Regulation of ovarian prostaglandin synthesis in the zebrafish: actions of 17α, 20β-dihydroxy-4-pregnen-3-one and insulin-like growth factor-1

Abstract

Event Abstract Back to Event Regulation of ovarian prostaglandin synthesis in the zebrafish: actions of 17α, 20β-dihydroxy-4-pregnen-3-one and insulin-like growth factor-1 Nicholas C. Melnyk1, Andrea L. Lister1 and Glen J. Van Der Kraak1* 1 University of Guelph, Canada Oocyte maturation and ovulation are sequential events leading to the release of an oocyte that is ready to be fertilized. While earlier studies have shown that 17α, 20β-dihydroxy-4-pregnen-3-one (17,20β-P) and the insulin-like growth factor (IGF) system are regulators of oocyte maturation in the zebrafish (Danio rerio), it is not known whether these hormones play a role in the regulation of prostaglandin synthesis which is thought to mediate ovulation. The goal of this study was to determine in mid-vitellogenic (MV) and full grown (FG) zebrafish ovarian follicles whether 17,20β-P and human recombinant IGF-1 affect the expression of genes involved in prostaglandin biosynthesis including phospholipase A2 (cpla2), cycoloxygenase -1 (ptgs1) and cyclooxygenase 2 (ptgs2), or the levels of prostaglandin E2 (PGE2) and prostaglandin F2α (PGF2α). Both 17,20β-P and IGF-1 stimulated oocyte maturation in both size classes of follicles. In FG follicles, addition of 17,20β-P caused an increase in cpla2 expression, whereas IGF-1 increased ptgs2 expression and at high concentrations stimulated cpla2. There was an additive increase in cpla2 expression when both hormones were combined. Measurement of prostaglandin levels from the incubation medium revealed that both 17,20β-P and IGF-1 increased PGF2α production, and IGF-1 also induced PGE2 synthesis. Interestingly, 17,20β-P had no effect on cpla2 and ptgs2 expression and PGF2α production in MV follicles, whereas IGF-1 stimulated the expression of both cpla2 and ptgs2 and production of PGF2α in these follicles. Collectively, these results suggest that the regulation of prostaglandin biosynthesis in fish ovarian follicles may involve the coordinated actions of 17,20β-P and IGFs. Furthermore there are developmental differences in the responsiveness of MV and FG follicles to these regulators. Acknowledgements This work was supported by an NSERC Discovery Grant to Glen Van Der Kraak. Keywords: cyclooxygenase, Insulin-like growth factor, Maturation inducing steroid, Oocyte maturation, phospholipase, prostaglandin Conference: NASCE 2011: The inaugural meeting of the North American Society for Comparative Endocrinology, Ann Arbor, United States, 13 Jul - 16 Jul, 2011. Presentation Type: Poster Topic: Gonadal development and gamete maturation Citation: Melnyk NC, Lister AL and Van Der Kraak GJ (2011). Regulation of ovarian prostaglandin synthesis in the zebrafish: actions of 17α, 20β-dihydroxy-4-pregnen-3-one and insulin-like growth factor-1. Front. Endocrinol. Conference Abstract: NASCE 2011: The inaugural meeting of the North American Society for Comparative Endocrinology. doi: 10.3389/conf.fendo.2011.04.00037 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: 12 Jul 2011; Published Online: 09 Aug 2011. * Correspondence: Dr. Glen J Van Der Kraak, University of Guelph, Guelph, Canada, gvanderk@uoguelph.ca 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 Nicholas C Melnyk Andrea L Lister Glen J Van Der Kraak Google Nicholas C Melnyk Andrea L Lister Glen J Van Der Kraak Google Scholar Nicholas C Melnyk Andrea L Lister Glen J Van Der Kraak PubMed Nicholas C Melnyk Andrea L Lister Glen J Van Der Kraak 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.