Effects of perinatal octylphenol on ultrasound vocalization, behavior and reproductive physiology in rats.

A rodent diet containing paraffin wax was designed to administer the environmental estrogen octylphenol (OP) to nonpregnant, pregnant and lactating rats. The estrogenic activity of OP via this diet was first confirmed in ovariectomized adult animals: 20 mg OP/kg/day increased the mitoses in the vaginal epithelium, and 60 mg OP/kg/day stimulated mitoses in the uterine luminal epithelium. The effects on a variety of reproductive and nonreproductive parameters were then investigated in the offspring of dams fed OP (100-250 mg/kg/day during gestation and lactation). A number of modest reproductive and morphological effects observed in the offspring including decreased body weights in adults of both sexes, disrupted vaginal cyclicity and decreases in seminiferous tubule diameter and testis, kidney, spleen and ovary weights. Behavioral effects included increased sexual arousal in males, increased sexual motivation in females towards a female teaser and increased motor activity by females. Ultrasonic vocalizations by pups at Postnatal Day (PND) 7 were reduced in number and duration in both sexes. There were no effects of perinatal OP on ano-genital distance, prepuce separation, aggressive behavior or adult ultrasound vocalization. These observations confirm that the dietary intake of estrogenic amounts of OP during pregnancy and lactation can have a wide variety of effects in the offspring.