Developmental toxicity evaluation of mono-n-butyl phthalate in rats.

Mono-n-butyl phthalate (MBuP) was evaluated for developmental toxicity in Wistar rats. Rats were given MBuP by gastric intubation at 0, 250, 500 or 625 mg/kg on days 7-15 of pregnancy. Significant decreases in the maternal body weight gains and food consumption during pregnancy were found at 500 and 625 mg/kg. Significant increase in the incidence of postimplantation loss per litter and decreases in the number of live fetuses per litter and fetal weight were also detected at 500 mg/kg and above. The incidence of fetuses with malformations in the 500 and 625 mg/kg groups was higher than that in the control group. Cleft palate, deformity of the vertebral column and dilatation of the renal pelvis were frequently observed.