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Mizrahi N, Hollander-Cohen L, Atre I, Shulman M, Campo A, Levavi-Sivan B. Characterization of the somatostatin system in tilapia: implications for growth and reproduction. Front Endocrinol (Lausanne) 2024; 15:1302672. [PMID: 38974572 PMCID: PMC11224465 DOI: 10.3389/fendo.2024.1302672] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/14/2023] [Accepted: 05/30/2024] [Indexed: 07/09/2024] Open
Abstract
Somatostatin (SST) plays diverse physiological roles in vertebrates, particularly in regulating growth hormone secretion from the pituitary. While the function of SST as a neuromodulator has been studied extensively, its role in fish and mammalian reproduction remains poorly understood. To address this gap, we investigated the involvement of the somatostatin system in the regulation of growth and reproductive hormones in tilapia. RNA sequencing of mature tilapia brain tissue revealed the presence of three SST peptides: SST6, SST3, and low levels of SST1. Four different isoforms of the somatostatin receptor (SSTR) subfamily were also identified in the tilapia genome. Phylogenetic and synteny analysis identified tiSSTR2-like as the root of the tree, forming two mega clades, with SSTR1 and SSTR4 in one and SSTR2a, SSTR3a, and SSTR5b in the other. Interestingly, the tiSSTR-5 isoforms 5x1, 5x2, and 5x3 were encoded in the sstr3b gene and were an artifact of misperception in the nomenclature in the database. RNA-seq of separated pituitary cell populations showed that SSTRs were expressed in gonadotrophs, with sstr3a enriched in luteinizing hormone (LH) cells and sstr3b significantly enriched in follicle-stimulating hormone (FSH) cells. Notably, cyclosomatostatin, an SSTR antagonist, induced cAMP activity in all SSTRs, with SSTR3a displaying the highest response, whereas octreotide, an SSTR agonist, showed a binding profile like that observed in human receptors. Binding site analysis of tiSSTRs from tilapia pituitary cells revealed the presence of canonical binding sites characteristic of peptide-binding class A G-protein-coupled receptors. Based on these findings, we explored the effect of somatostatin on gonadotropin release from the pituitary in vivo. Whereas cyclosomatostatin increased LH and FSH plasma levels at 2 h post-injection, octreotide decreased FSH levels after 2 h, but the LH levels remained unaffected. Overall, our findings provide important insights into the somatostatin system and its mechanisms of action, indicating a potential role in regulating growth and reproductive hormones. Further studies of the complex interplay between SST, its receptors, and reproductive hormones may advance reproductive control and management in cultured populations.
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Affiliation(s)
- Naama Mizrahi
- Department of Animal Sciences, The Robert H. Smith Faculty of Agriculture, Food, and Environment, Hebrew University of Jerusalem, Rehovot, Israel
| | - Lian Hollander-Cohen
- Department of Animal Sciences, The Robert H. Smith Faculty of Agriculture, Food, and Environment, Hebrew University of Jerusalem, Rehovot, Israel
| | - Ishwar Atre
- Department of Animal Sciences, The Robert H. Smith Faculty of Agriculture, Food, and Environment, Hebrew University of Jerusalem, Rehovot, Israel
| | - Miriam Shulman
- Department of Animal Sciences, The Robert H. Smith Faculty of Agriculture, Food, and Environment, Hebrew University of Jerusalem, Rehovot, Israel
| | - Aurora Campo
- Department of Poultry and Aquaculture, Institute of Animal Sciences, Agricultural Research Organization, Rishon LeZion, Israel
| | - Berta Levavi-Sivan
- Department of Animal Sciences, The Robert H. Smith Faculty of Agriculture, Food, and Environment, Hebrew University of Jerusalem, Rehovot, Israel
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Atre I, Mizrahi N, Levavi-Sivan B. Characteristics of Neurokinin-3 Receptor and Its Binding Sites by Mutational Analysis. BIOLOGY 2021; 10:biology10100968. [PMID: 34681067 PMCID: PMC8533089 DOI: 10.3390/biology10100968] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/26/2021] [Revised: 09/13/2021] [Accepted: 09/23/2021] [Indexed: 11/16/2022]
Abstract
NKB (Neurokinin B) is already known to play a crucial role in fish reproduction, but little is known about the structure and function of NKB receptors. Based on an in silico model of the tilapia NKB receptor Tachykinin 3 receptor a (tiTac3Ra) found in the current study, we determined the key residues involved in binding to tilapia NKB and its functional homologue NKF (Neurokinin F). Despite studies in humans suggesting the crucial role of F2516.44 and M2897.43 in NKB binding, no direct peptide interaction was observed in tilapia homologs. In-silico, Ala mutations on residues F2516.44 and M2897.43 did not influence binding affinity, but significantly affected the stability of tiTac3Ra. Moreover, in vitro studies indicated them to be critical to tiNKB/tiNKF-induced receptor activity. The binding of NKB antagonists to tiTac3Ra both in-vitro and in vivo inhibits FSH (follicle stimulating hormone) and LH (luteinizing hormone) release and sperm production in mature tilapia males. Non-peptide NKB antagonist SB-222200 had a strong inhibitory effect on the Tac3Ra activation. SB-222200 also decreased LH plasma levels; two hours post intraperitoneal injection, changed sperm volume and the ratios of the different stages along the spermatogenesis in tilapia testes.
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Chen S, Guo X, He X, Di R, Zhang X, Zhang J, Wang X, Chu M. Transcriptome Analysis Reveals Differentially Expressed Genes and Long Non-coding RNAs Associated With Fecundity in Sheep Hypothalamus With Different FecB Genotypes. Front Cell Dev Biol 2021; 9:633747. [PMID: 34095109 PMCID: PMC8172604 DOI: 10.3389/fcell.2021.633747] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2020] [Accepted: 03/25/2021] [Indexed: 12/30/2022] Open
Abstract
Small-tailed Han sheep, with different FecB genotypes, manifest distinct ovulation rates and fecundities, which are due to differences in reproductive hormones secreted by the hypothalamic-pituitary-ovarian axis. Nevertheless, the function of the hypothalamus against a FecB mutant background on increasing ovulation rate is rarely reported. Therefore, we determined the expression profiles of hypothalamus tissue collected from six wild-type (WW) and six FecB mutant homozygous (BB) ewes at the follicular and luteal phases by whole-transcriptome sequencing. We identified 53 differentially expressed mRNAs (DEGs) and 40 differentially expressed long non-coding RNAs (DELs) between the two estrus states. Functional annotation analysis revealed that one of the DEGs, PRL, was particularly enriched in the hypothalamic function, hormone-related, and reproductive pathways. The lncRNA-target gene interaction networks and KEGG analysis in combination suggest that the lncRNAs LINC-676 and WNT3-AS cis-acting on DRD2 and WNT9B in different phases may induce gonadotropin-releasing hormone (GnRH) secretion. Furthermore, there were differences of regulatory elements and WNT gene family members involved in the follicular-luteal transition in the reproductive process between wild-type (WNT7A) and FecB mutant sheep (WNT9B). We combined the DEG and DEL data sets screened from different estrus states and genotypes. The overlap of these two sets was identified to select the mRNAs and lncRNAs that have major effects on ovulation. Among the overlapping molecules, seven DEGs and four DELs were involved in the follicular-luteal transition regulated by FecB mutation. Functional annotation analysis showed that two DEGs (FKBP5 and KITLG) were enriched in melanogenesis, oxytocin, and GnRH secretion. LINC-219386 and IGF2-AS were highly expressed in the BB ewes compared with WW ewes, modulating their target genes (DMXL2 and IGF2) to produce more GnRH during follicular development, which explains why mutated ewes produced more mature follicles. These results from expression profiling of the hypothalamus with the FecB mutation at different estrus states provide new insights into how the hypothalamus regulates ovulation under the effect of the FecB mutation.
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Affiliation(s)
- Si Chen
- Key Laboratory of Animal Genetics, Breeding and Reproduction, Ministry of Agriculture and Rural Affairs, Institute of Animal Science, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Xiaofei Guo
- Key Laboratory of Animal Genetics, Breeding and Reproduction, Ministry of Agriculture and Rural Affairs, Institute of Animal Science, Chinese Academy of Agricultural Sciences, Beijing, China.,Tianjin Institute of Animal Sciences, Tianjin, China
| | - Xiaoyun He
- Key Laboratory of Animal Genetics, Breeding and Reproduction, Ministry of Agriculture and Rural Affairs, Institute of Animal Science, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Ran Di
- Key Laboratory of Animal Genetics, Breeding and Reproduction, Ministry of Agriculture and Rural Affairs, Institute of Animal Science, Chinese Academy of Agricultural Sciences, Beijing, China
| | | | - Jinlong Zhang
- Tianjin Institute of Animal Sciences, Tianjin, China
| | - Xiangyu Wang
- Key Laboratory of Animal Genetics, Breeding and Reproduction, Ministry of Agriculture and Rural Affairs, Institute of Animal Science, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Mingxing Chu
- Key Laboratory of Animal Genetics, Breeding and Reproduction, Ministry of Agriculture and Rural Affairs, Institute of Animal Science, Chinese Academy of Agricultural Sciences, Beijing, China
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Tenugu S, Pranoty A, Mamta SK, Senthilkumaran B. Development and organisation of gonadal steroidogenesis in bony fishes - A review. AQUACULTURE AND FISHERIES 2021. [DOI: 10.1016/j.aaf.2020.09.004] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
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Badruzzaman M, Shahjahan M, Roy PK, Islam MT. Rotenone alters behavior and reproductive functions of freshwater catfish, Mystus cavasius, through deficits of dopaminergic neurons in the brain. CHEMOSPHERE 2021; 263:128355. [PMID: 33297277 DOI: 10.1016/j.chemosphere.2020.128355] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/21/2020] [Revised: 08/31/2020] [Accepted: 09/13/2020] [Indexed: 06/12/2023]
Abstract
Rotenone, commonly used as a pesticide in agriculture and as a piscicide in aquaculture, is a toxic compound that causes dopaminergic neuronal cell loss in the substantia nigra pars compacta of the brain. At the neuroendocrine level, dopamine (DA) drives behavioral (locomotion, emotion, feeding, and social interactions, etc.) and reproductive functions of fish. In the current investigation, we examined effects of rotenone toxicity on neurobehavioral and reproductive functions in whole brain and in selected brain regions in an Indian freshwater catfish, locally known as gulsha (Mystus cavasius). After fish were exposed to water containing rotenone at 0, 2.5, 25, and 250 μg/L for 2 days, significant reductions of DA, 3,4-dihydroxyphenylacetic acid (DOPAC; a DA metabolite), and their ratio (DOPAC/DA) were observed in whole brain at 250 μg/L ambient concentrations of rotenone. When fish were treated with rotenone at 250 μg/L concentration for 2 days, there was a significant reduction of DA, DOPAC and DOPAC/DA in diencephalon, DA and DOPAC in pituitary, and only DA in the telencephalon, compared with control fish. In parallel, numbers of tyrosine hydroxylase-positive (TH+) neurons declined significantly in the diencephalon and pituitary after rotenone treatment. Slowed, spontaneous movement and reduced feeding behavior were observed in rotenone-treated fish. Rotenone treatment resulted in a significantly higher gonadosomatic index with many mature vitellogenic oocytes in ovaries and lowered dopaminergic activity in these fish. These results indicate that rotenone influences neurobehavioral and reproductive functions through dopaminergic neuronal cell loss in gulsha brain.
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Affiliation(s)
- Muhammad Badruzzaman
- Department of Biochemistry and Molecular Biology, Bangabandhu Sheikh Mujibur Rahman Agricultural University, Salna, Gazipur, 1706, Bangladesh.
| | - Md Shahjahan
- Laboratory of Fish Ecophysiology, Department of Fisheries Management, Bangladesh Agricultural University, Mymensingh, 2202, Bangladesh
| | - Prodip Kumar Roy
- Chemistry and Chemical Bioengineering Unit, Okinawa Institute of Science and Technology Graduate University, Okinawa, 904-0495, Japan
| | - Md Taimur Islam
- Department of Pathobiology, Bangabandhu Sheikh Mujibur Rahman Agricultural University, Salna, Gazipur, 1706, Bangladesh
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Fontaine R, Ciani E, Haug TM, Hodne K, Ager-Wick E, Baker DM, Weltzien FA. Gonadotrope plasticity at cellular, population and structural levels: A comparison between fishes and mammals. Gen Comp Endocrinol 2020; 287:113344. [PMID: 31794734 DOI: 10.1016/j.ygcen.2019.113344] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/30/2019] [Revised: 10/27/2019] [Accepted: 11/26/2019] [Indexed: 12/22/2022]
Abstract
Often referred to as "the master gland", the pituitary is a key organ controlling growth, maturation, and homeostasis in vertebrates. The anterior pituitary, which contains several hormone-producing cell types, is highly plastic and thereby able to adjust the production of the hormones governing these key physiological processes according to the changing needs over the life of the animal. Hypothalamic neuroendocrine control and feedback from peripheral tissues modulate pituitary cell activity, adjusting levels of hormone production and release according to different functional or environmental requirements. However, in some physiological processes (e.g. growth, puberty, or metamorphosis), changes in cell activity may be not sufficient to meet the needs and a general reorganization of cell composition and pituitary structure may occur. Focusing on gonadotropes, this review examines plasticity at the cellular level, which allows precise and rapid control of hormone production and secretion, as well as plasticity at the population and structural levels, which allows more substantial changes in hormone production. Further, we compare current knowledge of the anterior pituitary plasticity in fishes and mammals in order to assess what has been conserved or not throughout evolution, and highlight important remaining questions.
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Affiliation(s)
- Romain Fontaine
- Department of Basic Sciences and Aquatic Medicine, Faculty of Veterinary Medicine, Norwegian University of Life Sciences, 0454 Oslo, Norway
| | - Elia Ciani
- Department of Pharmacy, Faculty of Mathematics and Natural Sciences, University of Oslo, 0316 Oslo, Norway
| | - Trude Marie Haug
- Department of Oral Biology, Faculty of Dentistry, University of Oslo, 0372 Oslo, Norway
| | - Kjetil Hodne
- Department of Basic Sciences and Aquatic Medicine, Faculty of Veterinary Medicine, Norwegian University of Life Sciences, 0454 Oslo, Norway
| | - Eirill Ager-Wick
- Department of Basic Sciences and Aquatic Medicine, Faculty of Veterinary Medicine, Norwegian University of Life Sciences, 0454 Oslo, Norway
| | - Dianne M Baker
- Department of Biological Sciences, University of Mary Washington, VA22401 Fredericksburg, VA, USA
| | - Finn-Arne Weltzien
- Department of Basic Sciences and Aquatic Medicine, Faculty of Veterinary Medicine, Norwegian University of Life Sciences, 0454 Oslo, Norway.
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Cejko BI, Krejszeff S, Judycka S, Targońska K, Kucharczyk D. Effect of different treatment agents and post-treatment latency times on spermiation stimulation of northern pike (Esox lucius) under controlled conditions. Theriogenology 2020; 142:260-267. [PMID: 31711700 DOI: 10.1016/j.theriogenology.2019.10.035] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2019] [Revised: 10/29/2019] [Accepted: 10/30/2019] [Indexed: 10/25/2022]
Abstract
The effect of different treatment agents, namely, carp pituitary homogenate (CPH), Ovaprim ([D-Arg6, Pro9NEt]-sGnRH + domperidone) and a dopamine-receptor antagonist (metoclopramide), on the stimulation of northern pike (Esox lucius) spermiation was tested under controlled conditions. To carry out the experiment, males (n = 84) were divided into four groups: control (n = 21); CPH (n = 21); Ovaprim (n = 21); metoclopramide (n = 21). The control group was given 0.9% NaCl but no hormonal treatment. After 24 h, sperm was collected from seven males belonging to control (n = 7), CPH (n = 7), Ovaprim (n = 7) and metoclopramide (n = 7). This procedure was repeated after 48 and 72 h post-treatment. At each time, sperm was collected from seven males from each group only once. After collection, the quantity and quality of sperm were determined. It was confirmed that the treatment agent and latency time (the time between treatment and sperm collection) are two factors affecting the quantity and quality of northern pike sperm collected under controlled conditions. The highest total sperm volume and total sperm production (TSP) were noted in the CPH group compared to the Ovaprim, metoclopramide and control groups. In contrast, the time of sperm collection affected the sperm concentration (SC), TSP and sperm pH. With increasing time, SC and TSP decreased, which indicated the occurrence of sperm hydration being part of the final sperm maturation process. Sperm maturation is in turn a consequence of increases in sperm pH and seminal plasma osmotic pressure between 48 and 72 h post-treatment. Sperm motility and sperm kinetic parameters were affected by treatment agent and the time of sperm collection. This indicates that the sperm's ability to move that is achieved in the optimal environment (in spermatic ducts) is dependent on both factors which determine sperm maturation in northern pike under controlled condition.
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Affiliation(s)
- Beata Irena Cejko
- Department of Gamete and Embryo Biology, Institute of Animal Reproduction and Food Research, Polish Academy of Sciences, Olsztyn, Poland.
| | - Sławomir Krejszeff
- Department of Aquaculture, Stanisław Sakowicz Inland Fisheries Institute, Olsztyn, Poland; Department of Lake and River Fisheries, Faculty of Environmental Sciences, University of Warmia and Mazury, Olsztyn, Poland
| | - Sylwia Judycka
- Department of Gamete and Embryo Biology, Institute of Animal Reproduction and Food Research, Polish Academy of Sciences, Olsztyn, Poland
| | - Katarzyna Targońska
- Department of Lake and River Fisheries, Faculty of Environmental Sciences, University of Warmia and Mazury, Olsztyn, Poland
| | - Dariusz Kucharczyk
- Department of Lake and River Fisheries, Faculty of Environmental Sciences, University of Warmia and Mazury, Olsztyn, Poland
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Khan EA, Bertotto LB, Dale K, Lille-Langøy R, Yadetie F, Karlsen OA, Goksøyr A, Schlenk D, Arukwe A. Modulation of Neuro-Dopamine Homeostasis in Juvenile Female Atlantic Cod ( Gadus morhua) Exposed to Polycyclic Aromatic Hydrocarbons and Perfluoroalkyl Substances. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2019; 53:7036-7044. [PMID: 31090407 DOI: 10.1021/acs.est.9b00637] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
The dopaminergic effect of PAH and PFAS mixtures, prepared according to environmentally relevant concentrations, has been studied in juvenile female Atlantic cod ( Gadus morhua). Benzo[a]pyrene, dibenzothiophene, fluorene, naphthalene, phenanthrene, and pyrene were used to prepare a PAH mixture, while PFNA, PFOA, PFOS, and PFTrA were used to prepare a PFAS mixture. Cod were injected intraperitoneally twice, with either a low (1×) or high (20×) dose of each compound mixture or their combinations. After 2 weeks of exposure, levels of plasma 17β-estradiol (E2) were significantly elevated in high PAH/high PFAS treated group. Brain dopamine/metabolite ratios (DOPAC/dopamine and HVA+DOPAC/dopamine) changed with E2 plasma levels, except for high PAH/low PFAS and low PAH/high PFAS treated groups. On the transcript levels, th mRNA inversely correlated with dopamine/metabolite ratios and gnrh2 mRNA levels. Respective decreases and increases of drd1 and drd2a after exposure to the high PAH dose were observed. Specifically, high PFAS exposure decreased both drds, leading to high plasma E2 concentrations. Other studied end points suggest that these compounds, at different doses and combinations, have different toxicity threshold and modes of action. These effects indicate potential alterations in the feedback signaling processes within the dopaminergic pathway by these contaminant mixtures.
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Affiliation(s)
- Essa A Khan
- Department of Biology , Norwegian University of Science and Technology (NTNU) , Høgskoleringen 5 , N-7491 Trondheim , Norway
| | - Luisa B Bertotto
- Department of Environmental Sciences , University of California-Riverside , California 92521 , United States
| | - Karina Dale
- Department of Biological Sciences , University of Bergen , N-5020 Bergen , Norway
| | - Roger Lille-Langøy
- Department of Biological Sciences , University of Bergen , N-5020 Bergen , Norway
| | - Fekadu Yadetie
- Department of Biological Sciences , University of Bergen , N-5020 Bergen , Norway
| | - Odd André Karlsen
- Department of Biological Sciences , University of Bergen , N-5020 Bergen , Norway
| | - Anders Goksøyr
- Department of Biological Sciences , University of Bergen , N-5020 Bergen , Norway
| | - Daniel Schlenk
- Department of Environmental Sciences , University of California-Riverside , California 92521 , United States
| | - Augustine Arukwe
- Department of Biology , Norwegian University of Science and Technology (NTNU) , Høgskoleringen 5 , N-7491 Trondheim , Norway
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Giroux M, Gan J, Schlenk D. The effects of bifenthrin and temperature on the endocrinology of juvenile Chinook salmon. ENVIRONMENTAL TOXICOLOGY AND CHEMISTRY 2019; 38:852-861. [PMID: 30681194 DOI: 10.1002/etc.4372] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/30/2018] [Revised: 11/20/2018] [Accepted: 01/19/2019] [Indexed: 06/09/2023]
Abstract
The San Francisco Bay delta (USA) is experiencing seasonally warmer waters attributable to climate change and receives rainstorm runoff containing pyrethroid pesticides. Chinook salmon (Oncorhynchus tshawytscha) inhabit the affected waterways from hatch through smoltification, and thus juvenile fish may experience both pyrethroid and warmer water exposures. The effects of higher temperatures and pesticide exposure on presmolt Chinook are unknown. To improve understanding of the potential interaction between temperature and pesticide exposure on salmonid development, juvenile alevin and fry were reared in 11, 16.4, and 19 °C freshwater for 11 d and 2 wk, respectively, and exposed to nominal concentrations of 0, 0.15, and 1.5 µg/L bifenthrin for the final 96 h of rearing. Estradiol-17β (E2), testosterone, triiodothyronine, and thyroxine levels were measured in whole-body homogenates using hormone-specific enzyme-linked immunosorbent assays. Brain gonadotropin-releasing hormone receptor (GnRH2), dopamine receptor 2A, and growth hormone 1 (GH1) mRNA levels were measured using quantitative PCR. Results showed significantly decreased survival and condition factors observed with increasing temperature in alevin. Alevin thyroid hormones increased significantly with temperature, but fry thyroid hormones trended toward a decrease at lower temperatures with increasing bifenthrin exposure. There were significant reductions in fry testosterone and E2 at 11 °C with increasing bifenthrin treatments and significant changes in GnRH2 and GH1 gene expression in both alevin and fry, indicating potential disruption of hormonal and signaling pathways. Environ Toxicol Chem 2019;38:852-861. © 2019 SETAC.
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Affiliation(s)
- Marissa Giroux
- Environmental Toxicology Graduate Program, University of California Riverside, Riverside, California, USA
| | - Jay Gan
- Department of Environmental Sciences, University of California Riverside, Riverside, California, USA
| | - Daniel Schlenk
- Department of Environmental Sciences, University of California Riverside, Riverside, California, USA
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Mizrahi N, Gilon C, Atre I, Ogawa S, Parhar IS, Levavi-Sivan B. Deciphering Direct and Indirect Effects of Neurokinin B and GnRH in the Brain-Pituitary Axis of Tilapia. Front Endocrinol (Lausanne) 2019; 10:469. [PMID: 31354632 PMCID: PMC6639853 DOI: 10.3389/fendo.2019.00469] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/02/2019] [Accepted: 06/28/2019] [Indexed: 02/03/2023] Open
Abstract
Neurokinin B (NKB) and its cognate receptor (NK3R) are emerging as important components of the neuroendocrine regulation of reproduction. Unlike mammalian tac3, which encodes only one mature peptide (namely NKB), two mature peptides are predicted for each tac3 gene in fish and frogs. Therefore, it was designated as Neurokinin F (NKF). Hormone analogs with high and long-lasting biological activity are important tools for physiological and biological research; however, the availability of piscine-specific analogs is very limited. Therefore, we have developed specific NKB and NKF analogs based on the structure of the mammalian NKB analog-senktide. These analogs, specifically designed for longer half-lives by methylation of proteolysis sites, exhibited activity equal to those of the native NKB and NKF in short-term signal-transduction assays of tilapia NKB receptors. However, the analogs were found to be able to significantly increase the release of luteinizing hormone (LH), follicle stimulating hormone (FSH) and growth hormone (GH) in tilapia, as fast as 1 h after intraperitoneal (IP) injection. The impact of the analogs on LH and FSH secretion lasted longer compared to the effect of native peptides and salmon GnRH analog (sGnRHa). In addition, we harvested pituitaries 24 h post injection and measured LH, FSH and GH mRNA synthesis. Both analogs elevated mRNA levels of LH and GH, but only NKB analog increased FSH mRNA levels in the pituitary and all GnRH forms in the brain. NKB receptors were co-localized with all three types the GnRH neurons in tilapia brain in situ. We previously showed a direct effect of NKB at the pituitary level, and these new results suggest that the stronger impact of the NKB analog on GTH release is also due to an indirect effect through the activation of GnRH neurons. These results suggest that novel synthetic NKB analogs may serve as a tool for both research and agricultural purposes. Finally, the biological activity and regulatory role of NKB in tilapia brain and pituitary suggest that the NKB/NKBR system in fish is an important reproductive regulator in a similar way to the kisspeptin system in mammals.
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Affiliation(s)
- Naama Mizrahi
- Faculty of Agriculture, Food and Environment, The Hebrew University, Rehovot, Israel
| | - Chaim Gilon
- Institute of Chemistry, The Hebrew University of Jerusalem, Jerusalem, Israel
| | - Ishwar Atre
- Faculty of Agriculture, Food and Environment, The Hebrew University, Rehovot, Israel
| | - Satoshi Ogawa
- Jeffrey Cheah School of Medicine and Health Sciences, Brain Research Institute, Monash University Malaysia, Bandar Sunway, Malaysia
| | - Ishwar S. Parhar
- Jeffrey Cheah School of Medicine and Health Sciences, Brain Research Institute, Monash University Malaysia, Bandar Sunway, Malaysia
| | - Berta Levavi-Sivan
- Faculty of Agriculture, Food and Environment, The Hebrew University, Rehovot, Israel
- *Correspondence: Berta Levavi-Sivan
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Burcea A, Popa GO, Florescu Gune IE, Gharbia S, Gaina G, Dudu A, Maereanu M, Hermenean A, Georgescu SE, Costache M. Gene expression involved in the sexual development of Best Beluga hybrid sturgeons. JOURNAL OF FISH BIOLOGY 2018; 93:1021-1026. [PMID: 30264488 DOI: 10.1111/jfb.13815] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/12/2018] [Accepted: 09/25/2018] [Indexed: 06/08/2023]
Abstract
The scope of this study is to investigate the expression of dmrt1, foxl2, ar, star and sox9 genes in the context of the gonad development stage of 21 month-old Best Beluga individuals. No significant difference was observed between males and females but the cyp17a1 gene showed higher expression in male than in female gonads. The results suggest that during sampling the females were in perinucleolar stage and the males in early spermatogenesis stage which led to specific patterns of expression for the investigated genes.
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Affiliation(s)
- Alexandru Burcea
- Department of Biochemistry and Molecular Biology, Faculty of Biology, University of Bucharest, Bucharest, Romania
| | - Gina-Oana Popa
- Department of Biochemistry and Molecular Biology, Faculty of Biology, University of Bucharest, Bucharest, Romania
| | - Iulia E Florescu Gune
- Department of Biochemistry and Molecular Biology, Faculty of Biology, University of Bucharest, Bucharest, Romania
| | - Sami Gharbia
- Institute of Life Sciences, Vasile Goldis Western University of Arad, Arad, Romania
| | - Gisela Gaina
- Department of Biochemistry and Molecular Biology, Faculty of Biology, University of Bucharest, Bucharest, Romania
| | - Andreea Dudu
- Department of Biochemistry and Molecular Biology, Faculty of Biology, University of Bucharest, Bucharest, Romania
| | | | - Anca Hermenean
- Institute of Life Sciences, Vasile Goldis Western University of Arad, Arad, Romania
| | - Sergiu E Georgescu
- Department of Biochemistry and Molecular Biology, Faculty of Biology, University of Bucharest, Bucharest, Romania
| | - Marieta Costache
- Department of Biochemistry and Molecular Biology, Faculty of Biology, University of Bucharest, Bucharest, Romania
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Expression Characterization of Six Genes Possibly Involved in Gonad Development for Stellate Sturgeon Individuals ( Acipenser stellatus, Pallas 1771). Int J Genomics 2018; 2018:7835637. [PMID: 29785396 PMCID: PMC5896241 DOI: 10.1155/2018/7835637] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2017] [Revised: 12/12/2017] [Accepted: 03/11/2018] [Indexed: 02/04/2023] Open
Abstract
Nowadays, in sturgeon's aquaculture, there is a necessity for sex identification at early stages in order to increase the efficiency of this commercial activity. The basis for a correct identification is studying the different factors that influence the gonad development. The research has been directed towards molecular methods that have been employed with various degrees of success in identifying genes with different expression patterns between male and female sturgeons during their development stages. For the purpose of understanding the sexual development of 4-year-old stellate sturgeon (Acipenser stellatus) individuals, we have selected six genes (foxl2, cyp17a1, ar, dmrt1, sox9, and star). We analysed the gene expression of the selected genes for gonads, anal fin, liver, body kidney, and white muscle. The cyp17a1, ar, dmrt1, and sox9 genes have a significant higher expression in male gonads than in female gonads, while the data shows no significant differences in the expression of the investigated genes in the other organs. We investigate these genes to shed light on aquaculture sturgeon sexual development.
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Yom-Din S, Hollander-Cohen L, Aizen J, Boehm B, Shpilman M, Golan M, Hurvitz A, Degani G, Levavi-Sivan B. Gonadotropins in the Russian Sturgeon: Their Role in Steroid Secretion and the Effect of Hormonal Treatment on Their Secretion. PLoS One 2016; 11:e0162344. [PMID: 27622546 PMCID: PMC5021361 DOI: 10.1371/journal.pone.0162344] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2016] [Accepted: 08/22/2016] [Indexed: 11/24/2022] Open
Abstract
In the reproduction process of male and female fish, pituitary derived gonadotropins (GTHs) play a key role. To be able to specifically investigate certain functions of Luteinizing (LH) and Follicle stimulating hormone (FSH) in Russian sturgeon (Acipenser gueldenstaedtii; st), we produced recombinant variants of the hormones using the yeast Pichia pastoris as a protein production system. We accomplished to create in vitro biologically active heterodimeric glycoproteins consisting of two associated α- and β-subunits in sufficient quantities. Three dimensional modelling of both GTHs was conducted in order to study the differences between the two GTHs. Antibodies were produced against the unique β-subunit of each of the GTHs, in order to be used for immunohistochemical analysis and to develop an ELISA for blood and pituitary hormone quantification. This detection technique revealed the specific localization of the LH and FSH cells in the sturgeon pituitary and pointed out that both cell types are present in substantially higher numbers in mature males and females, compared to immature fish. With the newly attained option to prevent cross-contamination when investigating on the effects of GTH administration, we compared the steroidogeneic response (estradiol and 11-Keto testosterone (11-KT) in female and males, respectively) of recombinant stLH, stFSH, and carp pituitary extract in male and female sturgeon gonads at different developmental stages. Finally, we injected commercially available gonadotropin releasing hormones analog (GnRH) to mature females, and found a moderate effect on the development of ovarian follicles. Application of only testosterone (T) resulted in a significant increase in circulating levels of 11-KT whereas the combination of GnRH + T did not affect steroid levels at all. The response pattern for estradiol demonstrated a similar situation. FSH levels showed significant increases when GnRH + T was administered, while no changes were present in LH levels.
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Affiliation(s)
- Svetlana Yom-Din
- Department of Animal Sciences, The Robert H. Smith Faculty of Agriculture, Food and Environment, The Hebrew University of Jerusalem, Rehovot, 76100, Israel
| | - Lian Hollander-Cohen
- Department of Animal Sciences, The Robert H. Smith Faculty of Agriculture, Food and Environment, The Hebrew University of Jerusalem, Rehovot, 76100, Israel
| | - Joseph Aizen
- Department of Animal Sciences, The Robert H. Smith Faculty of Agriculture, Food and Environment, The Hebrew University of Jerusalem, Rehovot, 76100, Israel
| | - Benjamin Boehm
- Department of Animal Sciences, The Robert H. Smith Faculty of Agriculture, Food and Environment, The Hebrew University of Jerusalem, Rehovot, 76100, Israel
| | - Michal Shpilman
- Department of Animal Sciences, The Robert H. Smith Faculty of Agriculture, Food and Environment, The Hebrew University of Jerusalem, Rehovot, 76100, Israel
| | - Matan Golan
- Department of Animal Sciences, The Robert H. Smith Faculty of Agriculture, Food and Environment, The Hebrew University of Jerusalem, Rehovot, 76100, Israel
| | - Avshalom Hurvitz
- MIGAL Galilee Technology Center, PO Box 831, Kiryat Shmona, 10200, Israel
| | - Gad Degani
- MIGAL Galilee Technology Center, PO Box 831, Kiryat Shmona, 10200, Israel
| | - Berta Levavi-Sivan
- Department of Animal Sciences, The Robert H. Smith Faculty of Agriculture, Food and Environment, The Hebrew University of Jerusalem, Rehovot, 76100, Israel
- * E-mail:
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14
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Jin YH, Park JW, Kim JH, Kwon JY. Neurokinin B-related Peptide Suppresses the Expression of GnRH I, Kiss2 and tac3 in the Brain of Mature Female Nile tilapia Oreochromis niloticus. Dev Reprod 2016; 20:51-61. [PMID: 27294210 PMCID: PMC4899558 DOI: 10.12717/dr.2016.20.1.051] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Neurokinin B (NKB) and neurokinin B related peptide (NKBRP) belong to tachykinin peptide family. Theyact as a neurotransmitter and/or neuromodulator. Mutation of NKB and/or its cognate receptor, NK3R resulted in hypogonadotropic hypogonadism in mammals, implying a strong involvement of NKB/NK3R system in controlling mammalian reproduction. Teleosts possess NKBRP as well as NKB, but their roles in fish reproduction need to be clarified. In this study, NKB and NKBRP coding gene (tac3) was cloned from Nile tilapia and sequenced. Based on the sequence, Nile tilapia NKB and NKBRP peptide were synthesized and their biological potencies were tested in vitro pituitary culture. The synthetic NKBRP showed direct inhibitory effect on the expression of GTH subunits at the pituitary level. This inhibitory effect was confirmed in vivo by means of intraperitoneal (ip) injection of synthetic NKB and NKBRP to mature female tilapia (20 pmol/g body weight [BW]). Both NKB and NKBRP had no effect on the plasma level of sex steroids, E2 and 11-KT. However, NKBRP caused declines of expression level of GnRH I, Kiss2 and tac3 mRNAs in the brain while NKB seemed to have no distinct effect. These results indicate some inhibitory roles of NKBRP in reproduction of mature female Nile tilapia, although their exact functions are not clear at the moment.
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Affiliation(s)
- Ye Hwa Jin
- Dept. of Aquatic Life Medical Sciences, Sunmoon University, Asan 31460, Korea
| | - Jin Woo Park
- Marine Ecosystem and Biological Research Center, Korea Institute of Ocean Science & Technology, Ansan 15627, Korea
| | - Jung-Hyun Kim
- Dept. of Aquatic Life Medical Sciences, Sunmoon University, Asan 31460, Korea
| | - Joon Yeong Kwon
- Dept. of Aquatic Life Medical Sciences, Sunmoon University, Asan 31460, Korea
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15
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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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16
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Application of dopaminergic antagonist: Metoclopramide, in reproduction of crucian carp Carassius carassius (L.) under controlled conditions. Anim Reprod Sci 2015; 160:74-81. [DOI: 10.1016/j.anireprosci.2015.07.005] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2015] [Revised: 07/13/2015] [Accepted: 07/23/2015] [Indexed: 11/21/2022]
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17
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Jin YH, Park JW, Kim JH, Kwon JY. The Expression Pattern of Melatonin Receptor 1a Gene during Early Life Stages in the Nile tilapia (Oreochromis niloticus). Dev Reprod 2015; 17:45-53. [PMID: 25949120 PMCID: PMC4282221 DOI: 10.12717/dr.2013.17.1.045] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2013] [Revised: 03/01/2013] [Accepted: 03/11/2013] [Indexed: 11/20/2022]
Abstract
The action of melatonin within the body of animals is known to be mediated by melatonin receptors. Three different types of melatonin receptors have been identified so far in fish. However, which of these are specifically involved in puberty onset is not known in fish. We cloned and analyzed the sequence of melatonin receptor 1a (mel 1a) gene in Nile tilapia Oreochromis niloticus. In addition, we examined the tissue distribution of gene expressions for three types of receptors, mel 1a, 1b and lc and investigated which of them is involved in the onset of puberty by comparing their expression with that of gonadotropin-releasing hormone receptor I (GnRHr I) gene using quantitative real-time PCR from 1 week post hatch (wph) to 24 wph. The mel 1a gene of Nile tilapia consisted of two exons and one bulky intron between them. Mel 1a gene was found to be highly conserved gene showing high homology with the corresponding genes from different teleost. All three types of melatonin receptor genes were expressed in the brain, eyes and ovary in common. Expression of mel 1a gene was the most abundant and ubiquitous among 3 receptors in the brain, liver, gill, ovary, muscle, eye, heart, intestine, spleen and kidney. Mel 1b and mel 1c genes were, however, expressed in fewer tissues at low level. During the development post hatch, expressions of both mel 1a and GnRHr I genes significantly increased at 13 wph which was close to the putative timing of puberty onset in this species. These results suggest that among three types of receptors mel 1a is most likely associated with the action of melatonin in the onset of puberty in Nile tilapia.
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Affiliation(s)
- Ye Hwa Jin
- Department of Aquatic Life Medical Sciences, Sunmoon University, Asan 336-708, Korea
| | - Jin Woo Park
- Department of Aquatic Life Medical Sciences, Sunmoon University, Asan 336-708, Korea
| | - Jung-Hyun Kim
- Department of Aquatic Life Medical Sciences, Sunmoon University, Asan 336-708, Korea
| | - Joon Yeong Kwon
- Department of Aquatic Life Medical Sciences, Sunmoon University, Asan 336-708, Korea
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18
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Chabbi A, Ganesh CB. Evidence for the involvement of dopamine in stress-induced suppression of reproduction in the cichlid fish Oreochromis mossambicus. J Neuroendocrinol 2015; 27:343-56. [PMID: 25712855 DOI: 10.1111/jne.12269] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/16/2014] [Revised: 02/02/2015] [Accepted: 02/19/2015] [Indexed: 01/23/2023]
Abstract
In the present study, we examined whether stress-induced suppression of reproduction is mediated through the catecholaminergic neurotransmitter dopamine (DA) in the female cichlid fish Oreochromis mossambicus. In the first experiment, application of antibody against tyrosine hydroxylase (TH; a marker for DA) in brain sections revealed the presence of intensely stained TH immunoreactive cells in the preoptic area (POA) and nucleus preopticus (NPO) during the previtellogenic phase. These cells showed weak immunoreactivity during the vitellogenic and prespawning phases concomitant with darkly stained luteinising hormone (LH) immunoreactive content in the proximal pars distalis (PPD) of the pituitary gland and fully ripened follicles (stage V) in the ovary of control fish. However, in fish exposed to aquacultural stressors, TH secreting cells remained intensely stained in POA and NPO regions during the prespawning phase, indicating increased synthetic and secretory activity, which was reflected by a significantly higher DA content compared to controls. Increased DA activity as a result of stress was associated with a decrease in the LH immunoreactive content in the PPD and an absence of stage V follicles in the ovary. In the second experiment, administration of DA caused effects similar to those in stressed fish, whereas DA receptor antagonist domperidone (DOM) treatment significantly increased the LH content in the PPD and the number of stage V follicles in unstressed fish. On the other hand, treatment of stressed fish with DOM resulted in dark accumulations of LH immunoreactive content in the PPD accompanied by the presence of stage V follicles in the ovary. Taken together, these results suggest an additional pathway for the inhibitory effects of stress through dopaminergic neurones along the reproductive axis.
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Affiliation(s)
- A Chabbi
- Neuroendocrinology Research Lab, Department of Studies in Zoology, Karnatak University, Dharwad, Karnataka, India
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19
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Crago J, Schlenk D. The effect of bifenthrin on the dopaminergic pathway in juvenile rainbow trout (Oncorhynchus mykiss). AQUATIC TOXICOLOGY (AMSTERDAM, NETHERLANDS) 2015; 162:66-72. [PMID: 25781393 DOI: 10.1016/j.aquatox.2015.03.005] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/08/2015] [Revised: 03/05/2015] [Accepted: 03/06/2015] [Indexed: 05/27/2023]
Abstract
Bifenthrin is a type I pyrethroid pesticide, which has been shown to increase plasma estrogen concentrations in several fish models. The mechanism of action by which bifenthrin alters 17β-estradiol (E2) is unclear. E2 biosynthesis is regulated through pituitary follicle stimulating hormone, which is directly controlled by hypothalamic gonadotropin releasing hormone (GnRH2). Since dopaminergic signaling significantly influences GnRH2 release in fish, the goal of the study was to determine the effect of a 96 h and 2 weeks exposure to bifenthrin on dopaminergic signaling in juvenile rainbow trout (Oncorhynchus mykiss) (RT). Our results indicated that a decrease in dopamine receptor 2A (DR2A) expression was associated with a trend toward an increase in plasma E2 following exposure at 96 h and 2 weeks, and a significant increase in the relative expression of vitellogenin mRNA at 2 weeks. DR2A mRNA expression decreased 426-fold at 96 h and 269-fold at 2 weeks in the brains of 1.5 ppb (3.55 pM) bifenthrin treated RT. There was an increase in tyrosine hydroxylase transcript levels at 96 h, which is indicative of dopamine production in the brains of the 1.5 ppb (3.55 pM) bifenthrin treated RT. A significant increase in the relative expression of GnRH2 was observed at 96 h but a significant decrease was noted after 2 weeks exposure indicating potential feedback loop activation. These results indicate that the estrogenic-effects of bifenthrin may result in part from changes in signaling within the dopaminergic pathway, but that other feedback pathways may also be involved.
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Affiliation(s)
- Jordan Crago
- School of Freshwater Sciences, University of Wisconsin, Milwaukee, Milwaukee, WI 53204, USA.
| | - Daniel Schlenk
- Department of Environment Studies, University California-Riverside, Riverside, CA 92521, USA
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20
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Breton TS, DiMaggio MA, Sower SA, Berlinsky DL. Brain aromatase (cyp19a1b) and gonadotropin releasing hormone (gnrh2 and gnrh3) expression during reproductive development and sex change in black sea bass (Centropristis striata). Comp Biochem Physiol A Mol Integr Physiol 2015; 181:45-53. [DOI: 10.1016/j.cbpa.2014.11.020] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2014] [Revised: 11/21/2014] [Accepted: 11/25/2014] [Indexed: 10/24/2022]
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21
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Badruzzaman M, Imamura S, Takeuchi Y, Ikegami T, Takemura A. Effects of neurotoxin 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) treatment on ovarian development of the sapphire devil, Chrysiptera cyanea. FISH PHYSIOLOGY AND BIOCHEMISTRY 2015; 41:61-71. [PMID: 25362562 DOI: 10.1007/s10695-014-0006-9] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/13/2014] [Accepted: 10/20/2014] [Indexed: 06/04/2023]
Abstract
In the neuroendocrine system controlling fish reproduction, dopamine (DA) acts as a gonadotropin inhibitory factor and plays a role in regulating gonadal development of certain species. The present study examined the effects of chemical destruction of dopaminergic neurons in the brain on DA production and ovarian development in the sapphire devil Chrysiptera cyanea, a reef-associated damselfish. The avidin-biotin-peroxidase complex method using an antibody against tyrosine hydroxylase (TH), a critical enzyme in the DA synthesis pathway, identified a population of dopaminergic neurons with somata in the anteroventral preoptic nucleus of the diencephalon and fibers terminating in the proximal pars distalis of the pituitary. Maintaining fish in seawater containing 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) at 0.02 and 0.2 µg/mL for 2 days resulted in decreases in DA, 3,4-dihydroxyphenylacetic acid (DOPAC; DA metabolite), and DA metabolic rate in the whole brain. The number of TH-positive neurons in the diencephalon decreased after 0.02 µg/mL MPTP treatment for 2 days. These results suggest that MPTP treatment destroys TH-positive neurons in the diencephalon, thereby decreasing the synthesis and release of DA from the brain. This treatment rescued ovarian development in fish with artificially retracted ovaries during the spawning season. The gonadosomatic index of MPTP-treated fish 5 and 7 days after treatment was significantly higher than that of control fish. Oocytes in the vitellogenic stages were observed in the ovaries of MPTP-treated fish, but not in control fish. These results suggest that DA in the brain drives ovarian development in the sapphire devil.
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Affiliation(s)
- Muhammad Badruzzaman
- Department of Chemistry, Biology and Marine Science, University of the Ryukyus, 1 Senbaru, Nishihara, Okinawa, 903-0213, Japan
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Biran J, Golan M, Mizrahi N, Ogawa S, Parhar IS, Levavi-Sivan B. Direct regulation of gonadotropin release by neurokinin B in tilapia (Oreochromis niloticus). Endocrinology 2014; 155:4831-42. [PMID: 25211586 DOI: 10.1210/en.2013-2114] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Neurokinin B (NKB) was recently identified as a key regulator of reproduction in mammals and fish. Fish were found to possess a specific novel neurokinin termed NKF. To study the role of NKB/NKF in the regulation of fish reproduction and to investigate the role of NKB/NKF and their receptors in the piscine pituitary, we have identified the NKB/tachikinin 3 receptor (tac3r) system in tilapia. Bioinformatics and phylogenetic analyses have demonstrated that the tilapia holds 1 putative tac3 gene and 2 NKB receptor genes (tac3ra and tac3rb) that clustered with other piscine Tac3 and NKB receptor lineages. Furthermore, we found that in African cichlids, NKB peptides differ from other vertebrate NKBs in their C-terminal sequence, possessing isoleucine instead of valine as the X in the NKB FXGLM-NH2-terminal consensus sequence. Signal transduction analysis demonstrated that tilapia NKB (tiNKB), tiNKF, and human NKB activated both CRE-luc and SRE-luc transcriptional activity of both tilapia and human NKB receptors. Two hours after ip injection of tiNKB, the plasma levels of both FSH and LH were increased, whereas tiNKF was more effective in increasing LH levels. However, tiNKB was more effective than tiNKF in increasing both FSH and LH from tilapia pituitary dispersed cells. Using in situ hybridization and fluorescent immunohistochemistry, we have shown that LH cells possess tac3, tac3ra, and tac3rb mRNAs, whereas FSH cells possess mainly tac3rb and tac3ra and tac3 to a much lesser extent. These results suggest that the members of the NKB/tac3r system may serve as paracrine/autocrine regulators of gonadotropin release in fish pituitary.
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Affiliation(s)
- Jakob Biran
- Department of Animal Sciences (J.B., M.G., N.M., B.L.-S.), The Robert H. Smith Faculty of Agriculture, Food, and Environment, Hebrew University of Jerusalem, Rehovot 76100, Israel; and Brain Research Institute (S.O., I.S.P.), Monash University Sunway Campus, Jalan Lagoon Selatan, Bandar Sunway, Selangor 46150, Malaysia
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Shpilman M, Hollander-Cohen L, Ventura T, Gertler A, Levavi-Sivan B. Production, gene structure and characterization of two orthologs of leptin and a leptin receptor in tilapia. Gen Comp Endocrinol 2014; 207:74-85. [PMID: 24852346 DOI: 10.1016/j.ygcen.2014.05.006] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/19/2014] [Revised: 05/04/2014] [Accepted: 05/08/2014] [Indexed: 12/18/2022]
Abstract
Full-length cDNA encoding two leptin sequences (tLepA and tLepB) and one leptin receptor sequence (tLepR) were identified in tilapia (Oreochromis niloticus). The full-length cDNA of tLepR was 3423bp, encoding a protein of 1140 amino acid (aa) which contained all functionally important domains conserved among vertebrate leptin receptors. The cDNAs of tLepA and tLepB were 486bp and 459bp in length, encoding proteins of 161 aa and 152 aa, respectively. Modeling the three-dimensional structures of tLepA and tLepB predicted strong conservation of tertiary structure with that of human leptin, comprised of four helixes. Using synteny, the tLeps were found near common genes, such as IMPDH1 and LLRC4. The cDNA for tLepA and tLepB was cloned and synthetic cDNA optimized for expression in Escherichia coli was prepared according to the cloned sequence. The tLepA- and tLepB-expressing plasmids were transformed into E. coli and expressed as recombinant proteins upon induction with nalidixic acid, found almost entirely in insoluble inclusion bodies (IBs). The proteins were solubilized, refolded and purified to homogeneity by anion-exchange chromatography. In the case of tLepA, the fraction eluted contained a mixture of monomers and dimers. The purified tLepA and tLepB monomers and tLepA dimer showed a single band of ∼15kDa on an SDS-polyacrylamide gel in the presence of reducing agent, whereas the tLepA dimer showed one band of ∼30kDa in the absence of reducing agent, indicating its formation by S-S bonds. The three tLeps were biologically active in promoting proliferation of BAF/3 cells stably transfected with the long form of human leptin receptor (hLepR), but their activity was four orders of magnitude lower than that of mammalian leptin. Furthermore, the three tLeps were biologically active in promoting STAT-LUC activation in COS7 cells transfected with the identified tLepR but not in cells transfected with hLepR. tLepA was more active than tLepB. Low or no activity likely resulted from low identity (9-22%) to mammalian leptins. In an in vivo experiment in which tilapia were fed ad libitum or fasted, there was no significant difference in the expressions of tLepA, tLepB or tLepR in the brain between the two groups examined both by real-time PCR and RNA next generation sequencing. In conclusion, in the present report we show novel, previously unknown sequences of tilapia leptin receptor and two leptins and prepare two biologically active recombinant leptin proteins.
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Affiliation(s)
- Michal Shpilman
- Department of Animal Sciences, The Robert H. Smith Faculty of Agriculture, Food, and Environment, Hebrew University of Jerusalem, Rehovot 76100, Israel
| | - Lian Hollander-Cohen
- Department of Animal Sciences, The Robert H. Smith Faculty of Agriculture, Food, and Environment, Hebrew University of Jerusalem, Rehovot 76100, Israel
| | - Tomer Ventura
- Faculty of Science, Health, Education and Engineering, GeneCology Research Centre, University of the Sunshine Coast, Queensland, Australia
| | - Arieh Gertler
- Institute of Biochemistry, Food Science and Nutrition, The Robert H. Smith Faculty of Agriculture, Food, and Environment, Hebrew University of Jerusalem, Rehovot 76100, Israel
| | - Berta Levavi-Sivan
- Department of Animal Sciences, The Robert H. Smith Faculty of Agriculture, Food, and Environment, Hebrew University of Jerusalem, Rehovot 76100, Israel.
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Jeng SR, Yueh WS, Pen YT, Lee YH, Chen GR, Dufour S, Chang CF. Neuroendocrine gene expression reveals a decrease in dopamine D2B receptor with no changes in GnRH system during prepubertal metamorphosis of silvering in wild Japanese eel. Gen Comp Endocrinol 2014; 206:8-15. [PMID: 25125083 DOI: 10.1016/j.ygcen.2014.08.001] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/28/2014] [Revised: 07/20/2014] [Accepted: 08/05/2014] [Indexed: 11/21/2022]
Abstract
Silvering is a prepubertal metamorphosis preparing the eel to the oceanic reproductive migration. A moderate gonad development occurs during this metamorphosis from the sedentary yellow stage to the migratory silver stage. The aim of this study was to elucidate the molecular aspects of various endocrine parameters of BPG axis at different ovarian developmental stages in wild yellow and silver female Japanese eels. The GSI of the sampled female eels ranged between 0.18 and 2.3%, corresponding to yellow, pre-silver and silver stages. Gonad histology showed changes from previtellogenic oocytes in yellow eels to early vitellogenic oocytes in silver eels. Both serum E2 and T concentrations significantly increased with ovarian development indicating a significant activation of steroidogenesis during silvering. In agreement with previous studies, significant increases in pituitary gonadotropin beta subunits FSH-β and LH-β transcripts were also measured by qPCR, supporting that the activation of pituitary gonadotropin expression is likely responsible for the significant ovarian development observed during silvering. We investigated for the first time the possible brain neuroendocrine mechanisms involved in the activation of the pituitary gonadotropic function during silvering. By analyzing the expression of genes representative of the stimulatory GnRH control and the inhibitory dopaminergic control. The transcript levels of mGnRH and the three GnRH receptors did not change in the brain and pituitary between yellow and silver stages, suggesting that gene expression of the GnRH system is not significantly activated during silvering. The brain transcript levels of tyrosine hydroxylase, limiting enzyme of DA synthesis did not change during silvering, indicating that the DA synthesis activity was maintained. In contrast, a significant decrease in DA-D2B receptor expression in the forebrain and pituitary was observed, with no changes in DA-D2A receptor. The decrease in the pituitary expression of DA-D2BR during silvering would allow a reduced inhibitory effect of DA. We may raise the hypothesis that this regulation of D2BR gene expression is one of the neuroendocrine mechanisms involved in the slight activation of the pituitary gonadotropin and gonadal activity that occur at silvering.
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Affiliation(s)
- Shan-Ru Jeng
- Department of Aquaculture, National Kaohsiung Marine University, Kaohsiung 811, Taiwan.
| | - Wen-Shiun Yueh
- Department of Aquaculture, National Kaohsiung Marine University, Kaohsiung 811, Taiwan
| | - Yi-Ting Pen
- Department of Aquaculture, National Kaohsiung Marine University, Kaohsiung 811, Taiwan
| | - Yan-Horn Lee
- Tungkang Biotechnology Research Center, Fisheries Research Institute, Council of Agriculture, Tungkang 928, Taiwan
| | - Guan-Ru Chen
- Freshwater Aquaculture Research Center, Fisheries Research Institute, Council of Agriculture, Lukang 505, Taiwan
| | - Sylvie Dufour
- Muséum National d'Histoire Naturelle, Sorbonne Universités, Research Unit BOREA, Biology of Aquatic Organisms and Ecosystems, CNRS 7208 - IRD207 - UPMC - UCBN, 75231 Paris Cedex 05, France
| | - Ching-Fong Chang
- Department of Aquaculture, National Taiwan Ocean University, Keelung 202, Taiwan; Center of Excellence for the Oceans, National Taiwan Ocean University, Keelung 202, Taiwan.
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Kalamarz-Kubiak H, Meiri-Ashkenazi I, Kleszczyńska A, Rosenfeld H. In vitro effect of cortisol and urotensin I on arginine vasotocin and isotocin secretion from pituitary cells of gilthead sea bream Sparus aurata. JOURNAL OF FISH BIOLOGY 2014; 84:448-458. [PMID: 24405471 DOI: 10.1111/jfb.12297] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/02/2013] [Accepted: 11/13/2013] [Indexed: 06/03/2023]
Abstract
This study aimed at determining whether in vitro secretion of two neuropeptides, arginine vasotocin (AVT) and isotocin (IT), from pituitary cells of gilthead sea bream Sparus aurata was affected by cortisol and urotensin (UI). Pituitary cells were exposed to 1·4 × 10(-8) , 1·4 × 10(-7) and 0·4 × 10(-6) M cortisol and 10(-12) , 10(-10) and 10(-8) M UI for 6, 24 and 48 h, respectively. AVT and IT contents were determined in the culture media by high-performance liquid chromatography (HPLC). An increase in AVT secretion and a decrease in IT secretion were observed at all cortisol doses. UI increased AVT secretion after 6 h of incubation at all doses. After 24 h, however, only the highest dose of UI still displayed an effect. IT secretion was not influenced by UI. It was thus demonstrated that cortisol does influence AVT and IT secretion from S. aurata pituitary cells, while UI regulates AVT secretion, as a component of hypothalamic-pituitary-interrenal (HPI) axis in this species.
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Affiliation(s)
- H Kalamarz-Kubiak
- Department of Genetics and Marine Biotechnology, Institute of Oceanology of Polish Academy of Sciences, Powstańców Warszawy 55, 81-712 Sopot, Poland
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26
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Maruska KP, Fernald RD. Social regulation of male reproductive plasticity in an African cichlid fish. Integr Comp Biol 2013; 53:938-50. [PMID: 23613320 PMCID: PMC3836007 DOI: 10.1093/icb/ict017] [Citation(s) in RCA: 66] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Social interactions with the outcome of a position in a dominance hierarchy can have profound effects on reproductive behavior and physiology, requiring animals to integrate environmental information with their internal physiological state; but how is salient information from the animal's dynamic social environment transformed into adaptive behavioral, physiological, and molecular-level changes? The African cichlid fish, Astatotilapia burtoni, is ideally suited to understand socially controlled reproductive plasticity because activity of the male reproductive (brain-pituitary-gonad) axis is tightly linked to social status. Males form hierarchies in which a small percentage of brightly colored dominant individuals have an active reproductive axis, defend territories, and spawn with females, while the remaining males are subordinate, drably colored, do not hold a territory, and have a suppressed reproductive system with minimal opportunities for spawning. These social phenotypes are plastic and quickly reversible, meaning that individual males may switch between dominant and subordinate status multiple times within a lifetime. Here, we review the rapid and remarkable plasticity that occurs along the entire reproductive axis when males rise in social rank, a transition that has important implications for the operational sex ratio of the population. When males rise in rank, transformations occur in the brain, pituitary, circulation, and testes over short time-scales (minutes to days). Changes are evident in overt behavior, as well as modifications at the physiological, cellular, and molecular levels that regulate reproductive capacity. Widespread changes triggered by a switch in rank highlight the significance of external social information in shaping internal physiology and reproductive competence.
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Affiliation(s)
- Karen P. Maruska
- *Department of Biology, Stanford University, Stanford, CA 94305, USA; Department of Biological Sciences, Louisiana State University, Baton Rouge, LA 70803, USA
| | - Russell D. Fernald
- *Department of Biology, Stanford University, Stanford, CA 94305, USA; Department of Biological Sciences, Louisiana State University, Baton Rouge, LA 70803, USA
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27
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Golan M, Levavi-Sivan B. Social dominance in tilapia is associated with gonadotroph hyperplasia. Gen Comp Endocrinol 2013; 192:126-35. [PMID: 23660448 DOI: 10.1016/j.ygcen.2013.04.032] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/17/2013] [Revised: 04/20/2013] [Accepted: 04/24/2013] [Indexed: 01/01/2023]
Abstract
Tilapias are emerging as one of the most important fish in worldwide aquaculture and are also widely used as model fish in the study of reproduction and behavior. During the reproductive season, male tilapia are highly territorial and form spawning pits in which the dominant males court and spawn with available females. Non-territorial males stand a much lower chance of reproducing. Using transgenic tilapia in which follicle stimulating hormone (FSH) gonadotrophs were fluorescently labeled with enhanced green fluorescent protein (EGFP), we studied the effect of social dominance on the hormonal profile and pituitary cell populations in dominant and non-dominant males. Immunofluorescence studies showed that FSH-EGFP-transgenic fish reliably express EGFP in FSH-secreting cells. EGFP expression pattern differed from that of luteinizing hormone. Dominant males had larger gonads as well as higher levels of androgens and gonadotropins in the plasma. Pituitaries of dominant males exhibited higher gonadotropin content and gene expression. Flow cytometry revealed pituitary hyperplasia as well as FSH cell hyperplasia and increased granulation. Taken together, these findings suggest that gonadotroph hyperplasia as well as increased production by individual cells underlie the increased reproductive activity of dominant tilapia males.
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Affiliation(s)
- Matan Golan
- 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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28
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Fernandes AFA, Alvarenga ÉR, Oliveira DAA, Aleixo CG, Prado SA, Luz RK, Sarmento NLAF, Teixeira EA, Luz MR, Turra EM. Production of oocytes of Nile tilapia (Oreochromis niloticus) for in vitro fertilization via hormonal treatments. Reprod Domest Anim 2013; 48:1049-55. [PMID: 23834584 DOI: 10.1111/rda.12212] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2013] [Accepted: 06/04/2013] [Indexed: 11/30/2022]
Abstract
Only a few studies have described hormonal treatments for induction of synchronicity and gamete collection in Nile tilapia (Oreochromis niloticus), both important for assortative matings in breeding programmes and essential for polyploidy technologies. In this study, we compared the effectiveness of carp pituitary extract (CPE), Nile tilapia pituitary extract (TPE), human chorionic gonadotropin (hCG) and gonadotropin-releasing hormone (GnRH) protocols on the induction of spawning and egg production in Nile tilapia. Among the hormonal treatments analysed, only hCG was effective for producing viable gametes for in vitro fertilization. To verify the viability of this hormonal treatment, hCG was tested using different doses (1000, 2000, 3000, 4000 and 5000 IU/kg) in a large number of females (208 animals) from two Nile tilapia lines. The results indicated that hCG doses between 1000 and 5000 IU/kg could be used to induce final oocyte maturation in Nile tilapia with collection of stripped oocytes. This is the first study to report differential reproductive responses to hormonal treatment between tilapia lines: line 1 was more efficient at producing eggs and post-hatching larvae after hCG induction than line 2. In conclusion, we demonstrated that the hCG protocol may be applied on a large scale to induce final oocyte maturation in Nile tilapia. The development of a protocol for in vitro fertilization in Nile tilapia may aid in breeding programmes and biotechnological assays for the development of genetically modified lines of Nile tilapia.
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Affiliation(s)
- A F A Fernandes
- Laboratório de Aquacultura (LAQUA), Escola de Veterinária da Universidade Federal de Minas Gerais, Belo Horizonte, Brazil
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29
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Peñaranda DS, Mazzeo I, Hildahl J, Gallego V, Nourizadeh-Lillabadi R, Pérez L, Asturiano JF, Weltzien FA. Molecular characterization of three GnRH receptor paralogs in the European eel, Anguilla anguilla: tissue-distribution and changes in transcript abundance during artificially induced sexual development. Mol Cell Endocrinol 2013; 369:1-14. [PMID: 23416230 DOI: 10.1016/j.mce.2013.01.025] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/18/2012] [Revised: 01/25/2013] [Accepted: 01/29/2013] [Indexed: 11/17/2022]
Abstract
Gonadotropin-releasing hormone receptor (GnRH-R) activation stimulates synthesis and release of gonadotropins in the vertebrate pituitary and also mediates other processes both in the brain and in peripheral tissues. To better understand the differential function of multiple GnRH-R paralogs, three GnRH-R genes (gnrhr1a, 1b, and 2) were isolated and characterized in the European eel. All three gnrhr genes were expressed in the brain and pituitary of pre-pubertal eels, and also in several peripheral tissues, notably gills and kidneys. During hormonally induced sexual maturation, pituitary expression of gnrhr1a (female) and gnrhr2 (male and female) was up-regulated in parallel with gonad development. In the brain, a clear regulation during maturation was seen only for gnrhr2 in the midbrain, with highest levels recorded during early vitellogenesis. These data suggest that GnRH-R2 is the likely hypophysiotropic GnRH-R in male eel, while both GnRH-R1a and GnRH-R2 seems to play this role in female eels.
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Affiliation(s)
- David S Peñaranda
- Grupo de Acuicultura y Biodiversidad, Instituto de Ciencia y Tecnología Animal, Universitat Politècnica de València, Valencia, Spain
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30
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Gopurappilly R, Ogawa S, Parhar IS. Functional significance of GnRH and kisspeptin, and their cognate receptors in teleost reproduction. Front Endocrinol (Lausanne) 2013; 4:24. [PMID: 23482509 PMCID: PMC3591744 DOI: 10.3389/fendo.2013.00024] [Citation(s) in RCA: 57] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/15/2012] [Accepted: 02/22/2013] [Indexed: 12/18/2022] Open
Abstract
Guanine nucleotide binding protein (G-protein)-coupled receptors (GPCRs) are eukaryotic transmembrane proteins found in all living organisms. Their versatility and roles in several physiological processes make them the single largest family of drug targets. Comparative genomic studies using various model organisms have provided useful information about target receptors. The similarity of the genetic makeup of teleosts to that of humans and other vertebrates aligns with the study of GPCRs. Gonadotropin-releasing hormone (GnRH) represents a critical step in the reproductive process through its cognate GnRH receptors (GnRHRs). Kisspeptin (Kiss1) and its cognate GPCR, GPR54 (=kisspeptin receptor, Kiss-R), have recently been identified as a critical signaling system in the control of reproduction. The Kiss1/Kiss-R system regulates GnRH release, which is vital to pubertal development and vertebrate reproduction. This review highlights the physiological role of kisspeptin-Kiss-R signaling in the reproductive neuroendocrine axis in teleosts through the modulation of GnRH release. Moreover, we also review the recent developments in GnRHR and Kiss-R with respect to their structural variants, signaling mechanisms, ligand interactions, and functional significance. Finally, we discuss the recent progress in identifying many teleost GnRH-GnRHR and kisspeptin-Kiss-R systems and consider their physiological significance in the control of reproduction.
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Affiliation(s)
- Renjitha Gopurappilly
- Brain Research Institute, School of Medicine and Health Sciences, Monash University Sunway CampusSelangor, Malaysia
| | - Satoshi Ogawa
- Brain Research Institute, School of Medicine and Health Sciences, Monash University Sunway CampusSelangor, Malaysia
| | - Ishwar S. Parhar
- Brain Research Institute, School of Medicine and Health Sciences, Monash University Sunway CampusSelangor, Malaysia
- *Correspondence: Ishwar S. Parhar, Brain Research Institute, School of Medicine and Health Sciences, Monash University Sunway Campus, Petaling Jaya 46150, Selangor, Malaysia. e-mail:
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31
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Abstract
In the course of evolution, social behavior has been a strikingly potent selective force in shaping brains to control action. Physiological, cellular, and molecular processes reflect this evolutionary force, particularly in the regulation of reproductive behavior and its neural circuitry. Typically, experimental analysis is directed at how the brain controls behavior, but the brain is also changed by behavior over evolution, during development, and through its ongoing function. Understanding how the brain is influenced by behavior offers unusual experimental challenges. General principles governing the social regulation of the brain are most evident in the control of reproductive behavior. This is most likely because reproduction is arguably the most important event in an animal's life and has been a powerful and essential selective force over evolution. Here I describe the mechanisms through which behavior changes the brain in the service of reproduction using a teleost fish model system.
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Affiliation(s)
- Russell D Fernald
- Biology Department, Stanford University, Stanford, California 94305, USA.
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32
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Popesku JT, Martyniuk CJ, Trudeau VL. Meta-type analysis of dopaminergic effects on gene expression in the neuroendocrine brain of female goldfish. Front Endocrinol (Lausanne) 2012; 3:130. [PMID: 23130016 PMCID: PMC3487223 DOI: 10.3389/fendo.2012.00130] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/04/2012] [Accepted: 10/12/2012] [Indexed: 12/14/2022] Open
Abstract
Dopamine (DA) is a major neurotransmitter important for neuroendocrine control and recent studies have described genomic signaling pathways activated and inhibited by DA agonists and antagonists in the goldfish brain. Here we perform a meta-type analysis using microarray datasets from experiments conducted with female goldfish to characterize the gene expression responses that underlie dopaminergic signaling. Sexually mature, pre-spawning [gonadosomatic index (GSI) = 4.5 ± 1.3%] or sexually regressing (GSI = 3 ± 0.4%) female goldfish (15-40 g) injected intraperitoneally with either SKF 38393, LY 171555, SCH 23390, sulpiride, or a combination of 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine and α-methyl-p-tyrosine. Microarray meta-type analysis identified 268 genes in the telencephalon and hypothalamus as having reciprocal (i.e., opposite between agonism and antagonism/depletion) fold change responses, suggesting that these transcripts are likely targets for DA-mediated regulation. Noteworthy genes included ependymin, vimentin, and aromatase, genes that support the significance of DA in neuronal plasticity and tissue remodeling. Sub-network enrichment analysis (SNEA) was used to identify common gene regulators and binding proteins associated with the differentially expressed genes mediated by DA. SNEA analysis identified gene expression targets that were related to three major categories that included cell signaling (STAT3, SP1, SMAD, Jun/Fos), immune response (IL-6, IL-1β, TNFs, cytokine, NF-κB), and cell proliferation and growth (IGF1, TGFβ1). These gene networks are also known to be associated with neurodegenerative disorders such as Parkinsons' disease, well-known to be associated with loss of dopaminergic neurons. This study identifies genes and networks that underlie DA signaling in the vertebrate CNS and provides targets that may be key neuroendocrine regulators. The results provide a foundation for future work on dopaminergic regulation of gene expression in fish model systems.
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Affiliation(s)
- Jason T. Popesku
- Centre for Advanced Research in Environmental Genomics, Department of Biology, University of OttawaOttawa, ON, Canada
- *Correspondence: Jason T. Popesku, Centre for Advanced Research in Environmental Genomics, Department of Biology, University of Ottawa, Ottawa, ON, Canada K1N 6N5. e-mail: ; Vance L. Trudeau, Department of Biology, University of Ottawa, Room 160, Gendron Hall, 30 Marie Curie, Ottawa, ON, Canada K1N 6N5. e-mail:
| | - Christopher J. Martyniuk
- Canadian Rivers Institute and Department of Biology, University of New BrunswickSaint John, NB, Canada
| | - Vance L. Trudeau
- Centre for Advanced Research in Environmental Genomics, Department of Biology, University of OttawaOttawa, ON, Canada
- *Correspondence: Jason T. Popesku, Centre for Advanced Research in Environmental Genomics, Department of Biology, University of Ottawa, Ottawa, ON, Canada K1N 6N5. e-mail: ; Vance L. Trudeau, Department of Biology, University of Ottawa, Room 160, Gendron Hall, 30 Marie Curie, Ottawa, ON, Canada K1N 6N5. e-mail:
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33
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Maruska KP, Fernald RD. Social Regulation of Gene Expression in the Hypothalamic-Pituitary-Gonadal Axis. Physiology (Bethesda) 2011; 26:412-23. [DOI: 10.1152/physiol.00032.2011] [Citation(s) in RCA: 97] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
Abstract
Reproduction is a critically important event in every animals' life and in all vertebrates is controlled by the brain via the hypothalamic-pituitary-gonadal (HPG) axis. In many species, this axis, and hence reproductive fitness, can be profoundly influenced by the social environment. Here, we review how the reception of information in a social context causes genomic changes at each level of the HPG axis.
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Affiliation(s)
- Karen P. Maruska
- Department of Biology, Stanford University, Stanford, California
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34
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Popesku JT, Mennigen JA, Chang JP, Trudeau VL. Dopamine D1 receptor blockage potentiates AMPA-stimulated luteinising hormone release in the goldfish. J Neuroendocrinol 2011; 23:302-9. [PMID: 21276102 DOI: 10.1111/j.1365-2826.2011.02114.x] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Previous microarray analyses of the goldfish hypothalamus led us to hypothesise that dopamine could potentially inhibit the excitatory effects of glutamate on luteinising hormone (LH). Post-spawning female goldfish were pre-treated (-4.5 h) with either saline (C; control), SCH 23390 (S; D(1) -receptor antagonist) or sulpiride (L; D(2) -receptor antagonist), followed by an i.p. injection, at -0.5 h, of saline or the glutamate agonist AMPA (A, SA or LA). Blood, hypothalamus and telencephalon tissues were collected. Serum LH was not affected in the S, L, A, or LA groups relative to control as determined by radioimmunoassay. The SA group, however, showed a 289% (P<0.0005) increase in serum LH compared to either treatment alone or control. Real-time reverse transcriptase-polymerase chain reaction identified the mRNAs for ionotropic (Gria2a, Gria4) glutamate receptor subunits, activin βa, isotocin, and cGnRH-II as being significantly affected by some of the treatments. The same experiment conducted with sexually-regressed female fish showed a very different LH profile, indicating that this mechanism is seasonally-dependent. We also show that i.p. injection of 1 μg/g isotocin was able to increase LH levels by 167% in sexually regressed female fish relative to controls. Taken together, these results demonstrate that blockage of the D(1) receptor primes post-spawning goldfish for AMPA-stimulated LH release, and provides further insights into the central regulation of reproduction.
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Affiliation(s)
- J T Popesku
- Centre for Advanced Research in Environmental Genomics (CAREG), Department of Biology, University of Ottawa, Ottawa, Canada
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35
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Maruska KP, Levavi-Sivan B, Biran J, Fernald RD. Plasticity of the reproductive axis caused by social status change in an african cichlid fish: I. Pituitary gonadotropins. Endocrinology 2011; 152:281-90. [PMID: 21068157 PMCID: PMC3219043 DOI: 10.1210/en.2010-0875] [Citation(s) in RCA: 57] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Abstract
Social position in a dominance hierarchy is often tightly coupled with fertility. Consequently, an animal that can recognize and rapidly take advantage of an opportunity to rise in rank will have a reproductive advantage. Reproduction in all vertebrates is controlled by the brain-pituitary-gonad axis, and in males of the African cichlid fish Astatotilapia burtoni, GnRH1 neurons at the apex of this axis are under social control. However, little is known about how quickly social information is transformed into functional reproductive change, or about how socially controlled changes in GnRH1 neurons influence downstream actions of the brain-pituitary-gonad axis. We created an opportunity for reproductively suppressed males to ascend in status and then measured how quickly the perception of this opportunity caused changes in mRNA and protein levels of the pituitary gonadotropins. mRNA levels of the β-subunits of LH and FSH rose rapidly in the pituitary 30 min after suppressed males perceived an opportunity to ascend. In contrast, mRNA levels of GnRH receptor-1 remained unchanged during social transition but were higher in stable dominant compared with subordinate males. In the circulation, levels of both LH and FSH were also quickly elevated. There was a positive correlation between mRNA in the pituitary and circulating protein levels for LH and FSH, and both gonadotropins were positively correlated with plasma 11-ketotestosterone. Our results show that the pituitary is stimulated extremely rapidly after perception of social opportunity, probably to allow suppressed males to quickly achieve reproductive success in a dynamic social environment.
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Affiliation(s)
- Karen P Maruska
- Stanford University, Department of Biology, 371 Serra Mall, Stanford, California 94305, USA.
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36
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Gharaei A, Mahboudi F, Esmaili-Sari A, Edalat R, Adeli A, Keyvanshokooh S. Molecular cloning of cDNA of mammalian and chicken II gonadotropin-releasing hormones (mGnRHs and cGnRH-II) in the beluga (Huso huso) and the disruptive effect of methylmercury on gene expression. FISH PHYSIOLOGY AND BIOCHEMISTRY 2010; 36:803-817. [PMID: 19821139 DOI: 10.1007/s10695-009-9356-0] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/16/2008] [Accepted: 09/16/2009] [Indexed: 05/28/2023]
Abstract
Two gonadotropin-releasing hormone (GnRH) isoforms were identified in the beluga (Huso huso) brain by cDNA sequencing: prepro-mammalian GnRH (mGnRH) and prepro-chicken GnRH-II (cGnRH-II). The nucleotide sequences of the beluga mGnRH and cGnRH-II precursors are 273 and 258 base pairs (bp) long, encoding peptides of 91 and 86 amino acids, respectively. To investigate the effect of methylmercury (MeHg) on GnRH gene expression, animals were fed with four diets containing increasing levels of MeHg (0 mg kg(-1) [control]; 0.76 mg kg(-1) [low]; 7.8 mg kg(-1) [medium]; 16.22 mg kg(-1) [high]) for 32 days. The effects of MeHg on brain GnRH mRNA levels were evaluated by real-time PCR. A significant decrease in brain mGnRH and cGnRH-II mRNA levels were detected in fish receiving high dietary MeHg dose compared to controls on day 11 (P < 0.05). On day 18 and 32, all treatment groups had significantly lower brain mGnRH and cGnRH-II mRNA levels compared to the control group (P < 0.05). These findings demonstrate a disruptive role of MeHg on the level of brain mGnRH and cGnRH-II mRNAs in immature beluga.
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Affiliation(s)
- Ahmad Gharaei
- Department of Fisheries, Faculty of Natural Resources, Universityof Zabol, P.O.Box 98615-538, Zabol, Sistan & Blouchestan, Iran.
| | | | - Abbas Esmaili-Sari
- Department of Environment, Faculty of Natural Resources and Marine Science, Tarbiat Modares University, Noor, Mazandaran, Iran
| | - Rozita Edalat
- Biotechnology Research Center, Pasteur Institute of Iran, Tehran, Iran
| | - Ahmad Adeli
- Biotechnology Research Center, Pasteur Institute of Iran, Tehran, Iran
| | - Saeed Keyvanshokooh
- Department of Fisheries, Faculty of Marine Natural Resources, Khorramshahr University of Marine Science and Technology, Khorramshahr, Khouzestan, Iran
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37
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Lin CJ, Wu GC, Lee MF, Lau EL, Dufour S, Chang CF. Regulation of two forms of gonadotropin-releasing hormone receptor gene expression in the protandrous black porgy fish, Acanthopagrus schlegeli. Mol Cell Endocrinol 2010; 323:137-46. [PMID: 20398731 DOI: 10.1016/j.mce.2010.04.003] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/23/2009] [Revised: 02/08/2010] [Accepted: 04/01/2010] [Indexed: 10/19/2022]
Abstract
Two GnRH receptors (GnRH-R I and GnRH-R II) were obtained in protandrous black porgy (Acanthopagrus schlegeli). We investigated their tissue distribution, developmental/seasonal changes and regulation of expression using in vivo and in vitro (primary cultures of dispersed pituitary cells) approaches. The relative expressions of GnRH-Rs in the pituitary and gonad were as follows: pituitary: GnRH-R I > GnRH-R II; testicular tissue: GnRH-R I > GnRH-R II; ovarian tissue: GnRH-R I = GnRH-R II. GnRH-R I but not GnRH-R II expression was higher in the pituitary during the spawning period as compared to the prespawning. The expression profiles of both forms of GnRH-R were variable in the gonads according to the gonadal stage and season. In vivo, hCG stimulated GnRH-R I and GnRH-R II expression in testis and ovary. The LHRH analog also up-regulated both receptors in testis and but increased only GnRH-R II in the ovary. Sex steroids (estradiol, E2 and testosterone, T) increased the expression of both receptors in the testis and ovary. In the pituitary, sex steroids (E2 and T) increased the expression of GnRH-R I, but not GnRH-II, both in vivo and in vitro. The LHRH analog also specifically up-regulated the expression of GnRH-R I, but not GnRH-R II, by pituitary cells in vitro. All these data suggest that GnRH-R I rather than GnRH-R II may play a major physiological role in the pituitary. In contrast, both GnRH-R I and GnRH-R II may participate in the regulation of gonadal functions, including a possible role during sex change.
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Affiliation(s)
- Chien-Ju Lin
- Department of Aquaculture, National Taiwan Ocean University, Keelung 20224, Taiwan
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Luckenbach JA, Dickey JT, Swanson P. Regulation of pituitary GnRH receptor and gonadotropin subunits by IGF1 and GnRH in prepubertal male coho salmon. Gen Comp Endocrinol 2010; 167:387-96. [PMID: 19800342 DOI: 10.1016/j.ygcen.2009.09.010] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/12/2009] [Revised: 09/05/2009] [Accepted: 09/25/2009] [Indexed: 02/08/2023]
Abstract
Insulin-like growth factor 1 (IGF1) is a key somatotropic hormone that may convey growth status to the reproductive endocrine system. This study examined effects of IGF1 alone or in combination with gonadotropin-releasing hormone (GnRH) on pituitary transcripts for GnRH receptor (GnRHR) variants, follicle-stimulating hormone (FSH), luteinizing hormone (LH), growth hormone (GH), and IGF, as well as secretion of FSH in vitro. Three experiments were conducted with dispersed pituitary cells of prepubertal male coho salmon (Oncorhynchus kisutch) to determine the time course of the response to IGF1, IGF1 concentration response, and GnRH concentration response. IGF1 consistently elevated pituitary transcripts for gnrhr1 and the four gonadotropin subunits (fshb, lhb, cga1, and cga2) by day 10 of culture, while suppressing gh and igf2. Short-term treatment with GnRH (24h) induced minor increases in transcripts for fshb, cga1, and cga2, but suppressed lhb and strongly inhibited gnrhr1 expression. IGF1 significantly increased GnRH-stimulated FSH protein release by the pituitary cells, although not as robustly as previously observed in more reproductively advanced salmon. Our results demonstrate that IGF1 increases steady-state mRNA levels of gnrhr1 and four gonadotropin subunits, and may act alone or with GnRH to increase pituitary FSH release in male coho salmon, over 1year before puberty. These findings suggest that IGF1 may prime pituitary gonadotrope cells of prepubertal salmon to respond to GnRH by stimulating synthesis of GnRHR and FSH during puberty onset.
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Affiliation(s)
- J Adam Luckenbach
- School of Aquatic and Fishery Sciences, University of Washington, Seattle, WA 98195, USA.
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Zhao Y, Bretz CA, Hawksworth SA, Hirsh J, Johnson EC. Corazonin neurons function in sexually dimorphic circuitry that shape behavioral responses to stress in Drosophila. PLoS One 2010; 5:e9141. [PMID: 20161767 PMCID: PMC2818717 DOI: 10.1371/journal.pone.0009141] [Citation(s) in RCA: 63] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2009] [Accepted: 01/22/2010] [Indexed: 11/19/2022] Open
Abstract
All organisms are confronted with dynamic environmental changes that challenge homeostasis, which is the operational definition of stress. Stress produces adaptive behavioral and physiological responses, which, in the Metazoa, are mediated through the actions of various hormones. Based on its associated phenotypes and its expression profiles, a candidate stress hormone in Drosophila is the corazonin neuropeptide. We evaluated the potential roles of corazonin in mediating stress-related changes in target behaviors and physiologies through genetic alteration of corazonin neuronal excitability. Ablation of corazonin neurons confers resistance to metabolic, osmotic, and oxidative stress, as measured by survival. Silencing and activation of corazonin neurons lead to differential lifespan under stress, and these effects showed a strong dependence on sex. Additionally, altered corazonin neuron physiology leads to fundamental differences in locomotor activity, and these effects were also sex-dependent. The dynamics of altered locomotor behavior accompanying stress was likewise altered in flies with altered corazonin neuronal function. We report that corazonin transcript expression is altered under starvation and osmotic stress, and that triglyceride and dopamine levels are equally impacted in corazonin neuronal alterations and these phenotypes similarly show significant sexual dimorphisms. Notably, these sexual dimorphisms map to corazonin neurons. These results underscore the importance of central peptidergic processing within the context of stress and place corazonin signaling as a critical feature of neuroendocrine events that shape stress responses and may underlie the inherent sexual dimorphic differences in stress responses.
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Affiliation(s)
- Yan Zhao
- Department of Biology, Wake Forest University, Winston-Salem, North Carolina, United States of America
| | - Colin A. Bretz
- Department of Biology, Wake Forest University, Winston-Salem, North Carolina, United States of America
| | - Shane A. Hawksworth
- Department of Biology, Wake Forest University, Winston-Salem, North Carolina, United States of America
| | - Jay Hirsh
- Department of Biology, University of Virginia, Charlottesville, Virginia, United States of America
| | - Erik C. Johnson
- Department of Biology, Wake Forest University, Winston-Salem, North Carolina, United States of America
- * E-mail:
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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: 333] [Impact Index Per Article: 23.8] [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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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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43
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Chang JP, Johnson JD, Sawisky GR, Grey CL, Mitchell G, Booth M, Volk MM, Parks SK, Thompson E, Goss GG, Klausen C, Habibi HR. Signal transduction in multifactorial neuroendocrine control of gonadotropin secretion and synthesis in teleosts-studies on the goldfish model. Gen Comp Endocrinol 2009; 161:42-52. [PMID: 18838074 DOI: 10.1016/j.ygcen.2008.09.005] [Citation(s) in RCA: 75] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/02/2008] [Revised: 08/29/2008] [Accepted: 09/08/2008] [Indexed: 11/25/2022]
Abstract
In teleosts, gonadotropin (GTH) secretion and synthesis is controlled by multiple neuroendocrine factors from the hypothalamus, pituitary and peripheral sources. Pituitary gonadotropes must be able to differentiate and integrate information from these regulators at the cellular and intracellular level. In this article, the intracellular signal transduction mechanisms mediating the actions of some of these regulators, including GTH-releasing hormones, pituitary adenylate cyclase-activating polypeptide, dopamine, ghrelin, sex steroids, activin, and follistatin from experiments with goldfish are reviewed and discussed in relation with recent findings. Information from other teleost models is briefly compared. Goldfish gonadotropes possess multiple pharmacologically distinct intracellular Ca2+ stores that together with voltage-sensitive Ca2+ channels, Na+/H+ exchangers, protein kinase C, arachidonic acid, NO, protein kinase A, ERK/MAPK, and Smads allows for integrated control by different neuroendocrine factors.
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Affiliation(s)
- John P Chang
- Department of Biological Sciences, University of Alberta, CW405 Biological Sciences Building, Edmonton, Alberta, Canada T6G 2E9.
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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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Popesku JT, Martyniuk CJ, Mennigen J, Xiong H, Zhang D, Xia X, Cossins AR, Trudeau VL. The goldfish (Carassius auratus) as a model for neuroendocrine signaling. Mol Cell Endocrinol 2008; 293:43-56. [PMID: 18657592 DOI: 10.1016/j.mce.2008.06.017] [Citation(s) in RCA: 119] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/16/2007] [Revised: 04/30/2008] [Accepted: 06/11/2008] [Indexed: 12/25/2022]
Abstract
Goldfish (Carassius auratus) are excellent model organisms for the neuroendocrine signaling and the regulation of reproduction in vertebrates. Goldfish also serve as useful model organisms in numerous other fields. In contrast to mammals, teleost fish do not have a median eminence; the anterior pituitary is innervated by numerous neuronal cell types and thus, pituitary hormone release is directly regulated. Here we briefly describe the neuroendocrine control of luteinizing hormone. Stimulation by gonadotropin-releasing hormone and a multitude of classical neurotransmitters and neuropeptides is opposed by the potent inhibitory actions of dopamine. The stimulatory actions of gamma-aminobutyric acid and serotonin are also discussed. We will focus on the development of a cDNA microarray composed of carp and goldfish sequences which has allowed us to examine neurotransmitter-regulated gene expression in the neuroendocrine brain and to investigate potential genomic interactions between these key neurotransmitter systems. We observed that isotocin (fish homologue of oxytocin) and activins are regulated by multiple neurotransmitters, which is discussed in light of their roles in reproduction in other species. We have also found that many novel and uncharacterized goldfish expressed sequence tags in the brain are also regulated by neurotransmitters. Their sites of production and whether they play a role in neuroendocrine signaling and control of reproduction remain to be determined. The transcriptomic tools developed to study reproduction could also be used to advance our understanding of neuroendocrine-immune interactions and the relationship between growth and food intake in fish.
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Biran J, Ben-Dor S, Levavi-Sivan B. Molecular identification and functional characterization of the kisspeptin/kisspeptin receptor system in lower vertebrates. Biol Reprod 2008; 79:776-86. [PMID: 18509165 DOI: 10.1095/biolreprod.107.066266] [Citation(s) in RCA: 183] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
The KISS1 gene encodes the kisspeptin neuropeptide, which activates the KISS1 receptor (KISS1R; G protein-coupled receptor 54; GPR54) and participates in neuroendocrine regulation of GnRH secretion. To study the physiological function(s) and evolutionary conservation of KISS1, we cloned opossum, Xenopus, and zebrafish kiss1 cDNAs. Processing zebrafish, Xenopus, or opossum KISS proteins would liberate a carboxy-terminal amidated peptide with 52, 54, or 53 amino acid residues, respectively. Phylogenetic analysis of all known vertebrate KISS1 peptides showed clear clustering of the sequences according to canonical vertebrate classes. The zebrafish kiss1 gene consists of two exons and one intron. Real-time PCR analysis of two kiss1R cloned from zebrafish brain found expression of kiss1, kiss1ra, and kiss1rb, with kiss1ra-more similar to other piscine Kiss1 receptors-highly expressed in the gonads and kiss1rb in other nonbrain tissues. In females kiss1 mRNA levels gradually increased during the first few weeks of life to peak in fish with ovaries containing mature oocytes, while in males kiss1 mRNA levels peaked after 6 wk postfertilization when the testes exhibited initial stages of spermatogenesis and decreased after puberty. Zebrafish kiss1ra and kiss1rb were expressed differentially with similar patterns in both genders. These results indicate that the Kiss1/Kiss1r system may participate in puberty initiation in fish as well. Like human KISS1R, Kiss1ra transduces its activity via the PKC pathway, whereas Kiss1rb does so via both PKC and PKA pathways. The human KISS1R was highly activated by both huKISS10amide and zfKISS10amide, whereas both zebrafish Kiss1 receptor types were less sensitive to amidation.
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Affiliation(s)
- Jakob Biran
- Department of Animal Sciences, The Hebrew University, 76100 Rehovot, Israel
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Nocillado JN, Elizur A. Neuroendocrine regulation of puberty in fish: insights from the grey mullet (Mugil cephalus) model. Mol Reprod Dev 2008; 75:355-61. [PMID: 17721924 DOI: 10.1002/mrd.20744] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
We investigated the molecular regulation of pubertal development in the grey mullet, Mugil cephalus, a relatively late-maturing teleost fish. We have isolated and characterized the cDNAs of key reproductive genes along the brain-pituitary-gonadal (BPG) axis as well as the promoters of genes that modulate the axis at multiple levels. Together with relevant findings from other model species, we propose a conceptual model of the neuroendocrine regulation of puberty in the female grey mullet. Research areas that warrant further investigation are identified in the model.
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Affiliation(s)
- Josephine N Nocillado
- Faculty of Science, Health and Education, University of the Sunshine Coast, Maroochydore DC, Australia
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48
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Martinez-Chavez CC, Minghetti M, Migaud H. GPR54 and rGnRH I gene expression during the onset of puberty in Nile tilapia. Gen Comp Endocrinol 2008; 156:224-33. [PMID: 18329643 DOI: 10.1016/j.ygcen.2008.01.019] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/26/2007] [Revised: 01/28/2008] [Accepted: 01/31/2008] [Indexed: 11/16/2022]
Abstract
The Kiss1/GPR54 system has recently been shown to play a key role in the onset of puberty in mammals. Growing evidence suggests that this system is also conserved across vertebrates although very few studies so far have been performed in lower vertebrates. The aims of this study were firstly in the teleost Nile tilapia to screen tissues for GPR54 expression levels, secondly to measure the expression patterns of GPR54 and GnRH I receptor (rGnRH I) in whole brains during the onset of puberty and finally to determine the effects of continuous illumination (LL) on receptor expression levels. Results confirmed that GPR54 was predominantly expressed in the brain and pituitary of adult tilapia. Furthermore, a significant increase of GPR54 gene expression was found in tilapia brains at 11 weeks post hatch (wph) followed by rGnRH I at 13 wph just prior to the histological observation of vitellogenic oocytes and active spermatogenesis in ova and testes at 17 wph. These results suggest a correlation between the increase of GPR54 expression in the brain and the onset of puberty. Finally, a significant effect of LL was observed on GPR54 expression levels which were characterized by a delayed surge with significantly lower levels than those of control fish. The current study not only suggests a link between the Kiss1/GPR54 system and the onset of puberty in a tropical batch spawning teleost that would be a highly conserved feature across vertebrates but also that the transcriptional mechanisms regulating GPR54 expression could be directly or indirectly influenced by light.
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Avitan A, Zelinger E, Levavi-Sivan B. Homologous desensitization and visualization of the tilapia GnRH type 3 receptor. Gen Comp Endocrinol 2007; 153:182-8. [PMID: 17507014 DOI: 10.1016/j.ygcen.2007.04.003] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/06/2006] [Revised: 03/25/2007] [Accepted: 04/01/2007] [Indexed: 11/21/2022]
Abstract
Two types of gonadotropin-releasing hormone (GnRH) receptors were found in the pituitary of tilapia (t), named GnRHR type 3 (tGnRHR3) and GnRHR type 1, according to phylogenetic analysis. tGnRHR3 is highly expressed in the posterior part of the pituitary which contains LH and FSH cells. We characterized tGnRHR3 in terms of both LH release rate and receptor internalization rate in response to continuous exposure to GnRH. Constant exposure of tilapia pituitary fragments to salmon GnRH analog (sGnRHa) resulted in an increased secretion rate for 3h, followed by a gradual decline, taking 17-19h, to the basal secretion rate. A chimera between tGnRHR3 and green fluorescent protein (GFP) was created and used to observe the changes in receptor distribution and translocation, activated by agonist with time. The results suggested that the receptor is initially localized at the plasma membrane and upon activation by a homologous ligand (e.g. sGnRHa) undergoes relatively rapid endocytosis. In summary, the present work demonstrates that tGnRHR3 has already undergone endocytosis after 30min, while desensitization of LH release occurs only after 17-19h. It is concluded that for tGnRHR3, internalization of the receptor is not exclusively responsible for the desensitization of LH release.
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Affiliation(s)
- Ayelet Avitan
- Department of Animal Sciences, Faculty of Agricultural, Food and Environmental Quality Sciences, The Hebrew University, P.O. Box 12, Rehovot 76100, Israel
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50
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Aizen J, Kasuto H, Levavi-Sivan B. Development of specific enzyme-linked immunosorbent assay for determining LH and FSH levels in tilapia, using recombinant gonadotropins. Gen Comp Endocrinol 2007; 153:323-32. [PMID: 17507016 DOI: 10.1016/j.ygcen.2007.04.004] [Citation(s) in RCA: 75] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/17/2006] [Revised: 03/25/2007] [Accepted: 04/01/2007] [Indexed: 11/21/2022]
Abstract
We recently produced Oreochromis niloticus recombinant LH and FSH as single-chain polypeptides in the methylotrophic yeast Pichia pastoris. Glycoprotein subunit alpha was joined with tilapia (t) LHbeta or tFSHbeta mature protein-coding sequences to form a fusion gene that encodes a ;;tethered" polypeptide, in which the gonadotropin beta-subunit forms the N-terminal part and the alpha-subunit forms the C-terminal part. Recombinant (r) gonadotropins were used to develop specific and homologous competitive ELISAs for measurements of FSH and LH in the plasma and pituitary of tilapia, using primary antibodies against rtLHbeta or rtFSHbeta, respectively, and rtLHbetaalpha or rtFSHbetaalpha for the standard curves. The wells were coated with either rtLHbeta (2ng/ml) or rtFSHbeta (0.5ng/well), and the final concentrations of the antisera were 1:5000 (for tLH) or 1:50,000 (for tFSH). The sensitivity of the assay was 15.84pg/ml for tLH and 0.24pg/ml for tFSH measurements in the plasma, whereas for the measurements in the pituitary, the sensitivity was 2.43ng/ml and 1.52ng/ml for tLH and tFSH, respectively. The standard curves for tFSH and tLH paralleled those of serially diluted pituitary extracts of other cichlids, as well as of serially diluted pituitary extract of seabream, European seabass and hybrid bass. We examined plasma tFSH and tLH levels in the course of one reproductive cycle, between two successive spawnings, in three individual tilapia females. Plasma levels of both FSH and LH increased during the second day after the eggs had been removed, probably related to the vitellogenic phase. LH levels increased toward spawning, which occurred on the 11th day. FSH levels also increased on day of cycle, probably due to recruitment of a new generation of follicles for the successive spawning. The development of specific ELISAs using recombinant gonadotropins is expected to advance the study of the distinct functions of each of these important hormones.
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Affiliation(s)
- Joseph Aizen
- Department of Animal Sciences, Faculty of Agricultural, Food and Environmental Quality Sciences, The Hebrew University, P.O. Box 12, Rehovot 76100, Israel
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