Developmental toxicity of the substituted phenylurea herbicide isoproturon in rats.

Isoproturon, a substituted phenylurea herbicide, was studied for its toxicity to dams and its potential fetotoxic/teratogenic effects in the fetuses of albino rats. Isoproturon technical administered orally at 45, 90 or 180 mg/kg/d to dams during d 6-20 of pregnancy did not produce maternal toxicity at 45 or 90 mg/kg/d. However, 180 mg isoproturon/kg/d caused changes in maternal enzymes and chromatid breaks. There was no fetotoxic/teratogenic effect of isoproturon at the tested dosage levels in number of implantations, percent resorption, fetal weights, and external, visceral and skeletal fetal observations.