The effects of prenatal exposure to atrazine on pubertal and postnatal reproductive indices in the female rat.

Atrazine (ATR) is an herbicide that exerts negative reproductive effects. We examined the effects of vehicle or ATR (1, 5, 20 and 100mg/kg-d), administered to Sprague-Dawley rats on gestational days 14-21, once daily or divided into two doses per day, on female offspring reproductive indices. Offspring body weights at birth were reduced and mortality increased in the 100mg/kg-d group shortly after birth; by PND 21 there were no significant effects. Vaginal opening was delayed in this group, indicating delayed puberty. No significant differences in mammary gland development were apparent at PND 45, or estrous cyclicity through PND 272. There were no differences between dosing regimens. Lower ATR doses (0-20mg/kg-d) showed few effects in females prenatally exposed to ATR, while the high dose (100mg/kg-d) reduced offspring body weight and delayed vaginal opening. Nonetheless, it is unlikely that environmental exposure comparable to the high dose would be encountered.