Neonatal exposure to bisphenol A advances pubertal development in female rats.

Neonatal exposure to bisphenol A (BPA) is hypothesized to advance pubertal development. However, the effects of neonatal BPA exposure on pubertal development has not been described. In this study, female Sprague-Dawley rats were exposed to 0.05, 0.5, 5, or 10 mg·kg ·day BPA, or corn oil vehicle alone from postnatal day 1 (PND1) to PND10 via subcutaneous injection. We evaluated day of vaginal opening (DVO), ovarian morphology, serum hormone concentrations, and hypothalamic expression of Gnrh1 and Kiss1 in female rats at PND35. DVO was significantly advanced in rats exposed to 5 and 10 mg·kg ·day BPA. Serum hormone concentrations increased as BPA dose increased. Additionally, hypothalamic Gnrh1 and Kiss1 expression were increased with BPA exposure; rats exposed to 10 mg·kg ·day BPA had significantly upregulated hypothalamic Gnrh1 and Kiss1 expressions in terms of both messenger RNA and protein levels. Our results suggest that exposure to a 10 mg·kg ·day dose of BPA might advance pubertal development significantly. In addition, within the range of 0 to 10 mg·kg ·day , neonatal exposure to BPA may affect pubertal development in a dose-dependent manner.