INVESTIGADORES
SOMOZA Gustavo Manuel
congresos y reuniones científicas
Título:
Effects of 17α-ethynylestradiol on the testicular structure of two neotropical fish species.
Autor/es:
GUSTAVO M. SOMOZA; MARIA RITA PÉREZ; BRIAN YOUNG; CARLOS A. STRÜSSMANN
Lugar:
Santos
Reunión:
Congreso; 12th SETAC Latin America Biennial Meeting; 2017
Institución organizadora:
SETAC
Resumen:
The effects of estrogenic compounds in surface waters originated from human activities can affect not only human health but also aquatic wildlife through different mechanisms such as sex inversion, induction of intersex individuals, prevention of gonadal maturation and alterations in sexual behavior. In addition, relatively high concentrations some estrogenic compounds like estradiol (E2) and 17α-ethynylestradiol (EE2), have been reported in surface waters of Brazil and Argentina. Therefore, the objective of this work was to evaluate the effects of environmentally relevant concentrations of EE2 on differentiated testicles of two native species, Cnesterodon decemmaculatus (Cyprinodontiformes), and Odontesthes bonariensis (Atheriniformes), with a similar distribution in Argentina, Uruguay and the South of Brazil. In the case of C. decenmaculatus, adult males were exposed to concentrations of EE2 ranging from 20 to 200 ng/L during 8, 12 and 16 weeks and intersex gonads (testis-ova) were observed after 8 and 16 weeks of fish exposed to fish exposed to 200 ng EE2/L and 100 ng EE2/L, respectively, with no alterations in the morphology of the gonopodium. In the case of O. bonariensis, juvenile male pejerrey were exposed to 15 ng EE2/L for 20 days using a static exposition system. Gene expression of 11β-hydroxysteroid dehydrogenase type 2 (hsd11b2), the enzyme involved in testicular differentiation, was significantly down regulated. On the other hand, the expression of gonadal aromatase (cyp19a1a), the enzyme involved in ovarian differentiation, was significantly up regulated in testes of exposed fish. The histological analysis of the testes showed that, in the treated group, the caudal portion of the gonad exhibited typical characteristics of the ovarian differentiation process of pejerrey larvae. Even though sex inversion or intersex occurrence has not been reported yet in pejerrey, it is likely that the caudal portion remains susceptible to the action of xenoestrogens in sexually immature pejerrey and could impair the reproductive capacity of those individuals. In summary, the present results showed that EE2 exposure effects vary according to the species and the life stage at environmentally relevant concentrations of different local fish species. Then it would be feasible that presence of estrogens in south American surface waters would able to disrupt sexual development or impair the reproductive capacity of fish populations in different ways.