[Disturbances of prenatal development in rats exposed to fenitrothion]

Female rats were given fenitrothion by gavage every other day from days 6-15 of gestation at daily doses 3, 15, 30, 45 mg/kg (0.3%, 1.7%, 3.4%, 5.2% LD50). Assessment of general toxicity of pregnant dams (death rate, body weight gain, food and water consumption, relative and absolute organs weight, hematocrit and hemoglobin level), embryotoxicity, fetotoxicity and teratogenicity of fenitrothion was performed. Death rate in female rats exposed at doses 45 mg/kg and 30 mg/kg was 88% and 39% respectively. The toxic activity of fenitrothion at dose 30 mg/kg was reflected in significant decreased body weight gain, food consumption, also hemoglobin and hematocrit values and decreased of absolute weight of liver and kidneys, increased relative weight of adrenal and ovaries. The toxic activity at dose 15 mg/kg/day was reflected in significant decreased of relative weight of liver. At the dose 30 mg/kg of fenitrothion exhibited embryotoxic effect producing significant increase in the frequency of early resorption per litter and postimplantation losses. Fetotoxic effect manifested by increased of frequency fetuses and litters with enlarged cerebral ventricles was observed at doses 15 mg/kg and 30 mg/kg. Furthermore, at dose 30 mg/kg fenitrothion produced delayed ossification of sternum and cranium, and decrease fetal body weight and length. Fenitrothion at doses 3-30 mg/kg did not induced teratogenic effects. The NOAEL for developmental toxicity was 3 mg/kg/day (0.3 LD50) and the LOAEL 15 mg/kg/day (1.7 LD50).