Fetal bisphenol A and ethinylestradiol exposure alters male rat urogenital tract morphology at birth: Confirmation of prior low-dose findings in CLARITY-BPA.

Bisphenol A (BPA) is a contaminant in virtually all Americans. To examine BPA's adverse effects, the FDA-NCTR, NIEHS, and 14 groups of academic scientists formed a consortium: CLARITY-BPA. The purpose of our study was to investigate the effects of a wide range of doses of BPA on fetal development of the NCTR CD-SD male rat urogenital sinus (UGS). Pregnant rats were administered BPA or positive control ethinylestradiol (EE2) daily, via oral gavage, from gestational day 6 through parturition. Tissues were collected on postnatal day 1 and the UGS was analyzed using computer-assisted 3-D reconstruction. Importantly, only low doses of BPA, as well as EE2, significantly changed birth weight and UGS morphology, including an increased size of the colliculus and decreased size of the urethra, consistent with prior reported BPA and EE2 effects. Our findings provide further evidence that BPA mediates nonmonotonic developmental effects on the fetal urogenital sinus.