Effects of atrazine on sexual maturation in female Japanese quail induced by photostimulation or exogenous gonadotropin.

The herbicide atrazine has gained recent attention for its reported effects on reproduction in amphibians. The present study examined the putative effects of atrazine during sexual maturation in the photostimulated female Japanese quail. Furthermore, the effects of atrazine on birds administered exogenous gonadotropin (pregnant mare serum gonadotropin [PMSG]) were investigated. Atrazine was administered up to 1,000 ppm in the diet to female quail undergoing photoperiodically induced sexual maturation. At high dietary concentrations, atrazine exhibits signs of overt toxicity with reductions in growth, feed intake, and liver weights, but these effects were dependent on the timing of treatment administration. Atrazine did not influence the weights of reproductive tissues (ovary and oviduct) or circulating concentrations of luteinizing hormone (LH). However, high concentrations of atrazine depressed circulating concentrations of estradiol. Treatment with atrazine for four weeks during sexual maturation inhibited growth but did not affect any other parameter assessed (feed intake, liver, ovary, or oviduct weights or the circulating concentrations of LH and estradiol). In birds receiving daily injections of PMSG, atrazine reduced growth, feed intake, and liver weights. However, PMSG-induced gonadal and oviduct growth was not affected by atrazine. The present results suggest that dietary atrazine exhibits limited reproductive toxicity in female quail during sexual maturation and only at concentrations above ecological relevance.