Event Abstract Back to Event Testosterone rapidly increases milt output in male goldfish (Carassius auratus) Lisa A. Mangiamele1* and Richmond R. Thompson1 1 Bowdoin College, Department of Psychology, Program in Neuroscience, United States In many vertebrates, interactions between males and females stimulate rapid increases in the steroid hormones testosterone (T) and estradiol (E2). Recent work has demonstrated that both T and E2 act to rapidly (< 1 hr) facilitate male sexual behaviors (Remage-Healey and Bass, 2006; Lord et al., 2009). However, whether and how steroids may also rapidly influence reproductive physiology and/or mating success has been less well studied. To address this issue, we investigated rapid T effects on milt (sperm and seminal fluid) production in goldfish. We isolated mature male goldfish in small groups for 2 days. On the third day we selected a focal male from each tank and measured the volume of milt expressed. We then injected males I.P. with either 3 μg T in saline + 0.1% methanol or an equivalent volume of saline vehicle. After 1 hr we measured milt volume and took blood samples from all fish. Compared to pre-injection milt volumes, males injected with T rapidly increased their milt output by 54%. In contrast, saline-treated males decreased milt volume by 44%. We then tested whether T elicited rapid increases in milt via its conversion to E2 by aromatase. To do this, we isolated males in small groups for 2 days. On the third day we injected focal males with either Fadrozole (an aromatase inhibitor) or saline, and 30 min later we measured milt volume and injected each group with 3 μg T. A third group of males received two saline injections. We measured milt volume at 1 hr post-T injection and found that Fadrozole blocked the T-induced increase in milt production. Together, these results suggest that T, via activation of estrogen receptors in the brain or periphery, can significantly increase sperm output over the short time scales that characterize reproductive encounters. Because goldfish spawn in groups in which males engage in intense competition for access to females, such T-induced increases in milt output may enhance a male’s ability to engage in sperm competition and, therefore, influence his reproductive success. Acknowledgements This work was supported by Bowdoin College and NSF IOS 0849102 to R.R.T. References Lord, L.D., Bond, J., and Thompson, R.R. (2009). Rapid steroid influences on visually-guided sexual behavior in male goldfish. Horm. Behav. 56: 519-526. Remage-Healey, L. and Bass, A.H. (2006). A rapid neuromodulatory role for steroid hormones in the control of reproductive behavior. Brain Res. 1126: 27-35. Keywords: Aromatase, Carassius auratus, estrogen receptor, rapid steroid effects, sperm, Testosterone 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: Neuroendocrine control of reproduction Citation: Mangiamele LA and Thompson RR (2011). Testosterone rapidly increases milt output in male goldfish (Carassius auratus). Front. Endocrinol. Conference Abstract: NASCE 2011: The inaugural meeting of the North American Society for Comparative Endocrinology. doi: 10.3389/conf.fendo.2011.04.00093 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: 22 Jul 2011; Published Online: 09 Aug 2011. * Correspondence: Dr. Lisa A Mangiamele, Bowdoin College, Department of Psychology, Program in Neuroscience, Brunswick, Maine, 04011, United States, lmangiam@bowdoin.edu 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 Lisa A Mangiamele Richmond R Thompson Google Lisa A Mangiamele Richmond R Thompson Google Scholar Lisa A Mangiamele Richmond R Thompson PubMed Lisa A Mangiamele Richmond R Thompson 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.