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Effects of prenatal exposure to a low dose atrazine metabolite mixture onpubertal timing and prostate development of male Long-Evans rats
Citation:
Stanko, J. P., C. J. WOLF, J. Rayner, AND S. E. Fenton. Effects of prenatal exposure to a low dose atrazine metabolite mixture onpubertal timing and prostate development of male Long-Evans rats. REPRODUCTIVE TOXICOLOGY. Elsevier Science Ltd, New York, NY, 30:540-549, (2010).
Impact/Purpose:
This study assesses strain differences in MG development in LE and SD female offspring prenatally exposed to ATR.
Description:
Atrazine (ATR) is a chlorotriazine herbicide extensively used in the US and other countries. Studies examining the effects of adult or developmental ATR exposure on the mammary gland (MG) have used either the Sprague Dawley (SD) or Long-Evans (LE) rat, but no strain comparisons have been made using identical exposure paradigms. This study assesses strain differences in MG development in LE and SD female offspring prenatally exposed to ATR. Timed-pregnant LE and SD rats (n=5/dose) were gavaged with 0, 12.5,25, or 50 mg ATR/kg body weight 2x/day on gestational days 15-19. Necropsy was conducted on postnatal days (PND) 4, 25, 33, and 45, and vaginal opening (VO) was evaluated in all animals surviving past PND25. Mammary gland development was significantly delayed at PND4 and PND25 in SD rats in the 50 mg ATR group (p<0.05) and at PND33 in both strains in all ATR exposure groups (p<0.05) compared to controls. Though no effects on VO were observed in LE offspring, VO was delayed in SD offspring of the 25 and 50 mg ATR groups (p<0.01) compared to controls. At PND45, MG development was again significantly delayed at all doses in both strains (p<0.0 1). Comparison of MGs across strains at corresponding time and dose points showed a decreased rate of MG development in LE offspring compared to SD. These data indicate prenatal exposure to ATR delays MG development in offspring of both LE and SD and that these effects persist until at least PND45.