title: Evidences for the regulation of GnRH and GTH expression by GnIH in the goldfish, Carassius auratus.
abstract: Gonadotrophin-inhibitory hormone (GnIH) plays an important role in regulating of reproduction in teleosts. To clarify the mode of action of GnIH on the synthesis of gonadotropin releasing hormone (GnRH) and gonadotrophin (GtH), three GnIHR cDNAs were cloned from the goldfish brain. In situ hybridization results showed that GnIHRs were localized to the hypothalamus and pituitary. In the hypothalamus, GnIHRs were found in the NPP, NPO and NLT, whereas sGnRH neurons were reported to be located, and potentially regulated by GnIH. In the pituitary, only two GnIHRs were observed and they were localized to the PI instead of the adenohypophysis where GtH-expressing cells are localized, suggesting indirect regulation of GtH by GnIH. In vivo, intraperitoneal (i.p.) injections of synthetic goldfish GnIH-II peptide and GnIH-III peptide significantly decreased sGnRH and FSHβ mRNA levels. Only GnIH-II decreased LHβ mRNA levels significantly. In vitro, both GnIH-II and GnIH-III showed no effect on GtH synthesis, but an inhibition of GnRH-stimulated LHβ and FSHβ synthesis was observed when GnIH-III was applied to primary pituitary cells in culture. Thus, GnIH could contribute to the regulation of gonadotropin in the brain and pituitary in teleosts.
authors.affiliation: State Key Laboratory of Biocontrol, Institute of Aquatic Economic Animals, The Guangdong Province Key Laboratory for Aquatic Economic Animals, Sun Yat-Sen University, Guangzhou 510275, China.
authors.forename: Xin
authors.initials: X
authors.lastname: Qi
authors.forename: Wenyi
authors.initials: W
authors.lastname: Zhou
authors.forename: Shuisheng
authors.initials: S
authors.lastname: Li
authors.forename: Danqi
authors.initials: D
authors.lastname: Lu
authors.forename: Shibai
authors.initials: S
authors.lastname: Yi
authors.forename: Rui
authors.initials: R
authors.lastname: Xie
authors.forename: Xiaochun
authors.initials: X
authors.lastname: Liu
authors.forename: Yong
authors.initials: Y
authors.lastname: Zhang
authors.forename: Haoran
authors.initials: H
authors.lastname: Lin
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D003001:Cloning, Molecular; D018076:DNA, Complementary / Q000235:genetics; D005260:Female; D037201:Follicle Stimulating Hormone, beta Subunit / Q000235:genetics / Q000378:metabolism; D005786:Gene Expression Regulation / Q000187:drug effects*; D006023:Glycoproteins / Q000737:chemistry / Q000494:pharmacology*; D006054:Goldfish / Q000235:genetics*; D007987:Gonadotropin-Releasing Hormone / Q000235:genetics* / Q000378:metabolism; D006062:Gonadotropins / Q000235:genetics* / Q000378:metabolism; D007031:Hypothalamus / Q000166:cytology / Q000187:drug effects / Q000378:metabolism; D017403:In Situ Hybridization; D037101:Luteinizing Hormone, beta Subunit / Q000235:genetics / Q000378:metabolism; D008969:Molecular Sequence Data; D010802:Phylogeny; D010902:Pituitary Gland / Q000166:cytology / Q000187:drug effects / Q000378:metabolism; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D011956:Receptors, Cell Surface / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D016415:Sequence Alignment; D017422:Sequence Analysis, DNA
chemical_list: D018076:DNA, Complementary; D037201:Follicle Stimulating Hormone, beta Subunit; D006023:Glycoproteins; D006062:Gonadotropins; D037101:Luteinizing Hormone, beta Subunit; D012333:RNA, Messenger; D011956:Receptors, Cell Surface; C014995:gonadotropin inhibitor; D007987:Gonadotropin-Releasing Hormone