High doses of atrazine do not disrupt activity and expression of aromatase in female gonads of juvenile goldfish (Carassius auratus L.).

Juveniles female goldfish were exposed to atrazine (2-chloro-4-ethylamino-6-isopropylamino-s-triazine) at high doses, 100 and 1000 microg l(-1) during 56 days in order to evaluate the potential action of the herbicide as an endocrine disruptor. Plasma concentration of estradiol (E2) and 11-ketotestosterone (11-KT) as well as activity and expression of aromatase in the gonads were evaluated. These parameters were completed with morphological measures such as gonadosomatic index (GSI) and histological analyses of gonads. Morphological parameters at both 100 and 1000 microg l(-1) did not show any significant differences with the control groups. Correlated to the pathway hypothesized, no time-, dose-related effects were detected on the aromatase activity and the expression in the gonads of juvenile female goldfish. The same conclusion was attributed regarding the circulating E2 where no perceptible variation was detected. Nevertheless, a hormonal imbalance was detected for plasma concentration of the sex steroid 11-KT of fish exposed to 1000 microg l(-1) after 56 days exposure. In these particular experimental conditions, we failed to demonstrate an effect of atrazine through the induction of aromatase and hormonal imbalance associated.