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Zupa R, Duncan N, Giménez I, Mylonas CC, Pousis C, Passantino L, Cuko R, Corriero A. Male germ cell proliferation and apoptosis in sexually immature meagre Argyrosomus regius (Asso, 1801) treated with recombinant follicle stimulating hormone. Sci Rep 2023; 13:7013. [PMID: 37117257 PMCID: PMC10147655 DOI: 10.1038/s41598-023-34102-1] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2022] [Accepted: 04/24/2023] [Indexed: 04/30/2023] Open
Abstract
The meagre Argyrosomus regius (Asso, 1801) is a marine fish species that has an increasing aquaculture production in Europe. Lowering the age at maturity of hatchery-produced juveniles would support meagre aquaculture by reducing time between generations in selective breeding programs and reducing industrial costs for broodstock maintenance. The aim of this work was to assess the effects of a treatment with recombinant follicle stimulating hormone (rFsh), produced in ovarian cells of Chinese hamsters, on male germ cell proliferation and apoptosis in sexually immature meagre. The rFsh-treated fish had higher gonadosomatic index, larger seminiferous tubules, more abundant luminal spermatozoa, a lower density of anti-PCNA positive single A spermatogonia, a higher density of anti-PCNA positive spermatocysts and a lower incidence of germ cell apoptosis than control groups. The present study demonstrated the effectiveness of the produced rFsh in stimulating testis development and spermatogenesis in pre-pubertal meagre. Moreover, the rFsh treatment proved to be highly efficient in removing the apoptotic block of spermatogenesis observed in juvenile meagre, allowing spermatogonial survival and progress towards meiosis. The administration of rFsh did not stimulate spermatogonial self-renewal, a process whose control still needs to be elucidated.
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Affiliation(s)
- Rosa Zupa
- Department of Veterinary Medicine, University of Bari Aldo Moro, S.P. per Casamassima km.3, 70010, Valenzano, Bari, Italy
| | - Neil Duncan
- IRTA, Ctra. de Poble Nou km. 5.5, 43540, La Ràpita, Tarragona, Spain
| | - Ignacio Giménez
- Rara Avis Biotec, S. L., Calle Moratín 17, 46002, Valencia, Spain
| | - Constantinos C Mylonas
- Institute of Marine Biology, Biotechnology and Aquaculture, Hellenic Centre for Marine Research, 71003, Heraklion, Crete, Greece
| | - Chrysovalentinos Pousis
- Department of Veterinary Medicine, University of Bari Aldo Moro, S.P. per Casamassima km.3, 70010, Valenzano, Bari, Italy
| | - Letizia Passantino
- DiMePRe-J, University of Bari Aldo Moro, S.P. per Casamassima km.3, 70010, Valenzano, Bari, Italy
| | - Rezart Cuko
- Department of Veterinary Medicine, University of Bari Aldo Moro, S.P. per Casamassima km.3, 70010, Valenzano, Bari, Italy
| | - Aldo Corriero
- Department of Veterinary Medicine, University of Bari Aldo Moro, S.P. per Casamassima km.3, 70010, Valenzano, Bari, Italy.
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2
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Vissio PG, Di Yorio MP, Pérez-Sirkin DI, Somoza GM, Tsutsui K, Sallemi JE. Developmental aspects of the hypothalamic-pituitary network related to reproduction in teleost fish. Front Neuroendocrinol 2021; 63:100948. [PMID: 34678303 DOI: 10.1016/j.yfrne.2021.100948] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/15/2021] [Revised: 08/27/2021] [Accepted: 10/04/2021] [Indexed: 12/11/2022]
Abstract
The hypothalamic-pituitary-gonadal axis is the main system that regulates reproduction in vertebrates through a complex network that involves different neuropeptides, neurotransmitters, and pituitary hormones. Considering that this axis is established early on life, the main goal of the present work is to gather information on its development and the actions of its components during early life stages. This review focuses on fish because their neuroanatomical characteristics make them excellent models to study neuroendocrine systems. The following points are discussed: i) developmental functions of the neuroendocrine components of this network, and ii) developmental disruptions that may impact adult reproduction. The importance of the components of this network and their susceptibility to external/internal signals that can alter their specific early functions and/or even the establishment of the reproductive axis, indicate that more studies are necessary to understand this complex and dynamic network.
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Affiliation(s)
- Paula G Vissio
- Universidad de Buenos Aires, Facultad de Ciencias Exactas y Naturales, Departamento de Biodiversidad y Biología Experimental, Buenos Aires, Argentina; CONICET - Universidad de Buenos Aires, Instituto de Biodiversidad y Biología Experimental y Aplicada (IBBEA), CONICET, Buenos Aires, Argentina.
| | - María P Di Yorio
- Universidad de Buenos Aires, Facultad de Ciencias Exactas y Naturales, Departamento de Biodiversidad y Biología Experimental, Buenos Aires, Argentina; CONICET - Universidad de Buenos Aires, Instituto de Biodiversidad y Biología Experimental y Aplicada (IBBEA), CONICET, Buenos Aires, Argentina
| | - Daniela I Pérez-Sirkin
- Universidad de Buenos Aires, Facultad de Ciencias Exactas y Naturales, Departamento de Biodiversidad y Biología Experimental, Buenos Aires, Argentina; CONICET - Universidad de Buenos Aires, Instituto de Biodiversidad y Biología Experimental y Aplicada (IBBEA), CONICET, Buenos Aires, Argentina
| | - Gustavo M Somoza
- Instituto Tecnológico de Chascomús (CONICET-UNSAM), Chascomús, Argentina
| | - 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
| | - Julieta E Sallemi
- Universidad de Buenos Aires, Facultad de Ciencias Exactas y Naturales, Departamento de Biodiversidad y Biología Experimental, Buenos Aires, Argentina; CONICET - Universidad de Buenos Aires, Instituto de Biodiversidad y Biología Experimental y Aplicada (IBBEA), CONICET, Buenos Aires, Argentina
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3
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Fontaine R, Royan MR, von Krogh K, Weltzien FA, Baker DM. Direct and Indirect Effects of Sex Steroids on Gonadotrope Cell Plasticity in the Teleost Fish Pituitary. Front Endocrinol (Lausanne) 2020; 11:605068. [PMID: 33365013 PMCID: PMC7750530 DOI: 10.3389/fendo.2020.605068] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/11/2020] [Accepted: 10/12/2020] [Indexed: 12/26/2022] Open
Abstract
The pituitary gland controls many important physiological processes in vertebrates, including growth, homeostasis, and reproduction. As in mammals, the teleost pituitary exhibits a high degree of plasticity. This plasticity permits changes in hormone production and secretion necessary to meet the fluctuating demands over the life of an animal. Pituitary plasticity is achieved at both cellular and population levels. At the cellular level, hormone synthesis and release can be regulated via changes in cell composition to modulate both sensitivity and response to different signals. At the cell population level, the number of cells producing a given hormone can change due to proliferation, differentiation of progenitor cells, or transdifferentiation of specific cell types. Gonadotropes, which play an important role in the control of reproduction, have been intensively investigated during the last decades and found to display plasticity. To ensure appropriate endocrine function, gonadotropes rely on external and internal signals integrated at the brain level or by the gonadotropes themselves. One important group of internal signals is the sex steroids, produced mainly by the gonadal steroidogenic cells. Sex steroids have been shown to exert complex effects on the teleost pituitary, with differential effects depending on the species investigated, physiological status or sex of the animal, and dose or method of administration. This review summarizes current knowledge of the effects of sex steroids (androgens and estrogens) on gonadotrope cell plasticity in teleost anterior pituitary, discriminating direct from indirect effects.
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Affiliation(s)
- Romain Fontaine
- Physiology Unit, Faculty of Veterinary Medicine, Norwegian University of Life Sciences, Oslo, Norway
| | - Muhammad Rahmad Royan
- Physiology Unit, Faculty of Veterinary Medicine, Norwegian University of Life Sciences, Oslo, Norway
| | - Kristine von Krogh
- Physiology Unit, Faculty of Veterinary Medicine, Norwegian University of Life Sciences, Oslo, Norway
| | - Finn-Arne Weltzien
- Physiology Unit, Faculty of Veterinary Medicine, Norwegian University of Life Sciences, Oslo, Norway
| | - Dianne M. Baker
- Department of Biological Sciences, University of Mary Washington, Fredericksburg, VA, United States
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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: 8] [Impact Index Per Article: 1.6] [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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5
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Wylie MJ, Setiawan AN, Irvine GW, Symonds JE, Elizur A, Lokman PM. Effects of neuropeptides and sex steroids on the pituitary-gonadal axis of pre-pubertal F1 wreckfish (hāpuku) Polyprion oxygeneios in vivo: Evidence of inhibitory effects of androgens. Gen Comp Endocrinol 2018; 257:113-121. [PMID: 28822774 DOI: 10.1016/j.ygcen.2017.08.018] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/15/2017] [Revised: 08/08/2017] [Accepted: 08/15/2017] [Indexed: 11/26/2022]
Abstract
The ability to advance puberty in broodstock that have a long generation interval and mature at large size is a highly valuable tool in contemporary aquaculture enterprise. Juvenile male and female wreckfish 'hāpuku' (Polyprion oxygeneios), a candidate for commercialization in aquaculture, were subjected to treatment for 8weeks with two implants, one containing steroid (blank; estradiol-17β, E2; 11-ketotestosterone, KT; 17 α-methyltestosterone, MT), the other peptide (blank; gonadotropin-releasing hormone analog, GnRHa; kisspeptin, Kiss2-12). The expression of target genes (glycoprotein homone α-subunit, gpa; follicle stimulating-hormone β-subunit, fshb; luteinizing hormone β-subunit, lhb; GnRH receptor, gnrhr) in the pituitary was assayed by quantitative PCR. KT and MT decreased mRNA levels of all target genes in both male and female hāpuku, suggestive of a strong inhibitory tone by these steroid hormones. E2, GnRHa and Kiss2-12 were largely ineffective, regardless of whether they were administered alone or in combination with steroid implants. Clear differences in release and/or clearance rates between E2 and KT from implants were evident, in part explaining our observations. Advancement of puberty was not achieved, and we pose that different hormone doses and/or administration during more advanced stages of gonadogenesis need to be considered to move this field forward.
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Affiliation(s)
- Matthew J Wylie
- Department of Zoology, University of Otago, PO Box 56, Dunedin 9054, New Zealand.
| | - Alvin N Setiawan
- National Institute of Water and Atmospheric Research, Northland Marine Research Centre, PO Box 147, Ruakaka 0151, New Zealand
| | - Glen W Irvine
- National Institute of Water and Atmospheric Research, Northland Marine Research Centre, PO Box 147, Ruakaka 0151, New Zealand
| | - Jane E Symonds
- National Institute of Water and Atmospheric Research, Northland Marine Research Centre, PO Box 147, Ruakaka 0151, New Zealand
| | - Abigail Elizur
- Faculty of Science, Health, Education and Engineering, GeneCology Research Centre, University of the Sunshine Coast, Sunshine Coast, Queensland, Australia
| | - P Mark Lokman
- Department of Zoology, University of Otago, PO Box 56, Dunedin 9054, New Zealand
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6
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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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7
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von Krogh K, Bjørndal GT, Nourizadeh-Lillabadi R, Hodne K, Ropstad E, Haug TM, Weltzien FA. Sex steroids differentially regulate fshb, lhb and gnrhr expression in Atlantic cod ( Gadus morhua). Reproduction 2017; 154:581-594. [PMID: 28780570 DOI: 10.1530/rep-17-0208] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2017] [Revised: 07/23/2017] [Accepted: 07/31/2017] [Indexed: 01/03/2023]
Abstract
Depending on the stage of gonad maturation, as well as other factors, gonadal steroids can exert either a positive or negative feedback at the brain and pituitary level. While this has been demonstrated in many teleost species, little is known about the nature of steroid feedback in Gadiform fish. Using an optimized in vitro model system of the Atlantic cod pituitary, the present study investigated the potential effects of two physiologically relevant doses of estradiol, testosterone (TS) or dihydrotestosterone (DHTS) on cell viability and gene expression of gonadotropin subunits (fshb/lhb) and two suggested reproduction-relevant gonadotropin-releasing hormone receptors (gnrhr1b/gnrhr2a) during three stages of sexual maturity. In general, all steroids stimulated cell viability in terms of metabolic activity and membrane integrity. Furthermore, all steroids affected fshb expression, with the effect depending on both the specific steroid, dose and maturity status. Conversely, only DHTS exposure affected lhb levels, and this occurred only during the spawning season. Using single-cell qPCR, co-transcription of gnrhr1b and gnrhr2a was confirmed to both fshb- and lhb- expressing gonadotropes, with gnrhr2a being the most prominently expressed isoform. While steroid exposure had no effect on gnrhr1b expression, all steroids affected gnrhr2a transcript levels in at least one maturity stage. These and previous results from our group point to Gnrhr2a as the main modulator of gonadotropin regulation in cod and that regulation of its gene expression level might function as a direct mechanism for steroid feedback at the pituitary level.
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Affiliation(s)
- Kristine von Krogh
- Department of Basic Sciences and Aquatic Medicine, Norwegian University of Life Sciences, Oslo, Norway
| | | | | | - Kjetil Hodne
- Department of Basic Sciences and Aquatic Medicine, Norwegian University of Life Sciences, Oslo, Norway
| | - Erik Ropstad
- Department of Production Animal Clinical Sciences, Norwegian University of Life Science, Oslo, Norway
| | - Trude M Haug
- Department of Biosciences, University of Oslo, Oslo, Norway.,Department of Oral Biology, University of Oslo, Oslo, Norway
| | - Finn-Arne Weltzien
- Department of Basic Sciences and Aquatic Medicine, Norwegian University of Life Sciences, Oslo, Norway
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Yan H. Inhibitory Control of the Brain-Pituitary Reproductive Axis of Male European Sea Bass: Role of Gonadotropin Inhibitory Hormone. Biol Reprod 2016; 94:126. [PMID: 27009042 PMCID: PMC6702785 DOI: 10.1095/biolreprod.116.140517] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/01/2022] Open
Affiliation(s)
- Hongwei Yan
- College of Fisheries and Life Science; Center for Marine Ranching Engineering Science Research of Liaoning, Dalian Ocean University, Dalian, China
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9
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Paullada-Salmerón JA, Cowan M, Aliaga-Guerrero M, Morano F, Zanuy S, Muñoz-Cueto JA. Gonadotropin Inhibitory Hormone Down-Regulates the Brain-Pituitary Reproductive Axis of Male European Sea Bass (Dicentrarchus labrax). Biol Reprod 2016; 94:121. [PMID: 26984999 PMCID: PMC6322450 DOI: 10.1095/biolreprod.116.139022] [Citation(s) in RCA: 42] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2016] [Accepted: 03/08/2016] [Indexed: 01/17/2023] Open
Abstract
Gonadotropin-inhibitory hormone (GnIH) inhibits gonadotropin synthesis and release from the pituitary of birds and mammals. However, the physiological role of orthologous GnIH peptides on the reproductive axis of fish is still uncertain, and their actions on the main neuroendocrine systems controlling reproduction (i.e., GnRHs, kisspeptins) have received little attention. In a recent study performed in the European sea bass, we cloned a cDNA encoding a precursor polypeptide that contained C-terminal MPMRFamide (sbGnIH-1) and MPQRFamide (sbGnIH-2) peptide sequences, developed a specific antiserum against sbGnIH-2, and characterized its central and pituitary GnIH projections in this species. In this study, we analyzed the effects of intracerebroventricular injection of sbGnIH-1 and sbGnIH-2 on brain and pituitary expression of reproductive hormone genes (gnrh1, gnrh2, gnrh3, kiss1, kiss2, gnih, lhbeta, fshbeta), and their receptors (gnrhr II-1a, gnrhr II-2b, kiss1r, kiss2r, and gnihr) as well as on plasma Fsh and Lh levels. In addition, we determined the effects of GnIH on pituitary somatotropin (Gh) expression. The results obtained revealed the inhibitory role of sbGnIH-2 on brain gnrh2, kiss1, kiss2, kiss1r, gnih, and gnihr transcripts and on pituitary fshbeta, lhbeta, gh, and gnrhr-II-1a expression, whereas sbGnIH-1 only down-regulated brain gnrh1 expression. However, at different doses, central administration of both sbGnIH-1 and sbGnIH-2 decreased Lh plasma levels. Our work represents the first study reporting the effects of centrally administered GnIH in fish and provides evidence of the differential actions of sbGnIH-1 and sbGnIH-2 on the reproductive axis of sea bass, the main inhibitory role being exerted by the sbGnIH-2 peptide.
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Affiliation(s)
- José A Paullada-Salmerón
- Department of Biology, Faculty of Environmental and Marine Sciences, University of Cádiz, Marine Campus of International Excellence (CEIMAR) and Agrifood Campus of International Excellence (ceiA3), Puerto Real, Spain INMAR-CACYTMAR Research Institutes, Puerto Real University Campus, Puerto Real, Spain
| | - Mairi Cowan
- Department of Biology, Faculty of Environmental and Marine Sciences, University of Cádiz, Marine Campus of International Excellence (CEIMAR) and Agrifood Campus of International Excellence (ceiA3), Puerto Real, Spain INMAR-CACYTMAR Research Institutes, Puerto Real University Campus, Puerto Real, Spain
| | - María Aliaga-Guerrero
- Department of Biology, Faculty of Environmental and Marine Sciences, University of Cádiz, Marine Campus of International Excellence (CEIMAR) and Agrifood Campus of International Excellence (ceiA3), Puerto Real, Spain INMAR-CACYTMAR Research Institutes, Puerto Real University Campus, Puerto Real, Spain
| | - Francesca Morano
- Department of Biology, Faculty of Environmental and Marine Sciences, University of Cádiz, Marine Campus of International Excellence (CEIMAR) and Agrifood Campus of International Excellence (ceiA3), Puerto Real, Spain INMAR-CACYTMAR Research Institutes, Puerto Real University Campus, Puerto Real, Spain
| | - Silvia Zanuy
- Institute of Aquaculture of Torre de la Sal, CSIC, Ribera de Cabanes, Castellón, Spain
| | - José A Muñoz-Cueto
- Department of Biology, Faculty of Environmental and Marine Sciences, University of Cádiz, Marine Campus of International Excellence (CEIMAR) and Agrifood Campus of International Excellence (ceiA3), Puerto Real, Spain INMAR-CACYTMAR Research Institutes, Puerto Real University Campus, Puerto Real, Spain
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10
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Guzmán JM, Luckenbach JA, da Silva DAM, Ylitalo GM, Swanson P. Development of approaches to induce puberty in cultured female sablefish (Anoplopoma fimbria). Gen Comp Endocrinol 2015; 221:101-13. [PMID: 25843684 DOI: 10.1016/j.ygcen.2015.02.024] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/12/2014] [Revised: 02/18/2015] [Accepted: 02/23/2015] [Indexed: 12/13/2022]
Abstract
Efforts to establish sustainable and efficient aquaculture production of sablefish (Anoplopoma fimbria) have been constrained by delayed puberty in cultured females. This study integrates a series of experiments aimed at gaining an understanding of the reproductive physiology of puberty in female sablefish. We detected transcripts for the dopamine D2 receptor (drd2) in brain, pituitary and ovary of sablefish, and prepubertal females exhibited significantly elevated brain and pituitary drd2 expression relative to wild maturing females. Treatments with sustained-release cholesterol pellets containing testosterone (T) and the dopamine D2 receptor antagonist, metoclopramide (Met), stimulated expression of pituitary luteinizing hormone beta subunit (lhb) and follicle-stimulating hormone beta subunit (fshb), respectively, in prepubertal females, whereas a combination of T and gonadotropin-releasing hormone agonist (GnRHa) had a strong synergistic effect on lhb expression (2000-fold higher than control). Although T induced a significant increase in the maximum ovarian follicle volume, none of the treatments tested stimulated onset of vitellogenesis. Using liquid chromatography/tandem mass spectrometry, we demonstrated that Met stimulated production of T by previtellogenic ovarian follicles in vitro, whereas gonadotropin preparations enhanced 17α-hydroxyprogesterone, androstenedione (A4), T and 17β-estradiol (E2) production. Treatment with T increased production of A4, 11β-hydroxyandrostenedione, 11β-hydroxytestosterone, E2, 11-ketotestosterone, and 5α-dihydrotestosterone (DHT). Interestingly, in the presence of high doses of T the previtellogenic ovary preferentially produced A4 and DHT over any other metabolite. Our data suggest the existence of dopamine inhibition of the reproductive axis in female sablefish. Treatments with Met and T elevated gonadotropin mRNAs in prepubertal females but failed to stimulate the transition into vitellogenic growth, suggesting a possible failure in pituitary gonadotropin protein synthesis/release. Previtellogenic ovarian follicles of sablefish are equipped to synthesize steroids, including those required for vitellogenic growth, and DHT, a steroid hormone whose role in reproduction of fishes remains unknown.
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Affiliation(s)
- José M Guzmán
- Environmental and Fisheries Sciences Division, Northwest Fisheries Science Center, National Oceanic and Atmospheric Administration - National Marine Fisheries Service, Seattle, WA 98112, USA.
| | - J Adam Luckenbach
- Environmental and Fisheries Sciences Division, Northwest Fisheries Science Center, National Oceanic and Atmospheric Administration - National Marine Fisheries Service, Seattle, WA 98112, USA; Center for Reproductive Biology, Washington State University, Pullman, WA 99164, USA
| | - Denis A M da Silva
- Environmental and Fisheries Sciences Division, Northwest Fisheries Science Center, National Oceanic and Atmospheric Administration - National Marine Fisheries Service, Seattle, WA 98112, USA
| | - Gina M Ylitalo
- Environmental and Fisheries Sciences Division, Northwest Fisheries Science Center, National Oceanic and Atmospheric Administration - National Marine Fisheries Service, Seattle, WA 98112, USA
| | - Penny Swanson
- Environmental and Fisheries Sciences Division, Northwest Fisheries Science Center, National Oceanic and Atmospheric Administration - National Marine Fisheries Service, Seattle, WA 98112, USA; Center for Reproductive Biology, Washington State University, Pullman, WA 99164, USA
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11
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Paullada-Salmerón JA, Cowan M, Aliaga-Guerrero M, Gómez A, Zanuy S, Mañanos E, Muñoz-Cueto JA. LPXRFa peptide system in the European sea bass: A molecular and immunohistochemical approach. J Comp Neurol 2015; 524:176-98. [DOI: 10.1002/cne.23833] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2015] [Revised: 06/17/2015] [Accepted: 06/18/2015] [Indexed: 01/15/2023]
Affiliation(s)
- José A. Paullada-Salmerón
- Department of Biology; Faculty of Environmental and Marine Sciences, University of Cádiz, Marine Campus of International Excellence (CEIMAR) and Agrifood Campus of International Excellence (ceiA3); E-11510 Puerto Real Spain
- INMAR-CACYTMAR Research Institutes, Puerto Real University Campus; E-11510 Puerto Real Spain
| | - Mairi Cowan
- Department of Biology; Faculty of Environmental and Marine Sciences, University of Cádiz, Marine Campus of International Excellence (CEIMAR) and Agrifood Campus of International Excellence (ceiA3); E-11510 Puerto Real Spain
- INMAR-CACYTMAR Research Institutes, Puerto Real University Campus; E-11510 Puerto Real Spain
| | - María Aliaga-Guerrero
- Department of Biology; Faculty of Environmental and Marine Sciences, University of Cádiz, Marine Campus of International Excellence (CEIMAR) and Agrifood Campus of International Excellence (ceiA3); E-11510 Puerto Real Spain
- INMAR-CACYTMAR Research Institutes, Puerto Real University Campus; E-11510 Puerto Real Spain
| | - Ana Gómez
- Institute of Aquaculture of Torre de la Sal, CSIC; Ribera de Cabanes E-12595 Castellón Spain
| | - Silvia Zanuy
- Institute of Aquaculture of Torre de la Sal, CSIC; Ribera de Cabanes E-12595 Castellón Spain
| | - Evaristo Mañanos
- Institute of Aquaculture of Torre de la Sal, CSIC; Ribera de Cabanes E-12595 Castellón Spain
| | - José A. Muñoz-Cueto
- Department of Biology; Faculty of Environmental and Marine Sciences, University of Cádiz, Marine Campus of International Excellence (CEIMAR) and Agrifood Campus of International Excellence (ceiA3); E-11510 Puerto Real Spain
- INMAR-CACYTMAR Research Institutes, Puerto Real University Campus; E-11510 Puerto Real Spain
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12
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Levavi-Sivan B, Bogerd J, Mañanós EL, Gómez A, Lareyre JJ. Perspectives on fish gonadotropins and their receptors. Gen Comp Endocrinol 2010; 165:412-37. [PMID: 19686749 DOI: 10.1016/j.ygcen.2009.07.019] [Citation(s) in RCA: 331] [Impact Index Per Article: 23.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/17/2009] [Revised: 07/10/2009] [Accepted: 07/16/2009] [Indexed: 12/19/2022]
Abstract
Teleosts lack a hypophyseal portal system and hence neurohormones are carried by nerve fibers from the preoptic region to the pituitary. The various cell types in the teleost pituitary are organized in discrete domains. Fish possess two gonadotropins (GtH) similar to FSH and LH in other vertebrates; they are heterodimeric hormones that consist of a common alpha subunit non-covalently associated with a hormone-specific beta subunit. In recent years the availability of molecular cloning techniques allowed the isolation of the genes coding for the GtH subunits in 56 fish species representing at least 14 teleost orders. Advanced molecular engineering provides the technology to produce recombinant GtHs from isolated cDNAs. Various expression systems have been used for the production of recombinant proteins. Recombinant fish GtHs were produced for carp, seabream, channel and African catfish, goldfish, eel, tilapia, zebrafish, Manchurian trout and Orange-spotted grouper. The hypothalamus in fishes exerts its regulation on the release of the GtHs via several neurohormones such as GnRH, dopamine, GABA, PACAP, IGF-I, norepinephrine, NPY, kisspeptin, leptin and ghrelin. In addition, gonadal steroids and peptides exert their effects on the gonadotropins either directly or via the hypothalamus. All these are discussed in detail in this review. In mammals, the biological activities of FSH and LH are directed to different gonadal target cells through the cell-specific expression of the FSH receptor (FSHR) and LH receptor (LHR), respectively, and the interaction between each gonadotropin-receptor couple is highly selective. In contrast, the bioactivity of fish gonadotropins seems to be less specific as a result of promiscuous hormone-receptor interactions, while FSHR expression in Leydig cells explains the strong steroidogenic activity of FSH in certain fish species.
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Affiliation(s)
- B Levavi-Sivan
- The Robert H. Smith Faculty of Agriculture, Food and Environment, Department of Animal Sciences, The Hebrew University of Jerusalem, Rehovot 76100, Israel.
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Taranger GL, Carrillo M, Schulz RW, Fontaine P, Zanuy S, Felip A, Weltzien FA, Dufour S, Karlsen O, Norberg B, Andersson E, Hansen T. Control of puberty in farmed fish. Gen Comp Endocrinol 2010; 165:483-515. [PMID: 19442666 DOI: 10.1016/j.ygcen.2009.05.004] [Citation(s) in RCA: 256] [Impact Index Per Article: 18.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/08/2008] [Revised: 04/17/2009] [Accepted: 05/06/2009] [Indexed: 11/30/2022]
Abstract
Puberty comprises the transition from an immature juvenile to a mature adult state of the reproductive system, i.e. the individual becomes capable of reproducing sexually for the first time, which implies functional competence of the brain-pituitary-gonad (BPG) axis. Early puberty is a major problem in many farmed fish species due to negative effects on growth performance, flesh composition, external appearance, behaviour, health, welfare and survival, as well as possible genetic impact on wild populations. Late puberty can also be a problem for broodstock management in some species, while some species completely fail to enter puberty under farming conditions. Age and size at puberty varies between and within species and strains, and are modulated by genetic and environmental factors. Puberty onset is controlled by activation of the BPG axis, and a range of internal and external factors are hypothesised to stimulate and/or modulate this activation such as growth, adiposity, feed intake, photoperiod, temperature and social factors. For example, there is a positive correlation between rapid growth and early puberty in fish. Age at puberty can be controlled by selective breeding or control of photoperiod, feeding or temperature. Monosex stocks can exploit sex dimorphic growth patterns and sterility can be achieved by triploidisation. However, all these techniques have limitations under commercial farming conditions. Further knowledge is needed on both basic and applied aspects of puberty control to refine existing methods and to develop new methods that are efficient in terms of production and acceptable in terms of fish welfare and sustainability.
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14
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Dufour S, Sebert ME, Weltzien FA, Rousseau K, Pasqualini C. Neuroendocrine control by dopamine of teleost reproduction. JOURNAL OF FISH BIOLOGY 2010; 76:129-160. [PMID: 20738703 DOI: 10.1111/j.1095-8649.2009.02499.x] [Citation(s) in RCA: 96] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
While gonadotropin-releasing hormone (GnRH) is considered as the major hypothalamic factor controlling pituitary gonadotrophins in mammals and most other vertebrates, its stimulatory actions may be opposed by the potent inhibitory actions of dopamine (DA) in teleosts. This dual neuroendocrine control of reproduction by GnRH and DA has been demonstrated in various, but not all, adult teleosts, where DA participates in an inhibitory role in the neuroendocrine regulation of the last steps of gametogenesis (final oocyte maturation and ovulation in females and spermiation in males). This has major implications for inducing spawning in aquaculture. In addition, DA may also play an inhibitory role during the early steps of gametogenesis in some teleost species, and thus interact with GnRH in the control of puberty. Various neuroanatomical investigations have shown that DA neurones responsible for the inhibitory control of reproduction originate in a specific nucleus of the preoptic area (NPOav) and project directly to the region of the pituitary where gonadotrophic cells are located. Pharmacological studies showed that the inhibitory effects of DA on pituitary gonadotrophin production are mediated by DA-D2 type receptors. DA-D2 receptors have now been sequenced in several teleosts, and the coexistence of several DA-D2 subtypes has been demonstrated in a few species. Hypophysiotropic DA activity varies with development and reproductive cycle and probably is controlled by environmental cues as well as endogenous signals. Sex steroids have been shown to regulate dopaminergic systems in several teleost species, affecting both DA synthesis and DA-D2 receptor expression. This demonstrates that sex steroid feedbacks target DA hypophysiotropic system, as well as the other components of the brain-pituitary gonadotrophic axis, GnRH and gonadotrophins. Recent studies have revealed that melatonin modulates the activity of DA systems in some teleosts, making the melatonin-DA pathway a prominent relay between environmental cues and control of reproduction. The recruitment of DA neurons for the neuroendocrine control of reproduction provides an additional brain pathway for the integration of various internal and environmental cues. The plasticity of the DA neuroendocrine role observed in teleosts may have contributed to their large diversity of reproductive cycles.
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Affiliation(s)
- S Dufour
- Muséum National d'Histoire Naturelle, UMR Biologie des Organismes et Ecosystèmes Aquatiques" MNHN-CNRS-IRD-UPMC, 7 rue Cuvier, CP 32, 75231 Paris Cedex 05, France.
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15
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van der Kraak G. Chapter 3 The GnRH System and the Neuroendocrine Regulation of Reproduction. FISH PHYSIOLOGY 2009. [DOI: 10.1016/s1546-5098(09)28003-4] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
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16
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Dufour S, Weltzien FA, Sebert ME, Le Belle N, Vidal B, Vernier P, Pasqualini C. Dopaminergic Inhibition of Reproduction in Teleost Fishes: Ecophysiological and Evolutionary Implications. Ann N Y Acad Sci 2006; 1040:9-21. [PMID: 15891002 DOI: 10.1196/annals.1327.002] [Citation(s) in RCA: 90] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
In many teleosts, dopamine (DA) exerts direct inhibitory control on gonadotropes, counteracting the stimulatory effect of gonadotropin-releasing hormone (GnRH) on gonadotropin release. This dual control by GnRH and DA has been demonstrated in various adult teleosts and has major implications for aquaculture. Because of its unique life cycle, the European eel has provided a powerful model for demonstrating the key role of DA in the control of puberty. Data from tetrapods suggest that the inhibitory role of DA on reproduction is not restricted to the teleosts. Thus, DA inhibitory control could represent an ancient evolutionary component in the neuroendocrine regulation of reproduction that may have been differentially maintained throughout vertebrate evolution. The intensity of DA inhibition, its main site of action, and its involvement in the control of puberty, seasonal reproduction, ovulation, spermiation, or even sex change may differ among classes of vertebrates, as well as within smaller phylogenetic units such as teleosts or mammals. An inhibitory role for DA has been reported also in some invertebrates, indicating that neuronal DA pathways may have been recruited in various groups of metazoa to participate in the control of reproduction. In addition to the incontestable GnRH neurons, the recruitment of DA neurons for the neuroendocrine control of reproduction provides an additional brain pathway for the integration of various species-specific, internal, and environmental cues. In teleosts, the plasticity of the DA neuroendocrine role may have contributed to their large diversity of biological cycles and to their successful adaptation to various environments.
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Affiliation(s)
- S Dufour
- USM 0401, UMR CNRS/MNHN/UPMC 5178, Biologie des Organismes Marins et Ecosystèmes, DMPA, Muséum National d'Histoire Naturelle, Paris, France.
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17
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Vidal B, Pasqualini C, Le Belle N, Holland MCH, Sbaihi M, Vernier P, Zohar Y, Dufour S. Dopamine Inhibits Luteinizing Hormone Synthesis and Release in the Juvenile European Eel: A Neuroendocrine Lock for the Onset of Puberty1. Biol Reprod 2004; 71:1491-500. [PMID: 15229141 DOI: 10.1095/biolreprod.104.030627] [Citation(s) in RCA: 91] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/01/2022] Open
Abstract
In various adult teleost fishes, LH ovulatory peak is under a dual neurohormonal control that is stimulatory by GnRH and inhibitory by dopamine (DA). We investigated whether DA could also be involved in the inhibitory control of LH at earlier steps of gametogenesis by studying the model of the European eel, Anguilla anguilla, which remains at a prepubertal stage until the oceanic reproductive migration. According to a protocol previously developed in the striped bass, eels received sustained treatments with GnRH agonist (GnRHa), DA-receptor antagonist (pimozide), and testosterone (T) either alone or in combination. Only the triple treatment with T, GnRHa, and pimozide could trigger dramatic increases in LH synthesis and release as well as in plasma vitellogenin levels and a stimulation of ovarian vitellogenesis. Thus, in the prepubertal eel, removal of DA inhibition is required for triggering GnRH-stimulated LH synthesis and release as well as ovarian development. To locate the anatomical support for DA inhibition, the distribution of tyrosine hydroxylase (TH) in the brain and pituitary was studied by immunocytochemistry. Numerous TH-immunoreactive cell bodies were observed in the preoptic anteroventral nucleus, with a dense tract of immunoreactive fibers reaching the pituitary proximal pars distalis, where the gonadotrophs are located. This pathway corresponds to that mediating the inhibition of LH and ovulation in adult teleosts. To our knowledge, this is the first demonstration of a pivotal role for DA in the control of LH and puberty in a juvenile teleost. These data support the view that DA inhibition on LH secretion is an ancient evolutionary component in the neuroendocrine regulation of reproduction that may have been partially maintained throughout vertebrate evolution.
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Affiliation(s)
- Bernadette Vidal
- USM 0401, UMR 5178 CNRS/MNHN/UPMC Biologie des Organismes Marins et Ecosystèmes, DMPA, Muséum National d'Histoire Naturelle, 7 rue Cuvier, 75231 Paris Cedex 05, France
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18
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Kumakura N, Okuzawa K, Gen K, Yamaguchi S, Lim BS, Kagawa H. Effects of gonadotropin-releasing hormone on pituitary-ovarian axis of one-year old pre-pubertal red seabream. Gen Comp Endocrinol 2004; 138:105-12. [PMID: 15302259 DOI: 10.1016/j.ygcen.2004.05.008] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/30/2003] [Revised: 05/11/2004] [Accepted: 05/18/2004] [Indexed: 10/26/2022]
Abstract
To identify the pubertal development of the brain-pituitary-gonad (BPG) axis in female red seabream (Pagrus major), we investigated the effects of gonadotropin-releasing hormone agonist (GnRHa) on seabream (sb) GnRH mRNA levels in the brain, gonadotropin subunit mRNA levels in the pituitary, and serum concentrations of luteinizing hormone (LH), testosterone (T) and estradiol-17beta (E2) in pre-pubertal fish. Sexually immature 12-month-old fish were implanted with a cholesterol pellet containing GnRHa and maintained for 10-20 days. In the brain, GnRHa had no effect on sbGnRH mRNA levels. In the pituitary, although no marked changes were observed in follicle-stimulating hormone (FSH) beta subunit mRNA levels, the expression of glycoprotein (GP) alpha, and LHbeta subunit genes in the pituitary was drastically up-regulated (approximately 4- and 5-fold, respectively) and serum LH levels were also increased (approximately 3-fold) by GnRHa implantation. However, ovaries of GnRHa treated fish contained only oocytes at the peri-nucleolus stage, and oocyte development such as vitellogenesis and oocyte maturation did not occur throughout the experimental period. In these fish, even though LH was released, only slight increases in serum concentrations of T and E2 were observed. These results indicate that the pituitary gonadotropin cells of pre-pubertal 12-month-old fish were already receptive to GnRH stimulus, and acquired the ability to synthesize and release of LH as in the case of adult fish. Deficient factors for the onset of puberty by GnRHa treatment will be discussed.
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Affiliation(s)
- Naoki Kumakura
- Department of Aquatic Biosciences, Tokyo University of Fisheries, Minato, Tokyo 108-8477, Japan
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19
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Noaksson E, Gustavsson B, Linderoth M, Zebühr Y, Broman D, Balk L. Gonad development and plasma steroid profiles by HRGC/HRMS during one reproductive cycle in reference and leachate-exposed female perch (Perca fluviatilis). Toxicol Appl Pharmacol 2004; 195:247-61. [PMID: 14998689 DOI: 10.1016/j.taap.2003.11.017] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2003] [Accepted: 11/20/2003] [Indexed: 10/26/2022]
Abstract
Endocrine processes were studied in reference female perch (Perca fluviatilis) from Lake Djursjön and in leachate-exposed females from Lake Molnbyggen during one reproductive cycle. A high-resolution gas chromatography/high-resolution mass spectrometry (HRGC/HRMS) technique enabled the analysis of circulating sex steroids [progesterone (P), 17alpha-hydroxyprogesterone (17alpha-OHP), androstenedione (A), testosterone (T), estrone (E1), and 17beta-estradiol (E2)], the maturation-inducing hormone (MIH) 17alpha,20beta-dihydroxy-4-pregnen-3-one (17alpha,20beta-P), and glucocorticoids [11-deoxycortisol (11-DC) and cortisol]. Body and organ measurements, ratio of sexually mature (SM) females, and frequencies of body lesions, were also recorded. High frequencies of body lesions and a low ratio of SM females were generally found in Molnbyggen. These females also had lower gonadosomatic index (GSI) and liver-somatic index (LSI) in the early stages of vitellogenesis, indicating either a delayed onset of oogenesis or an impaired vitellogenesis. Non-reproducing females from both lakes showed a similar LSI cycle as SM females. Increasing T and A levels in SM females from Djursjön coincided with the GSI peak at the time of spawning. These two androgens were on several occasions lower in SM females from Molnbyggen, possibly the result of a disrupted 17,20-lyase activity of the P450 17alpha enzyme because only minor effects were observed on circulating P and 17alpha-OHP levels. E2 and E1 levels increased during vitellogenesis in females from both lakes, with E1 levels more closely resembling the peaks of A and GSI. Peak levels of 17alpha,20beta-P at the time of spawning confirmed its function as the MIH in perch, while the simultaneous peak of 11-DC suggests that it also may be involved in final maturation of the oocytes.
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Affiliation(s)
- Erik Noaksson
- Laboratory for Aquatic Ecotoxicology, Institute of Applied Environmental Research, Stockholm University, SE-106 91 Stockholm, Sweden.
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20
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Noaksson E, Linderoth M, Bosveld ATC, Balk L. Altered steroid metabolism in several teleost species exposed to endocrine disrupting substances in refuse dump leachate. Gen Comp Endocrinol 2003; 134:273-84. [PMID: 14636634 DOI: 10.1016/s0016-6480(03)00267-3] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Endocrine disruption associated with reproductive failure has been reported previously in female perch (Perca fluviatilis) and roach (Rutilus rutilus) from Lake Molnbyggen in Sweden and in female brook trout (Salvelinus fontinalis) from Vadbäcken, a stream emptying into Molnbyggen. Both Molnbyggen and Vadbäcken have been contaminated by toxic leachate from a municipal refuse dump. In this study, female perch were caught in Molnbyggen and the reference lake, Lake Djursjön, to further investigate the endocrine mechanism behind the significant numbers of sexually immature (SIM) female perch in Molnbyggen. Blood plasma analysis of progesterone (P), 17alpha-hydroxyprogesterone (17alpha-OHP), testosterone (T), and 17beta-oestradiol (E2), as well as analysis of brain aromatase activity (P450arom), were carried out. The exceptional high numbers of SIM female perch in Molnbyggen was confirmed in February 1999. In July 1999, at an early stage of oogenesis, perch from Molnbyggen showed significantly decreased gonadosomatic index (GSI) and aromatase activity. The presence of aromatase inhibiting substances in lake sediments were therefore tested in vitro. The aromatase activity was dose-dependently inhibited by clotrimazole, reaching 50% inhibition at a concentration of 0.9 microM. Aromatase inhibiting substances were found both in Molnbyggen and reference sediment extracts, indicating that they were naturally occurring substances and not of anthrophogenic origin. The similar decrease in levels of circulating steroids (P, 17alpha-OHP, T, and E2), aromatase, and GSI therefore suggest that the low aromatase activity is due to down-regulation rather than inhibition. To further investigate the steroidogenesis prior to T, P, and 17alpha-OHP were analysed in perch caught in 1997 and 1998 in Lakes Molnbyggen, Kvarntjärn (downstream), Yxen (upstream), and Djursjön, in female roach caught in Molnbyggen and Djursjön in 1997, and in brook trout caught in Vadbäcken and the reference stream Björntjärnsbäcken in 1998. The absence of differences in P and 17alpha-OHP levels, combined with a significantly lower T level in female perch and roach from Molnbyggen in 1997, could be the result of either increased metabolism and excretion of T, or a disruption downstream of 17alpha-OHP formation. The unaffected P levels and significantly lower 17alpha-OHP levels, together with significantly decreased T and E2 levels, found in adult (>45g) female brook trout from Vadbäcken, further indicated that an altered steroidogenesis downstream of P is one possible mechanism underlying the low T levels and thus the high number of SIM female fish, since too low T levels might be insufficient to activate the brain-pituitary-gonadal axis.
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Affiliation(s)
- Erik Noaksson
- Laboratory for Aquatic Ecotoxicology, Institute of Applied Environmental Research, Stockholm University, S-106 91 Stockholm, Sweden.
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21
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Kumakura N, Okuzawa K, Gen K, Kagawa H. Effects of gonadotropin-releasing hormone agonist and dopamine antagonist on hypothalamus-pituitary-gonadal axis of pre-pubertal female red seabream (Pagrus major). Gen Comp Endocrinol 2003; 131:264-73. [PMID: 12714008 DOI: 10.1016/s0016-6480(03)00012-1] [Citation(s) in RCA: 56] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
The effects of GnRH agonist (GnRHa) on the hypothalamus-pituitary-gonadal axis were studied in female pre-pubertal red seabream. Sexually immature 16-month-old fish were implanted intramuscularly with cholesterol pellets containing GnRHa or GnRHa in combination with domperidone, putative dopamine antagonist, and reared for 10-20 days. In both GnRHa and GnRHa+domperidone implanted groups, vitellogenesis was observed on Day 10 and ovulation was observed on Day 20, while ovarian development was not observed in the control fish throughout the experimental period. The levels of GnRH receptor mRNA were significantly higher in both GnRHa implanted groups than in the control. The expressions of all three gonadotropin subunit genes were up-regulated and serum luteinizing hormone levels were increased by the GnRHa implantation. Serum testosterone and estradiol-17beta levels were also increased on Day 10 and maintained high levels on Day 20. On the other hand, seabream (sb) GnRH mRNA levels in the brain were relatively low and unchanged in all experiment groups. The present study first shows that GnRH alone can induce precocious puberty in red seabream. These results indicate that the system of pituitary-gonadal axis has already been developed in 16-month-old fish and the commencement of sbGnRH secretion may be an important physiological event for the onset of puberty in the red seabream.
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Affiliation(s)
- Naoki Kumakura
- Department of Aquatic Biosciences, Tokyo University of Fisheries, Minato, Tokyo 108-8477, Japan
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22
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Holland MCH, Hassin S, Zohar Y. The effects of long-term testosterone, gonadotropin-releasing hormone agonist and pimozide treatments on testicular development and luteinizing hormone levels in juvenile and early maturing striped bass, Morone saxatilis. Gen Comp Endocrinol 2002; 129:178-87. [PMID: 12460602 DOI: 10.1016/s0016-6480(02)00532-4] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
The present study was conducted to test the responsiveness of the juvenile male reproductive axis to hormonal stimulation and to compare it to that of early maturing males. Long-term treatments with various combinations of T, GnRHa and pimozide did not result in an increased incidence of early maturing males, but did stimulate spermatogenesis slightly in juvenile fish. In early maturing males, the treatments appeared to be inhibitory since they resulted in a reduction of the GSI and a lower incidence of spermiating males. In early maturing males, pituitary LH content was elevated by GnRHa treatments alone while in juvenile males a combination of T and GnRHa was needed to increase the levels of LH in the pituitary. Thus, T may play an important role during puberty by potentiating the effects of GnRH on LH synthesis. In both juvenile and early maturing males, plasma LH levels could be increased only by high doses of GnRHa (in combination with T). Therefore, LH synthesis and release probably require different levels of GnRH stimulation. A GnRH challenge (single injection of 50 microg GnRHa/kg) at the end of the experiment resulted in a dramatic elevation of plasma LH levels in almost all animals. This finding demonstrates that pituitaries from juvenile and early maturing males were responsive to GnRHa stimulation, even after long-term hormonal treatments. The addition of pimozide did not affect the T- and GnRHa-induced increase in pituitary LH content but inhibited the release of LH in response to a GnRHa challenge. In conclusion, high doses of GnRHa in combination with T can increase plasma LH levels in juvenile males but do not induce complete testicular maturation. Factors other than T, GnRHa or LH are probably involved in the induction and completion of spermatogenesis.
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Affiliation(s)
- M Claire H Holland
- Center of Marine Biotechnology, University of Maryland Biotechnology Institute, Suite 236, Columbus Center, 701 East Pratt Street, Baltimore 21202, USA
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Mateos J, Mañanos E, Carrillo M, Zanuy S. Regulation of follicle-stimulating hormone (FSH) and luteinizing hormone (LH) gene expression by gonadotropin-releasing hormone (GnRH) and sexual steroids in the Mediterranean Sea bass. Comp Biochem Physiol B Biochem Mol Biol 2002; 132:75-86. [PMID: 11997211 DOI: 10.1016/s1096-4959(01)00535-8] [Citation(s) in RCA: 89] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The secretion of gonadotropins, the key reproductive hormones in vertebrates, is controlled from the brain by the gonadotropin-releasing hormone (GnRH), but also by complex steroid feedback mechanisms. In this study, after the recent cloning of the three gonadotropin subunits of sea bass (Dicentrarchus labrax), we aimed at investigating the effects of GnRH and sexual steroids on pituitary gonadotropin mRNA levels, in this valuable aquaculture fish species. Implantation of sea bass, in the period of sexual resting, for 12 days with estradiol (E2), testosterone (T) or the non-aromatizable androgen dihydrotestosterone (DHT), almost suppressed basal expression of FSHbeta (four to 15-fold inhibition from control levels), while slightly increasing that of alpha (1.5-fold) and LHbeta (approx. twofold) subunits. Further injection with a GnRH analogue (15 microg/kg BW; [D-Ala6, Pro9-Net]-mGnRH), had no effect on FSHbeta mRNA levels, but stimulated (twofold) pituitary alpha and LHbeta mRNA levels in sham- and T-implanted fish, and slightly in E2- and DHT-implanted fish (approx. 1.5-fold). The GnRHa injection, as expected, elevated plasma LH levels with a parallel decrease on LH pituitary content, with no differences between implanted fish. In conclusion, high circulating steroid levels seems to exert different action on gonadotropin secretion, inhibiting FSH while stimulating LH synthesis. In these experimental conditions, the GnRHa stimulate LH synthesis and release, but have no effect on FSH synthesis.
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Affiliation(s)
- Jorge Mateos
- Instituto de Acuicultura de Torre la Sal (C.S.I.C.), Ribera de Cabanes s/n, 12595-Torre la Sal, Castellón, Spain
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Tiwary BK, Kirubagaran R, Ray AK. Testosterone triggers the brain-pituitary-gonad axis of juvenile female catfish (Heteropneustes fossilis Bloch) for precocious ovarian maturation. Gen Comp Endocrinol 2002; 126:23-9. [PMID: 11944963 DOI: 10.1006/gcen.2001.7751] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The brain-pituitary-gonad axis of precociously matured females (PMFs) of Indian catfish (Heteropneustes fossilis), produced by testosterone treatment during juvenile stages, was analyzed by studies on immunoreactive gonadotropin-releasing hormone (ir-GnRH) secreting cells of the preoptic area of brain, plasma levels of gonadotropin (GtH-II), testosterone (T), and estradiol-17 beta (E(2)). GnRH cells of PMFs were large and strongly immunoreactive in comparison to control females. PMFs showed higher plasma levels of GtH-II, T, and E(2) than did control females. The ovaries of PMFs contained ripe ova, whereas control females had ova at maturing stages. This study suggests testosterone-mediated activation of the brain-pituitary-ovarian axis for precocious maturation in juvenile catfish.
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Affiliation(s)
- Basant K Tiwary
- Department of Animal Physiology, Bose Institute, P-1/12, CIT Scheme VII M, Calcutta-700 054, India
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Hassin S, Holland MC, Zohar Y. Early maturity in the male striped bass, Morone saxatilis: follicle-stimulating hormone and luteinizing hormone gene expression and their regulation by gonadotropin-releasing hormone analogue and testosterone. Biol Reprod 2000; 63:1691-7. [PMID: 11090437 DOI: 10.1095/biolreprod63.6.1691] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/01/2022] Open
Abstract
Striped bass are seasonal breeding fish, spawning once a year during the spring. All 3-yr-old males are sexually mature; however, 60-64% of the fish mature earlier as 1- or 2-yr-old animals. The endocrine basis underlying early maturity in 2-yr-old males was studied at the molecular level by monitoring changes in pituitary beta FSH and beta LH mRNA levels by ribonuclease protection assay, and correlating these changes to stages of testicular development. In maturing males, the mRNA levels of beta FSH were elevated during early spermatogenesis, whereas beta LH mRNA levels peaked during spermiation. The appearance of spermatozoa in the testis was associated with a decrease in beta FSH mRNA and a rise in beta LH mRNA abundance. Immature males had lower levels of beta LH mRNA than maturing males, but there were no differences in beta FSH mRNA levels between immature and maturing males. The regulation of gonadotropin gene expression in 2-yr-old males was studied by the chronic administration of GnRH analogue (GnRHa) and testosterone (T), with or without pimozide (P) supplementation. In immature males, the combination of T and GnRHa stimulated a three- to fivefold increase in beta FSH and beta LH mRNA levels, but the same treatment had no effect on gonadotropin gene expression in maturing males. In addition, the coadministration of P to immature males suppressed the stimulatory effect of GnRHa and T on beta FSH and beta LH mRNA levels, suggesting that dopamine may have a novel role in regulating gonadotropin gene expression.
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Affiliation(s)
- S Hassin
- Center of Marine Biotechnology, University of Maryland Biotechnology Institute, Baltimore, Maryland 21202, USA
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Holland MC, Hassin S, Zohar Y. Gonadal development and plasma steroid levels during pubertal development in captive-reared striped bass, Morone saxatilis. THE JOURNAL OF EXPERIMENTAL ZOOLOGY 2000; 286:49-63. [PMID: 10607368 DOI: 10.1002/(sici)1097-010x(20000101)286:1<49::aid-jez5>3.0.co;2-3] [Citation(s) in RCA: 45] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Puberty is the period during which full sexual development occurs and the capacity to reproduce is acquired. Despite its importance, our understanding of the endocrine regulation of puberty in lower vertebrates is still limited. The objective of the present study was to describe the changes in gonadal development and plasma steroid levels in a relatively late maturing species, the striped bass, during the first four years of life. In about 65% of the females, puberty was initiated during the third year. Although gonadosomatic index (GSI) and oocyte diameter increased during this year, this first cycle was characterized by a heterogeneous population of developing oocytes, a relatively low mean maximum oocyte diameter, and an absence of yolk granules in the oocytes. Plasma 17beta-estradiol (E(2)) levels were low in all three-year-old fish, suggesting that an insufficient stimulation of vitellogenin production by E(2) may underlie the lack of vitellogenin incorporation into developing oocytes. All monitored parameters increased during the fourth year, but were still below the values attained by older females. In about 60% of the males, puberty was initiated during the first year and all males were mature by the third year. During the first two years, several immature males initiated spermatogenesis without reaching full maturity. In mature males, mean GSI, plasma testosterone, and 11-ketotestosterone levels increased simultaneously, reaching higher values each subsequent year. Our results indicate that, similar to the situation in mammals, more than one reproductive cycle is required in striped bass before complete adulthood is reached.
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Affiliation(s)
- M C Holland
- Center of Marine Biotechnology, University of Maryland Biotechnology Institute, Baltimore, Maryland 21202, USA
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Khan IA, Hawkins MB, Thomas P. Gonadal stage-dependent effects of gonadal steroids on gonadotropin II secretion in the Atlantic croaker (Micropogonias undulatus). Biol Reprod 1999; 61:834-41. [PMID: 10456865 DOI: 10.1095/biolreprod61.3.834] [Citation(s) in RCA: 41] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/01/2022] Open
Abstract
Involvement of gonadal steroids in the control of gonadotropin II (GTH II) (homologous to LH) secretion was investigated in the Atlantic croaker (Micropogonias undulatus) using gonadectomy (Gx) and steroid replacement paradigms. Gonadectomy in males and females during the late gonadal recrudescence phase elicited significant increases in the gonadotropin response to stimulation by an LHRH analog (LHRHa), without altering basal GTH II secretion. Slow-release silicone elastomer implants of testosterone or estradiol significantly inhibited LHRHa-induced GTH II secretion in gonad-intact and Gx males, and in Gx females, whereas 5alpha-dihydrotestosterone, a nonaromatizable androgen, was ineffective. Pretreatment of fish with an aromatase inhibitor, 1,4, 6-androstatrien-3,17-dione, 2 days before the administration of testosterone implants, completely blocked the negative effect of testosterone on LHRHa-induced GTH II secretion in males, but only partially restored it in females. This suggests that the negative feedback of testosterone in males is primarily mediated by its conversion to estradiol at the level of the hypothalamus and/or pituitary gland, while in females the androgen may also exert a direct inhibitory effect on GTH II secretion, probably mediated via an androgen receptor. In addition, estradiol and testosterone exerted positive effects on basal and LHRHa-induced GTH II secretion during the early-recrudescence phase of the gonadal cycle. The steroids switched to a negative effect on LHRHa-induced GTH II secretion once the fish had fully developed gonads, possibly as a mechanism that prevents a precocious surge in GTH II secretion and final gamete maturation until gametogenesis is complete and the environmental conditions are appropriate for spawning.
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Affiliation(s)
- I A Khan
- The University of Texas at Austin, Marine Science Institute, Port Aransas, Texas 78373, USA.
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