The effect of ethynilestradiol on gonopodium morphology and gonadal histology of Cnesterodon decemmaculatus (Pisces, Poeciliidae).

BRIAN YOUNG; GABRIELA C. LÓPEZ; DIANA CRESPO; GUSTAVO M. SOMOZA; PEDRO CARRIQUIRIBORDE

Boston

Congreso; 32nd Annual Meeting of SETAC North America.; 2011

SETA North America

Public and scientic concern about EDCs has claimed for the understanding the mechanism underlying adverse effects and the development of ecotoxicological tools for assessing potential environmental impacts. Ethynilestradiol (EE2) is the main estrogenic component of the combined oral contraceptive pills, and its presence in surface waters has been reported worldwide. Holarctic Poeciliid sh has demonstrated to be valuable indicators of exposure to endocrine-modulating substances, because they exhibit a hormone-dependent sexual dimorphism. In the present study, alterations at the morphology of the gonopodium and the gonadal histology of the Neotropical Poeciliid, Cnesterodon decemmaculatus, in response to the EE2 were assessed under laboratory conditions. Two experiments were conducted exposing adult sh to environmentally and pharmacologically relevant waterborne concentration of EE2, ranging from 25 to 250 ng/L during a 90 days period. e description of the normal morphology of the gonopodium helped to build a gonopodial index for characterizing developmental stages in the studied species. Nevertheless, gonopodium morphology was not sensitive to environmental EE2 exposure, showing no response after 84 d of exposure. However, testicular histology showed primary oocytes in the outer sector since day 54 in sh exposed to 250 ng EE2/L., thee number of oocytes increased and started to invade the central zone of the testis by day 84. Moreover a parenchymatization of the seminal tube lumen was also observed. e study demonstrated the induction of ovotestis (“intersex”) by EE2 in C. decemmaculatus, encouraging the utilization of this local sh as test species for evaluating the impact of EDCs.