Effect of in vitro xenoestrogens on steroidogenesis in mature female fish, Chasmichthys dolichognathus

In this study, fully vitellogenic oocytes of the longchin goby (Chasmichthys dolichognathus) were exposed to in vitro xenoestrogens such as diethylstilbestrol ( DES), bisphenol A (BPA) and nonylphenol (NP) at concentrations of 100 ng/ml in the presence of [H-3]17alpha-hydroxyprogesterone as precursor. The major metabolites produced in vitro are progestogens [17alpha-hydroxy, 20alpha-dihydroprogesterone (17alpha20alphaOHP) and 17alpha-hydroxy, 20beta-dihydroprogesterone (17alpha20betaOHP)], androgens [androstenedione (A4) and testosterone (T)] and estrogens [estrone (E1) and estradiol-17beta (E2)]. Comparative activities of these chemicals in oocyte steroid biosynthesis showed as follows: NP treatment resulted in clear stimulation of estrogen production, while the opposite occurred in DES treated incubation. Treatment with DES resulted in a higher synthesis of 17alpha20alphaOHP. BPA treatment increased the androgen, while estrogen synthesis was slightly inhibited. These results suggest that NP exhibited clearly estrogenic activity on the three chemicals.