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 center dot kg(-1)center dot day(-1) 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 center dot kg(-1)center dot day(-1) 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 center dot kg(-1)center dot day(-1) 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 center dot kg(-1)center dot day(-1) dose of BPA might advance pubertal development significantly. In addition, within the range of 0 to 10 mg center dot kg(-1)center dot day(-1), neonatal exposure to BPA may affect pubertal development in a dose-dependent manner.