Intersex and liver alterations induced by long-term sublethal 25 exposure to 17α-ethinylestradiol in adult male Cnesterodon decemmaculatus (Pisces, Poeciliidae).
Young, B., López, G. C., Crespo, D., Cristos, D., Somoza, G.M. and Carriquiriborde, P.
Laboratory of Experimental Immunology, Department of International Health, Immunology and Microbiology, Faculty of Health and Medical Sciences, University of Copenhagen, 2200 N Copenhagen, Denmark;
Instituto de Investigaciones Biotecnológicas, Universidad Nacional de San Martín, San Martín, B 1650 HMP, Buenos Aires, Argentina; and.
Instituto de Investigaciones Biotecnológicas, Universidad Nacional de San Martín, San Martín, B 1650 HMP, Buenos Aires, Argentina; and Center for Biological Sequence Analysis, Technical University of Denmark, 2800 Kongens Lyngby, Denmark.
Laboratory of Experimental Immunology, Department of International Health, Immunology and Microbiology, Faculty of Health and Medical Sciences, University of Copenhagen, 2200 N Copenhagen, Denmark; sbuus@sund.ku.dk.
The aim of this study was to assess the response of the gonopodium morphology, and the gonadal and liver histology of adult male Cnesterodon decemmaculatus, to sublethal long-term exposure concentrations of α-ethinylestradiol (EE2). Two experiments were conducted exposing the fish to waterborne concentrations of EE2 ranging from 20 to 200 ng/L for 8, 12 and 16 weeks. Intersex gonads were observed after 8 and 16 weeks in fish exposed to 200 and 100 ng EE2/L, respectively. Oocytes development from testis germ cells, and replacement of the efferent duct PAS positive secretion surrounding spermatozeugmata by parenchymal tissue and duct structure alterations, were the major observed changes in the gonads. On the other hand, no response was observed in the gonopodium morphology. Liver histology was also altered, showing increasing steatosis, single-cell necrosis to generalized necrosis and disruption of acinar organization from 100 to 200 ng EE2/L. In summary, the present results showed that although EE2 was not able to alter the morphology of a developed gonopodium, it was capable of inducing development of testicular oocytes in adult male C. decemmaculatus at environmentally relevant concentrations. Thus, externally normal, but intersex C. decemmaculatus males would be expected in wastewater-receiving streams where the species inhabits. According to the literature, this would be the first report indicating estrogen-induced intersex in adult male poeciilids.
Environmental Toxicology and Chemistry 36(7): 1738-1745 (2017)