Induction of fish vitellogenin and alterations in testicular structure: Preliminary results of estrogenic effects in chub (Leuciscus cephalus)

Laboratory and field studies were carried out in order to assess, in a comm on cyprinid freshwater fish, the chub (Leuciscus cephalus), the feasibility of biological methods to detect and quantify estrogenic effects. In the la boratory the effects of 17beta estradiol were investigated on Vitellogenin (Vtg) induction and on testis organisation. Vtg was quantified by immunodet ection using an established ELISA for carp (Cyprinus carpio) Vtg. Estradiol exposure resulted in a significant and rapid increase in plasma Vtg in bot h male and female chub, indicating that vitellogenic response in the chub i s sensitive to estrogen(s). Histological examination of the testis in males exposed to estradiol also showed effects on the testis. Preliminary field studies on wild chub showed that fish living in a polluted river had elevat ed concentrations of plasma Vtg and had some alterations in the testis comp ared with wild fish from a reference site. Together these preliminary labor atory and field results show that chub could be an interesting fish species for further studies of biological effects of environmental estrogens in th e aquatic environment.