Turkey
| | - Manuel A. Pombal
- Universidade de Vigo, Departamento de Bioloxía Funcional e Ciencias da Saúde, Facultade de Bioloxía‐IBIV Vigo, España
| | - Pilar Molist
- Universidade de Vigo, Departamento de Bioloxía Funcional e Ciencias da Saúde, Facultade de Bioloxía‐IBIV Vigo, España
| | - Manuel Megías
- Universidade de Vigo, Departamento de Bioloxía Funcional e Ciencias da Saúde, Facultade de Bioloxía‐IBIV Vigo, España
| | - Sezgi Arman
- Sakarya University, Faculty of Science and Letters, Biology Department Sakarya Turkey
| | - Milan Veselỳ
- Palacky University, Faculty of Science, Department of Zoology Olomouc Czechia
| | - Rodolfo Anderson
- Departamento de Zoologia, Instituto de Biociências Universidade Estadual Paulista São Paulo Brazil
| | - Dinçer Ayaz
- Ege University, Faculty of Science, Biology Department Bornova, İzmir Turkey
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Ancient fishes and the functional evolution of the corticosteroid stress response in vertebrates. Comp Biochem Physiol A Mol Integr Physiol 2021; 260:111024. [PMID: 34237466 DOI: 10.1016/j.cbpa.2021.111024] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2021] [Revised: 06/29/2021] [Accepted: 06/30/2021] [Indexed: 12/13/2022]
Abstract
The neuroendocrine mechanism underlying stress responses in vertebrates is hypothesized to be highly conserved and evolutionarily ancient. Indeed, elements of this mechanism, from the brain to steroidogenic tissue, are present in all vertebrate groups; yet, evidence of the function and even identity of some elements of the hypothalamus-pituitary-adrenal/interrenal (HPA/I) axis is equivocal among the most basal vertebrates. The purpose of this review is to discuss the functional evolution of the HPA/I axis in vertebrates with a focus on our understanding of this neuroendocrine mechanism in the most ancient vertebrates: the agnathan (i.e., hagfish and lamprey) and chondrichthyan fishes (i.e., sharks, rays, and chimeras). A review of the current literature presents evidence of a conserved HPA/I axis in jawed vertebrates (i.e., gnathostomes); yet, available data in jawless (i.e., agnathan) and chondrichthyan fishes are limited. Neuroendocrine regulation of corticosteroidogenesis in agnathans and chondrichthyans appears to function through similar pathways as in bony fishes and tetrapods; however, key elements have yet to be identified and the involvement of melanotropins and gonadotropin-releasing hormone in the stress axis in these ancient fishes warrants further investigation. Further, the identities of physiological glucocorticoids are uncertain in hagfishes, chondrichthyans, and even coelacanths. Resolving these and other knowledge gaps in the stress response of ancient fishes will be significant for advancing knowledge of the evolutionary origins of the vertebrate stress response.
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Trudeau VL, Somoza GM. Multimodal hypothalamo-hypophysial communication in the vertebrates. Gen Comp Endocrinol 2020; 293:113475. [PMID: 32240708 DOI: 10.1016/j.ygcen.2020.113475] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/25/2019] [Revised: 03/21/2020] [Accepted: 03/28/2020] [Indexed: 12/13/2022]
Abstract
The vertebrate pituitary is arguably one of the most complex endocrine glands from the evolutionary, anatomical and functional perspectives. The pituitary plays a master role in endocrine physiology for the control of growth, metabolism, reproduction, water balance, and the stress response, among many other key processes. The synthesis and secretion of pituitary hormones are under the control of neurohormones produced by the hypothalamus. Under this conceptual framework, the communication between the hypophysiotropic brain and the pituitary gland is at the foundation of our understanding of endocrinology. The anatomy of the connections between the hypothalamus and the pituitary gland has been described in different vertebrate classes, revealing diverse modes of communication together with varying degrees of complexity. In this context, the evolution and variation in the neuronal, neurohemal, endocrine and paracrine modes will be reviewed in light of recent discoveries, and a re-evaluation of earlier observations. There appears to be three main hypothalamo-pituitary communication systems: 1. Diffusion, best exemplified by the agnathans; 2. Direct innervation of the adenohypophysis, which is most developed in teleost fish, and 3. The median eminence/portal blood vessel system, most conspicuously developed in tetrapods, showing also considerable variation between classes. Upon this basic classification, there exists various combinations possible, giving rise to taxon and species-specific, multimodal control over major physiological processes. Intrapituitary paracrine regulation and communication between folliculostellate cells and endocrine cells are additional processes of major importance. Thus, a more complex evolutionary picture of hypothalamo-hypophysial communication is emerging. There is currently little direct evidence to suggest which neuroendocrine genes may control the evolution of one communication system versus another. However, studies at the developmental and intergenerational timescales implicate several genes in the angiogenesis and axonal guidance pathways that may be important.
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Affiliation(s)
- Vance L Trudeau
- Department of Biology, University of Ottawa, Ottawa, Ontario K1N 6N5, Canada.
| | - Gustavo M Somoza
- Instituto Tecnológico de Chascomús (CONICET-UNSAM), Chascomús, Buenos Aires B7130IWA, Argentina.
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Amano M, Amiya N, Yamamoto N, Osugi T, Tsutsui K. Immunohistochemical detection of prolactin-releasing peptide2 in the brain of the inshore hagfish Eptatretus burgeri. Gen Comp Endocrinol 2019; 274:1-7. [PMID: 30571962 DOI: 10.1016/j.ygcen.2018.12.005] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/28/2018] [Revised: 11/27/2018] [Accepted: 12/16/2018] [Indexed: 01/28/2023]
Abstract
Prolactin-releasing peptide2 (PrRP2) belongs to the RFamide peptide group and is a paralog of prolactin-releasing peptide (PrRP). Recent studies demonstrated that PrRP2, but not PrRP, regulates prolactin release in teleosts. The evolutionary origin of PrRP and PrRP2 dates back to at least early vertebrates because homologs of PrRP/PrRP2 were identified in lampreys, one of the earliest branch of vertebrates class Agnatha. However, PrRP/PrRP2 remains to be identified in hagfish, another representative species of class Agnatha. Here, we examined the distribution of PrRP2 in the brain and pituitary of the inshore hagfish Eptatretus burgeri to obtain further understanding of the neuroendocrine system of PrRP2. PrRP2-immunoreactive (ir) cell bodies were detected in the infundibular nucleus of hypothalamus (HYinf). PrRP2-ir fibers were restricted around PrRP2-ir cell bodies and were not detected in the dorsal wall of the neurohypophysis compared to the abundant PrRP2-ir fiber distribution in the brain and innervation to the pituitary in other vertebrates. To examine possible reciprocal connections of PrRP2 and other neuropeptides, we further conducted dual-label immunohistochemistry of PrRP2 and the PQRFamide (PQRFa) peptide or corticotropin-releasing hormone (CRH). Reciprocal connections are suggested between PrRP2 and PQRFa neurons as well as between PrRP2 and CRH neurons. The present study demonstrates, for the first time, that PrRP2 is expressed in the brain of inshore hagfish. The restricted distribution of PrRP2-ir fibers in the HYinf suggests that PrRP2 does not directly regulate the pituitary gland, but regulates the function of the HYinf where PQRFa and CRH are expressed.
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Affiliation(s)
- Masafumi Amano
- School of Marine Biosciences, Kitasato University, Sagamihara, Kanagawa 252-0373, Japan.
| | - Noriko Amiya
- School of Marine Biosciences, Kitasato University, Sagamihara, Kanagawa 252-0373, Japan
| | - Naoyuki Yamamoto
- Laboratory of Fish Biology, Graduate School of Bioagricultural Sciences, Nagoya University, Nagoya, Aichi 464-8601, Japan
| | - Tomohiro Osugi
- Laboratory of Integrative Brain Sciences, Department of Biology and Center for Medical Life Science, Waseda University, Tokyo 162-8480, Japan
| | - 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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Amano M, Amiya N, Yokoyama T, Onikubo K, Yamamoto N, Takahashi A. Immunohistochemical detection of corticotropin-releasing hormone (CRH) in the brain and pituitary of the hagfish, Eptatretus burgeri. Gen Comp Endocrinol 2016; 236:174-180. [PMID: 27444128 DOI: 10.1016/j.ygcen.2016.07.018] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/06/2016] [Revised: 06/21/2016] [Accepted: 07/16/2016] [Indexed: 10/21/2022]
Abstract
The distribution of corticotropin-releasing hormone (CRH) in the brain and pituitary of the hagfish Eptatretus burgeri, representing the earliest branch of vertebrates, was examined by immunohistochemistry to better understand the neuroendocrine system of hagfish. CRH-immunoreactive (ir) cell bodies were detected in the preoptic nucleus, periventricular preoptic nucleus, infundibular nucleus of the hypothalamus, and in the nucleus "A" of Kusunoki et al. (1982) in the medulla oblongata. In the brain, CRH-ir fibers were detected in almost all areas except for the olfactory bulb and telencephalon. Bundles of CRH-ir fibers were detected in the dorsal wall of the neurohypophysis. However, CRH-ir fibers were distant from adrenocorticotropic hormone (ACTH) cells in the adenohypophysis, as studied by dual-label immunohistochemistry. Cortisol and corticosterone were detected in the plasma by a combination of reverse-phase high performance liquid chromatography and a time-resolved fluoroimmunoassay. These results suggest that in the hagfish, CRH, ACTH, and corticosteroids exist and that CRH released in the neurohypophysis likely reaches the adenohypophysis via diffusion.
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Affiliation(s)
- Masafumi Amano
- School of Marine Biosciences, Kitasato University, Sagamihara, Kanagawa 252-0373, Japan.
| | - Noriko Amiya
- School of Marine Biosciences, Kitasato University, Sagamihara, Kanagawa 252-0373, Japan
| | - Takehiko Yokoyama
- School of Marine Biosciences, Kitasato University, Sagamihara, Kanagawa 252-0373, Japan
| | - Kengo Onikubo
- School of Marine Biosciences, Kitasato University, Sagamihara, Kanagawa 252-0373, Japan
| | - Naoyuki Yamamoto
- Laboratory of Fish Biology, Graduate School of Bioagricultural Sciences, Nagoya University, Nagoya, Aichi 464-8601, Japan
| | - Akiyoshi Takahashi
- School of Marine Biosciences, Kitasato University, Sagamihara, Kanagawa 252-0373, Japan
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de Jesus LWO, Chehade C, Costa FG, Borella MI. Pituitary gland morphogenesis and ontogeny of adenohypophyseal cells of Salminus brasiliensis (Teleostei, Characiformes). FISH PHYSIOLOGY AND BIOCHEMISTRY 2014; 40:897-909. [PMID: 24310491 DOI: 10.1007/s10695-013-9895-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/10/2013] [Accepted: 11/22/2013] [Indexed: 06/02/2023]
Abstract
In this study, we describe for the first time the details of the pituitary gland morphogenesis and the ontogeny of adenohypophyseal cells of a South American Characiform species with great importance for Brazilian Aquaculture, Salminus brasiliensis (Characiformes, Characidae), from hatching to 25 days after hatching (dah), by histochemical and immunocytochemical methods. The pituitary placode was first detected at hatching (0 dah), and the pituitary anlage became more defined at 0.5 dah. The neurohypophysis (NH) development started at 3 dah, and the early formation of its stalk at 12.5 dah. An increase in adenohypophyseal and NH tissues was also observed, and in juveniles at 25 dah, the pituitary displayed similar morphology to that found in adults of this species, displaying the main features of the teleost pituitary. PRL cells were detected at 0.5 dah, together with ACTH and α-MSH cells, followed by GH and SL cells at 1.5 dah. β-FSH cells were detected at 25 dah, while β-LH cells at 5 dah. The pituitary development in this species comprises a dynamic process similar to other teleosts. Our findings in S. brasiliensis corroborate the heterogeneity in the ontogeny of adenohypophyseal cells in teleosts and suggest a role for adenohypophyseal hormones in the early development of this species.
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Affiliation(s)
- Lázaro Wender Oliveira de Jesus
- Departamento de Biologia Celular e do Desenvolvimento, Instituto de Ciências Biomédicas, Universidade de São Paulo, Av. Professor Lineu Prestes 1524, São Paulo, SP, 05508-000, Brazil
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Nozaki M. Hypothalamic-pituitary-gonadal endocrine system in the hagfish. Front Endocrinol (Lausanne) 2013; 4:200. [PMID: 24416029 PMCID: PMC3874551 DOI: 10.3389/fendo.2013.00200] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/26/2013] [Accepted: 12/17/2013] [Indexed: 11/26/2022] Open
Abstract
The hypothalamic-pituitary system is considered to be a seminal event that emerged prior to or during the differentiation of the ancestral agnathans (jawless vertebrates). Hagfishes as one of the only two extant members of the class of agnathans are considered the most primitive vertebrates known, living or extinct. Accordingly, studies on their reproduction are important for understanding the evolution and phylogenetic aspects of the vertebrate reproductive endocrine system. In gnathostomes (jawed vertebrates), the hormones of the hypothalamus and pituitary have been extensively studied and shown to have well-defined roles in the control of reproduction. In hagfish, it was thought that they did not have the same neuroendocrine control of reproduction as gnathostomes, since it was not clear whether the hagfish pituitary gland contained tropic hormones of any kind. This review highlights the recent findings of the hypothalamic-pituitary-gonadal endocrine system in the hagfish. In contrast to gnathostomes that have two gonadotropins (GTH: luteinizing hormone and follicle-stimulating hormone), only one pituitary GTH has been identified in the hagfish. Immunohistochemical and functional studies confirmed that this hagfish GTH was significantly correlated with the developmental stages of the gonads and showed the presence of a steroid (estradiol) feedback system at the hypothalamic-pituitary levels. Moreover, while the identity of hypothalamic gonadotropin-releasing hormone (GnRH) has not been determined, immunoreactive (ir) GnRH has been shown in the hagfish brain including seasonal changes of ir-GnRH corresponding to gonadal reproductive stages. In addition, a hagfish PQRFamide peptide was identified and shown to stimulate the expression of hagfish GTHβ mRNA in the hagfish pituitary. These findings provide evidence that there are neuroendocrine-pituitary hormones that share common structure and functional features compared to later evolved vertebrates.
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Affiliation(s)
- Masumi Nozaki
- Sado Marine Biological Station, Faculty of Science, Niigata University, Sado, Japan
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Osugi T, Uchida K, Nozaki M, Tsutsui K. Characterization of novel RFamide peptides in the central nervous system of the brown hagfish: isolation, localization, and functional analysis. Endocrinology 2011; 152:4252-64. [PMID: 21862614 DOI: 10.1210/en.2011-1375] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
RFamide (RFa) peptides play various important roles in the central nervous system in both invertebrates and vertebrates. However, there is no evidence of the existence of any RFamide peptide in the brain of hagfish, one of the oldest lineages of vertebrates. In this study, we sought to identify novel RFamide peptides from the brains of hagfish (Paramyxine atami). We identified four novel RFamide peptides, which had the C-terminal Pro-Gln-Arg-Phe-NH2 structure. cDNA cloning revealed that the identified RFamide peptides are encoded in two types of cDNA. Molecular phylogenetic analysis of the two precursors indicated that the hagfish RFamide peptides belong to the PQRFamide peptide group that includes mammalian neuropeptide FF and AF. Based on immunohistochemistry and in situ hybridization, hagfish PQRFamide peptide precursor mRNA and its translated peptides were localized in the infundibular nucleus of the hypothalamus. Immunoreactive fibers were terminated on blood vessels in the infundibular nucleus. Dense immunoreactive fibers were also observed in other brain regions. We further showed that one of the hagfish PQRFamide peptides significantly stimulated the expression of gonadotropin-β mRNA in the cultured hagfish pituitary. These results indicate that the control mechanism of gonadotropin expression by a hypothalamic neuropeptide evolved in the agnathan brain. This is the first evidence describing the identification of RFamide peptides in the hagfish brain. This is also the first report showing the regulation of gonadotropin expression by a homolog of neuropeptide FF that belongs to the PQRFamide peptide group in any vertebrate.
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Affiliation(s)
- Tomohiro Osugi
- Laboratory of Integrative Brain Sciences, Department of Biology, Waseda University, Center for Medical Life Science of Waseda University, 2-2 Wakamatsu-cho, Shinjuku-.ku, Tokyo 162-8480, Japan
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Roch GJ, Busby ER, Sherwood NM. Evolution of GnRH: diving deeper. Gen Comp Endocrinol 2011; 171:1-16. [PMID: 21185290 DOI: 10.1016/j.ygcen.2010.12.014] [Citation(s) in RCA: 164] [Impact Index Per Article: 12.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/05/2010] [Revised: 12/08/2010] [Accepted: 12/10/2010] [Indexed: 12/18/2022]
Abstract
Gonadotropin-releasing hormone (GnRH) plays a central role in vertebrate reproduction. The evolutionary origin of this neuropeptide and its receptor is not obvious, but the advent of genomics makes it possible to examine the roots of GnRH and delve deeper into its ancestral relationships. New peptide sequences identified in invertebrates from annelids to tunicates reveal GnRH-like peptides of 10-12 amino acids. Structural conservation suggests homology between the 15 known invertebrate peptides and the 15 known vertebrate GnRHs. The functions of the invertebrate GnRH-like peptides are not necessarily related to reproduction. We suggest that structurally related families of invertebrate peptides including corazonin and adipokinetic hormone (AKH) form a superfamily of neuropeptides with the GnRH family. GnRH receptors have also been identified in invertebrates from annelids to tunicates suggesting that the origin of GnRH and its receptor extends deep in evolution to the origin of bilaterian animals. To resolve the relationship of invertebrate and vertebrate receptors, we conducted large-scale phylogenetic analysis using maximum likelihood. The data support a superfamily that includes GnRH, AKH and corazonin receptors derived from both published sequences and unpublished gene model predictions. Closely related to the GnRHR superfamily is the vasopressin/oxytocin superfamily of receptors. Phylogenetic analysis suggests a shared ancestry with deep roots. A functional role for GnRH in vertebrates or invertebrates leads to questions about the evolutionary origin of the pituitary. Our analysis suggests a functioning pituitary was the result of genomic duplications in early vertebrates.
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Affiliation(s)
- Graeme J Roch
- Department of Biology, University of Victoria, Victoria, BC, Canada V8W 3N5
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Borella MI, Venturieri R, Mancera JM. Immunocytochemical identification of adenohypophyseal cells in the pirarucu (Arapaima gigas), an Amazonian basal teleost. FISH PHYSIOLOGY AND BIOCHEMISTRY 2009; 35:3-16. [PMID: 18758983 DOI: 10.1007/s10695-008-9254-x] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/22/2008] [Accepted: 07/25/2008] [Indexed: 05/26/2023]
Abstract
The adenohypophysis (AH) of juvenile pirarucu (Arapaima gigas), a representative species of the Osteoglossomorpha (bonytongue fishes, one of the oldest living groups of the teleosts), was studied using histochemical and immunocytochemical methods. The AH is comprised of the pars distalis (PD), without a clear distinction between rostral pars distalis (RPD) and proximal pars distalis (PPD), and the pars intermedia (PI). The neurohypophysis (NH) is positioned on top of the PD and penetrates and branches into the PI. In the most rostral dorsal portion of the PD, adrenocorticotropic cells and fusiform gonadotropic cells were found. In the central PD, scarce prolactin-producing cells and growth-hormone-producing cells were located mainly in the dorsal part, whereas round gonadotropic cells were abundant in the ventral portion of this region. Human thyrotropin immunoreactive cells were not found in the entire AH. In the PI, melanotropic, some adrenocorticotropic, and somatolactin-producing cells were located intermingled surrounding the neurohypophyseal branches. Our results showed that the A. gigas pituitary has some basal characteristics between the ancient Actinopterygii and the more derived teleosts.
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Affiliation(s)
- M I Borella
- Departamento de Biologia Celular e do Desenvolvimento, Instituto de Ciências Biomédicas, Universidade de São Paulo, Sao Paulo, Brazil.
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Nozaki M. The Hagfish Pituitary Gland and Its Putative Adenohypophysial Hormones. Zoolog Sci 2008; 25:1028-36. [DOI: 10.2108/zsj.25.1028] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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13
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Nozaki M, Shimotani T, Uchida K. Gonadotropin-like and adrenocorticotropin-like cells in the pituitary gland of hagfish, Paramyxine atami; immunohistochemistry in combination with lectin histochemistry. Cell Tissue Res 2007; 328:563-72. [PMID: 17347815 DOI: 10.1007/s00441-006-0349-3] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2006] [Accepted: 09/19/2006] [Indexed: 10/23/2022]
Abstract
The pituitary system of the hagfish remains an enigma. The present study has aimed to detect possible adenohypophysial hormones in the pituitary gland of the brown hagfish, Paramyxine atami, by means of immunohistochemistry in combination with lectin histochemistry. Rabbit antisera raised against ovine luteinizing hormone (LH)beta, proopiomelanocortin (POMC)-related peptides, and the growth hormone/prolactin family of tetrapod and fish species were used, and 25 kinds of lectins were tested. Three different types of adenohypophysial cells were revealed in the pituitary of brown hagfish. The first was stained with both anti-ovine LH beta and several D-mannose-binding lectins, such as Lens culinaris agglutinin and Pisum sativum agglutinin. This cell type predominated in the adenohypophysis in adults with developing gonads and thus appeared to be involved in the regulation of gonadal functions. The second was negative for anti-ovine LH beta but was stained with several N-acetylglucosamine-binding lectins, such as wheat germ agglutinin and Lycopersicon esculentum lectin. This cell type exhibited a weak positive reaction with anti-lamprey adrenocorticotropin (ACTH) and thus appeared to be related to POMC-like cells. The second cell type was found in the adenohypophysis regardless of the developmental state of the gonads. The third cell type was negative for both antisera and lectins. Since this cell type was numerous in juveniles and adults without developing gonads, most cells of this type were probably undifferentiated. These findings suggest that GTH and ACTH are major adenohypophysial hormones in the hagfish.
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Affiliation(s)
- Masumi Nozaki
- Sado Marine Biological Station, Faculty of Science, Niigata University, Tassha, Sado, Niigata, 952-2135, Japan.
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Peripheral Endocrine Glands. II. The Adrenal Glands and the Corpuscles of Stannius. ACTA ACUST UNITED AC 2007. [DOI: 10.1016/s1546-5098(07)26009-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register]
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Youson JH. Peripheral Endocrine Glands. I. The Gastroenteropancreatic Endocrine System and the Thyroid Gland. FISH PHYSIOLOGY 2007. [DOI: 10.1016/s1546-5098(07)26008-x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/11/2023]
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Miki M, Shimotani T, Uchida K, Hirano S, Nozaki M. Immunohistochemical detection of gonadotropin-like material in the pituitary of brown hagfish (Paramyxine atami) correlated with their gonadal functions and effect of estrogen treatment. Gen Comp Endocrinol 2006; 148:15-21. [PMID: 16574116 DOI: 10.1016/j.ygcen.2006.01.018] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/16/2005] [Revised: 01/03/2006] [Accepted: 01/05/2006] [Indexed: 11/16/2022]
Abstract
Since hagfish are members of the most primitive group of living vertebrates, studies on their reproduction are indispensable for understanding phylogenetic aspects of vertebrate reproductive system. Nevertheless, our knowledge of the reproductive physiology of the hagfish, especially of the pituitary-gonadal axis, is almost completely lacking. In the present study, the relationship between the amount of immunoreactive gonadotropin (GTH)-like material in the pituitary gland and gonadal conditions was examined in the brown hagfish, Paramyxine atami. First, pituitary sections were stained immunohistochemically with anti-ovine LHbeta, and the degrees of the accumulation of GTH-like material were compared among three different groups of gonadal conditions; juveniles and adults with and without developing gonads. Immunoreactive GTH-like material was heavily accumulated in adults with developing gonads, whereas it was not or only weakly accumulated in juveniles or adults without developing gonads. Thus, there was a strong positive correlation between the amount of GTH-like material and gonadal conditions. Second, effect of estradiol benzoate on GTH-like material was examined using three groups of juvenile hagfish: initial control, sham control, and experimental animals. Experimental animals received estradiol benzoate resolved in sesame oil intraperitoneally every third day for 1 month, whereas sham control animals received the same doses of sesame oil. GTH-like material was heavily or moderately accumulated in most estrogen-treated animals, whereas it was not or weakly accumulated in initial or sham control animals. Thus, estrogen treatment in juvenile hagfish resulted in the large increase in the amount of GTH-like material. From these results, it is suggested the presence of not only GTH but also the hypophysial-gonadal feedback system in the hagfish.
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Affiliation(s)
- Makoto Miki
- Sado Marine Biological Station, Faculty of Science, Niigata University, Tassha, Sado, Niigata 952-2135, Japan
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