Embryonic treatment with xenobiotics disrupts steroid hormone profiles in hatchling red-eared slider turtles (Trachemys scripta elegans)

Many compounds in the environment capable of acting as endocrine disruptors have been assayed for their developmental effects on morphogenesis; howeve r, few studies have addressed how such xenobiotics affect physiology. In th e current study we examine the effects of three endocrine-disrupting compou nds, chlordane, trans-nonachlor, and the polychlorinated biphenyl (PCB) mix ture Aroclor 1242, on the steroid hormone concentrations of red-eared slide r turtle (Trachemys scripta elegans) hatchlings treated in ovo. Basal stero id concentrations and steroid concentrations in response to follicle-stimul ating hormone were examined in both male and female turtles treated with ea ch of the three compounds. Treated male turtles exposed to Aroclor 1242 or chlordane exhibited significantly lower testosterone concentrations than co ntrols, whereas chlordane-treated females had significantly lower progester one, testosterone, and 5 alpha-dihydrotestosterone concentrations relative to controls. The effects of these endocrine disruptors extend beyond embryo nic development, altering sex-steroid physiology in exposed animals.