Effects of atrazine on sex steroid dynamics, plasma vitellogenin concentration and gonad development in adult goldfish (Carassius auratus).

Sexually mature goldfish (Carassius auratus) of both sexes were exposed to two doses (100 and 1000 microg/l) of the widely used herbicide atrazine (2-chloro-4-ethylamino-6-isopropylamino-s-triazine) for a period of 21 days and effects on the concentrations of gonad and plasma sex steroids (testosterone (T), 17beta-estradiol (E2) and 11-ketotestosterone (11-KT)), plasma vitellogenin (VTG) and gonad histo-morphology assessed. Atrazine did not show any obvious estrogenic effect in males, as determined by a lack of vitellogenin induction. There were, however, effects of atrazine on plasma androgen concentrations (androgen dynamics) and tissue (plasma and gonad) estrogen concentrations in male goldfish; exposure to 1000 microg/l atrazine induced suppression in both testosterone and 11-ketotestosterone, and resulted in elevated 17beta-estradiol, after 21 day of exposure. Further, these suppressive effects on plasma androgens and the induction in estrogen were dose- and time-related. The highest atrazine exposure dose induced structural disruption in the testis and both 100 and 1000 microg/l induced elevated levels of atresia in ovaries.