NORMAL SEXUAL DEVELOPMENT OF RATS EXPOSED TO BUTYL BENZYL PHTHALATE FROM CONCEPTION TO WEANING

Butyl benzyl phthalate (BBP) has been administered in drinking water ( 1000 mu g/liter) to pregnant AP rats during gestation and lactation. T he sexual development of the pups was then monitored until their termi nation at postnatal day 90 (pnd 90). Pups derived from animals exposed to diethylstilbestrol (DES) in drinking water (50 mu g/liter) acted a s a positive control group. Glass drinking bottles were employed follo wing demonstration of absorption of BBP into plastic drinking bottles. Drinking water intake was monitored and the estimated average exposur es of the dams was 182.6 mu g/kg/day BBP and 8.6 mu g/kg/day DES. A to tal of 240 control pups, 204 BBP pups, and 64 DES pups were obtained f or study. The sexual development of both genders of pups was monitored . The body weights of the DES pups were significantly reduced at birth , an effect that persisted until pnd 90. The body weights of the BBP p ups were marginally increased at birth, but this difference resolved b y pnd 90. DES affected the sexual development of the pups for all endp oints monitored-anogenital (AG) distance on pnd 2; average day of vagi nal opening and prepuce separation; uterus, testes, and accessory sex gland weight; and cauda epididymis sperm count and homogenization resi stant testicular sperm count at pnd 90. BBP failed to affect any of th ese parameters, with the exception of a 1.1-day advance in the average day of vaginal opening and a small increase in male AG; distance on p nd 2. These last two effects are related to the increased weight of th e BBP pups. The incidence of FSH-containing cells in the pituitary gla nd of animals from each group was unaffected at pnd 90. The effects ob served for the DES pups are consistent with the results of earlier stu dies by Sharpe et al. (Environ. Health Perspect. 103, 1136-1143, 1995) . However, the absence of an effect of BBP administration on pup testi s weight and testicular sperm count at pnd 90 is in contrast to reduct ions in these measurements reported earlier by Sharpe ef al. (Environ. Health Perspect. 103, 1136-1143, 1995) for similarly derived BBP pups . (C) 1997 Academic Press.