Event Abstract Back to Event GHRELIN REGULATES REPRODUCTIVE PHYSIOLOGY IN FISH Erin Shepperd1* and Suraj Unniappan1 1 York University, Biology, Canada Ghrelin, the only known orexigenic gut hormone has been proposed to integrate energy balance and reproduction. There is a large set of data available on the orexigenic and LH stimulatory roles of ghrelin in fish. However, the direct roles of ghrelin on fish gonads remain unclear. Our objective was to characterize the reproductive functions, especially the direct effects of ghrelin on oocyte maturation. We found ghrelin receptor expression in the ovaries and testes of goldfish and zebrafish. Ghrelin receptor mRNA expression in the ovary and testes was relatively lower during the sexually mature stages of goldfish. Further, incubation with native ghrelin at 10ng/mL, 50ng/mL and 100ng/mL concentrations inhibited zebrafish follicle maturation. Oocyte maturation assays also showed that ghrelin inhibited maturation inducing hormone triggered oocyte development. Ghrelin’s role within oocyte maturation is further supported by IHC studies that indicate that ghrelin is localized to the theca and granulosa cell layers that surround the oocyte. Overall, our results indicate that the endogenous ghrelin system in the gonads changes during reproductive stages in goldfish. Ghrelin has an inhibitory role on zebrafish oocyte maturation in vitro and is localized in the cell layers that surround the oocyte. Collectively, our results for the first time indicate a direct role for ghrelin in the ovarian physiology of fish. Acknowledgements This research was funded by the Natural Sciences and Engineering Research Council (NSERC) of Canada through a Discovery Grant, and two Research Tools and Instruments Grants to SU. SU is a Canadian Institutes of Health Research (CIHR) New Investigator and is a recipient of the Early Researcher Award from the Ontario Ministry of Research and Innovation. References Kohli, Clelland & Peng. (2005). Potential targets of transforming growth factor-betaI during inhibition of oocyte maturation in zebrafish. Reproductive Biology and Endocrinology 2005; 3:53. Sokolowska-Mikolajcyzk, Socha, Szczerbok & Epler. (2009). The effects of ghrelin on the in vitro spontaneous and sGnRH-A stimulated luteinizing hormone (LH) release from the pituitary cells of common carp (Cyprinus carpio L.). Comparative Biochemistry and Physiology, Part A 153(2009); 385-390. Amole & Unniappan. (2008). Fasting induces preproghrelin mRNA expression in the brain and gut of zebrafish, Danio rerio. General and Comparative Endocrinology 161 (2009); 133-137. Unniappan. (2010). Ghrelin: An emerging player in the regulation of reproduction in non-mammalian vertebrates. General and Comparative Endocrinology 167 (2010); 340-343. Grey, Grayfer, Belosevic & Chang. (2010). Ghrelin stimulation of gonadotropin (LH) release from goldfish pituitary cells: Presence of the growth hormone secretagogue receptor (GHS-R1a) and involvement of voltage-sensitive Ca2+ channels. Molecular and Cellular Endocrinology 317 (2010); 64-77. Lessman. (2009). Oocyte maturation: Converting the zebrafish oocyte to the fertilizable egg. General and Comparative Endocrinology 161 (2009); 53-57. Unniappan & Peter. (2005). Structure,distribution and physiological functions of ghrelin in fish. Comparative Biochemistry and Physiology, Part A 140 (2005); 396-408. Keywords: Ghrelin, GHS-R, Goldfish, Immunohistochemistry, maturation, oocyte, Ovary, Zebrafish 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: Oral Presentation Topic: Gonadal development and gamete maturation Citation: Shepperd E and Unniappan S (2011). GHRELIN REGULATES REPRODUCTIVE PHYSIOLOGY IN FISH. Front. Endocrinol. Conference Abstract: NASCE 2011: The inaugural meeting of the North American Society for Comparative Endocrinology. doi: 10.3389/conf.fendo.2011.04.00067 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: 18 Jul 2011; Published Online: 09 Aug 2011. * Correspondence: Miss. Erin Shepperd, York University, Biology, Toronto, Ontario, M3J 1P3, Canada, sheppeev@yorku.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 Erin Shepperd Suraj Unniappan Google Erin Shepperd Suraj Unniappan Google Scholar Erin Shepperd Suraj Unniappan PubMed Erin Shepperd Suraj Unniappan 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.