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

Endocrine Toxicology Branch, Toxicity Assessment Division, National Health and Environmental Effects Research Laboratory, Office of Research and Development, US Environmental Protection Agency, Research Triangle Park, NC 27711, USA.
Reproductive Toxicology (Impact Factor: 3.23). 04/2011; 32(1):43-51. DOI: 10.1016/j.reprotox.2011.04.004
Source: PubMed


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.

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    • "The no observed effect level (NOEL) based upon sexual maturation delay observed in this study was greater in F 1 progeny administered ATZ only PW (NOEL = 25 mg/kg) compared to animals exposed to ATZ during gestation, lactation , and PW (NOEL = 6.5 mg/kg/day). However, these NOELs were similar to those reported by other investigators who evaluated the effects of ATZ on sexual maturation when administered either during gestation, lactation, and PW (NOEL = 20 mg/kg/day) (Davis et al., 2011) or only PW (NOEL = 10–12.5 mg/kg/day) (Laws et al., 2000; Ashby et al., 2002). "
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    • "Delay in sexual maturation is known to affect mammary gland development because growth during puberty is allometric and sensitive to hormonal changes during the estrous cycle (Hovey et al., 2002). The results from a second laboratory confirmed the absence of an atrazine effect on postnatal mammary gland development at doses as high as 100 mg/kg/day (Davis et al., 2011). In addition, female SD rats exposed to atrazine in utero and throughout life did not have an increased incidence of mammary tumors compared with controls, suggesting that in utero exposure to atrazine did not contribute to an increased risk of developing mammary tumors later in life (Stevens et al., 1999). "
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