VITELLOGENIN INDUCTION BY XENOBIOTIC ESTROGENS IN THE RED-EARED TURTLE AND AFRICAN CLAWED FROG

Many environmental pollutants have estrogenic activity in animals. Xen obiotic estrogens include many pesticides and industrial chemicals tha t bioaccumulate. The impact of these common pollutants on the reproduc tive success of wildlife may be considerable, particularly in threaten ed or endangered species. This research examined the use of plasma vit ellogenin in males as a biomarker for estrogenic xenobiotics in reptil es and amphibians. Adult male turtles (Trachemys scripta) and frogs (X enopus laevis) were given ip injections of estradiol-17 beta (E(2)), d iethylstilbestrol (DES), or o,p(')-DDT -[2,2,2-trichioro-1-(4-chloroph enyl)ethyl(benzene) daily for 7 days, and plasma was collected on day 14. The estrogenic activity of each compound was determined by measuri ng the induction of plasma vitellogenin. Vitellogenin was identified b y precipitation, electrophoresis, Western blot, and enzyme-linked immu nosorbant assay (ELISA). In both species, estradiol and DES treatments induced the most vitellogenin, whereas DDT treatments induced smaller amounts of viteliogenin in a dose-dependent fashion. These data indic ate that induction of plasma vitellogenin in males may be a useful bio marker of xenobiotic estrogen activity in wild populations of reptiles and amphibians.