title: A novel neuropeptide in suppressing luteinizing hormone release in goldfish, Carassius auratus.
abstract: The fish reproductive axis is regulated by many neuroendocrine factors. However, factors involved in the suppression of this axis are largely uncharacterized. In this study, we describe a novel neuropeptide derived from the spexin precursor acting as a negative factor to suppress the reproductive axis in teleost. The cDNA sequences of the spexin precursors have been cloned from both zebrafish and goldfish. A 14-aa mature peptide with the C-terminal amidated (spexin-14a: NWTPQAMLYLKGTQ-NH2) is conceivably generated by processing of the spexin precursors in both species. Spexin is mainly expressed in the brain and ovary of zebrafish and spexin-14a-ir cells are located in several brain regions of goldfish. Functionally, goldfish spexin-14a could significantly suppress luteinizing hormone (LH) release in cultured goldfish pituitary cells. Moreover, intraperitoneal injection of spexin-14a could effectively suppress serum LH level. The mRNA expression of spexin is lower in the breeding season and hypothalamic expression of spexin is regulated by gonadal hormones. These results constitute the first report on the novel role of spexin in the negative regulation of the reproductive axis in teleost.
authors.affiliation: State Key Laboratory of Biocontrol, Institute of Aquatic Economic Animals, and the Guangdong Province Key Laboratory for Aquatic Economic Animals, Sun Yat-Sen University, Guangzhou 510275, China.
authors.forename: Yun
authors.initials: Y
authors.lastname: Liu
authors.forename: Shuisheng
authors.initials: S
authors.lastname: Li
authors.forename: Xing
authors.initials: X
authors.lastname: Qi
authors.forename: Wenyi
authors.initials: W
authors.lastname: Zhou
authors.forename: Xiaochun
authors.initials: X
authors.lastname: Liu
authors.forename: Haoran
authors.initials: H
authors.lastname: Lin
authors.forename: Yong
authors.initials: Y
authors.lastname: Zhang
authors.forename: Christopher H K
authors.initials: CH
authors.lastname: Cheng
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D005260:Female; D005786:Gene Expression Regulation; D006054:Goldfish / Q000235:genetics* / Q000378:metabolism; D007987:Gonadotropin-Releasing Hormone / Q000235:genetics / Q000378:metabolism; D007031:Hypothalamus / Q000378:metabolism; D007986:Luteinizing Hormone / Q000235:genetics* / Q000378:metabolism; D008297:Male; D008969:Molecular Sequence Data; D009479:Neuropeptides / Q000235:genetics* / Q000378:metabolism; D010053:Ovary / Q000378:metabolism; D010902:Pituitary Gland / Q000166:cytology / Q000378:metabolism*; D012098:Reproduction / Q000235:genetics*; D015398:Signal Transduction; D015027:Zebrafish / Q000235:genetics / Q000378:metabolism
chemical_list: D009479:Neuropeptides; D007987:Gonadotropin-Releasing Hormone; D007986:Luteinizing Hormone