Bisphenol A Exposure, Ovarian Follicle Numbers, and Female Sex Steroid Hormone Levels: Results from a CLARITY-BPA Study.
Endocrinology. 2017 Mar 16. Epub 2017 Mar 16. PMID: 28324068
Bisphenol A (BPA) is an industrial chemical found in thermal receipts, and food and beverage containers. Previous studies have shown that BPA can affect the numbers and health of ovarian follicles and the production of sex steroid hormones, but they often did not include a wide-range of doses of BPA, used a small sample size, focused on relatively short-term exposures to BPA, and/or did not examine the consequences of chronic BPA exposure on the ovaries or steroid levels. Thus, this study was designed to examine the effects of a wide range of doses of BPA on ovarian morphology and sex steroid hormone production. Specifically, this study tested the hypothesis that prenatal and continuous BPA exposure reduces ovarian follicle numbers and sex steroid hormone levels. To test this hypothesis, rats were dosed with vehicle, ethinyl estradiol (0.05 and 0.5μg/kg bw/day), or BPA (2.5, 25, 250, 2,500, and 25,000 μg/kg bw/day) from gestation day 6 until 1 year as part of the Consortium Linking Academic and Regulatory Insights on BPA Toxicity (CLARITY-BPA). Ovaries and sera were collected on postnatal days 1, 21, 90, 6 months, and 1 year. The ovaries were subjected to histological evaluation of follicle numbers and the sera subjected to measurements of estradiol and progesterone. Collectively, these data indicate that BPA exposure at some doses and time-points affects ovarian follicle numbers and sex steroid levels, but these effects are differentthan those observed with ethinyl estradiol exposure and some previous studies on BPA.