Impact of atrazine on endocrine function in fish

The triazinic herbicide atrazine (2-chloro-4-ethylamino-6-isopylamino-1,3,5-triazine), commonly used in agricultural practices, more specifically in corn fields, is often among the substances detected in surface waters.
Recent studies have shown an influence of this molecule on the hypothalamus-hypophysis axis, leading to the idea that atrazine may act as an endocrine disruptor in mammals ; in rats, the hypothesis has received experimental proofs.
The aim of the present study is to evaluate the impact of atrazine on endocrine function in fish, using goldfish Carassius auratus as a model. Acute and chronic contaminations will be performed in the laboratory, using varying doses of the substance, to meet the following objectives :

-assess the impact of the substance on various organs such as the liver and the gonads, in adults and juveniles ; enzymatic activities of the first (EROD) and second (glutathion S-transferase) phases will serve as indicators;
-identify the possible alterations of the histological organisation and cytological integrity in target organs as a function of the dosis applied (light and electron microscopy);
-evaluate the role played by atrazine on endocrine regulation (sex steroïds and gonadotropins) and the expression of vitellogenin in adult males and juveniles, as well as the disturbances observable in adult females;
-characterize the possible induction of aromatase, a key enzyme in the metabolism of steroïd hormones, and identify the associated receptor(s);
-examine, both in vitro and ex vivo, the impact of the herbicide on hepato- and oocytes. The results obtained will be compared with those collected following in vivo contaminations.