Strain comparisons of atrazine-induced pregnancy loss in the rat.
Atrazine was administered by gavage, in 1% methylcellulose, to F344 Sprague-Dawley (SD), and Long Evans (LE) rats at 0, 25, 50, 100, or 200 mg/kg/day on gestation days 6 through 10. The dams were allowed to deliver and litters were examined postnatally. The F344 strain was the most sensitive to atrazine's effects on pregnancy, showing full-litter resorption (FLR) at >/=50 mg/kg. In surviving F344 litters, prenatal loss was increased at 200 mg/kg. In SD and LE rats, FLR occurred only at 200 mg/kg. Delayed parturition was seen at >/=100 mg/kg in F344 and SD rats. Regarding maternal toxicity, the SD dams were the most sensitive, with weight loss at >/=25 mg/kg. When 200 mg/kg was administered to F344 rats on days 11 through 15 (after the LH-dependent period of pregnancy), no FLR was seen. These findings suggest that atrazine-induced FLR is maternally mediated, and consistent with loss of LH support of the corpora lutea.
Narotsky
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MG
Reproductive Toxicology Division, National Health and Environmental Effects Research Laboratory, US Environmental Protection Agency, 27711, Research Triangle Park, NC, USA. narotsky.michael@epa.gov
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D000818:Animals; D001280:Atrazine / Q000633:toxicity*; D005260:Female; D005327:Fetal Resorption / Q000139:chemically induced*; D006540:Herbicides / Q000633:toxicity*; D007986:Luteinizing Hormone / Q000502:physiology; D008297:Male; D011247:Pregnancy; D051381:Rats; D011916:Rats, Inbred F344; D020318:Rats, Long-Evans; D017207:Rats, Sprague-Dawley; D013045:Species Specificity
D006540:Herbicides; D007986:Luteinizing Hormone; D001280:Atrazine