Hormonal action of a relaxin-like gonad-stimulating substance (GSS) in starfish, Asterina pectinifera

Abstract

Event Abstract Back to Event Hormonal action of a relaxin-like gonad-stimulating substance (GSS) in starfish, Asterina pectinifera Masatsohi Mita1*, Kazutoshi Yamamoto2 and Yoshitaka Nagahama3 1 Tokyo Gakugei University, Department of Biology, Japan 2 Waseda University, Department of Biology, Japan 3 National Institute for Basic Biology, Laboratory of Reproductive Biology, Japan Gonad-stimulating substance (GSS) of starfish is the only known invertebrate peptide hormone responsible for final gamete maturation, rendering it functionally analogous to gonadotropins in the vertebrates. GSS stimulates ovary to induce oocyte maturation by producing maturation-inducing hormone, 1-methyladenine (1-MeAde) in the ovarian follicle cells. Recently, we purified GSS of starfish, Asterina pectinifera, from radial nerves and identified the chemical structure as a heterodimer composed of two different peptides (A- and B-chain) with disulfide cross-linkages. According to phylogenetic analyses, starfish GSS belongs to the insulin/insulin-like growth factor (IGF)/relaxin superfamily and, more precisely, to the subclass of a relaxin-like peptide. In this study, we examined de novo synthesis and hormonal actions of GSS. The cDNA of GSS encoded a preprohormone sequence with a C-peptide between the A- and B-chains. High levels of mRNA expression and activity of GSS were detected in the radial nerves and nerve rings. Further, the chemically synthesized GSS could stimulate ovarian follicle cells to produce 1-MeAde through an increase in cyclic AMP. According to competitive experiments using radioiodinated and radioinert GSS, highly specific bindings were observed in the membrane fraction of follicle cells, suggesting that GSS receptors are distributed on the follicle cell membrane. Additionally, alpha subunit of stimulatory type of G-protein was immunologically detected in the membrane fraction. These findings strongly suggest that upon secretion from nervous tissues, GSS interacts with its receptor on the follicle cell surface to activate G-proteins and adenylyl cyclase and induce 1-MeAde production. Keywords: comparative endocrinology Conference: 25th Conference of the European Comparative Endocrinologists, Pécs, Hungary, 31 Aug - 4 Sep, 2010. Presentation Type: Conference Presentation Topic: Comparative endocrinology Citation: Mita M, Yamamoto K and Nagahama Y (2010). Hormonal action of a relaxin-like gonad-stimulating substance (GSS) in starfish, Asterina pectinifera. Front. Endocrinol. Conference Abstract: 25th Conference of the European Comparative Endocrinologists. doi: 10.3389/conf.fendo.2010.01.00010 Copyright: The abstracts in this collection have not been subject to any Frontiers peer review or checks, and are not endorsed by Frontiers. They are made available through the Frontiers publishing platform as a service to conference organizers and presenters. The copyright in the individual abstracts is owned by the author of each abstract or his/her employer unless otherwise stated. Each abstract, as well as the collection of abstracts, are published under a Creative Commons CC-BY 4.0 (attribution) licence (https://creativecommons.org/licenses/by/4.0/) and may thus be reproduced, translated, adapted and be the subject of derivative works provided the authors and Frontiers are attributed. For Frontiers’ terms and conditions please see https://www.frontiersin.org/legal/terms-and-conditions. Received: 26 Aug 2010; Published Online: 29 Aug 2010. * Correspondence: Dr. Masatsohi Mita, Tokyo Gakugei University, Department of Biology, Tokyo, Japan, bio-mita@u-gakugei.ac.jp Login Required This action requires you to be registered with Frontiers and logged in. To register or login click here. Abstract Info Abstract The Authors in Frontiers Masatsohi Mita Kazutoshi Yamamoto Yoshitaka Nagahama Google Masatsohi Mita Kazutoshi Yamamoto Yoshitaka Nagahama Google Scholar Masatsohi Mita Kazutoshi Yamamoto Yoshitaka Nagahama PubMed Masatsohi Mita Kazutoshi Yamamoto Yoshitaka Nagahama Related Article in Frontiers Google Scholar PubMed Abstract Close Back to top Javascript is disabled. Please enable Javascript in your browser settings in order to see all the content on this page.