Meeting Abstract

P2.140  Wednesday, Jan. 5  Interference of estradiol metabolism during embryonic development: a mechanism of action for Bisphenol-A CLAIRARDIN, SG*; PAITZ, RT; BOWDEN, RM; Illinois St. Univ.; Illinois St. Univ.; Illinois St. Univ. sgclair@ilstu.edu

Endocrine disrupting compounds (EDCs) have been implicated in a variety of biological problems from population decline to various cancers. Bisphenol-A (BPA) is one such endocrine disruptor that is widely used in manufacturing and is nearly ubiquitous in the environment. BPA has been shown to have estrogenic (feminizing) effects in developing organisms from a wide range of vertebrate taxa; however, little is known about the mechanism by which this chemical exerts its effects. One possible mechanism is through disruption of steroid metabolism. In the red-eared slider turtle (Trachemys scripta), estradiol (E2) levels in the yolk decline rapidly during the first 10 days of development as E2 is conjugated primarily to estradiol sulfate (E2-S). We hypothesized that the estrogenic effects of BPA are due to inhibition of E2 metabolism and predicted that BPA would inhibit the decline of E2 levels in the yolk. To test this, T. scripta eggs were treated on day zero (day of oviposition) with 0.1 µg E2 in combination with 0, 392, or 785 µg BPA (approximately 0, 35, or 70 ppm, respectively). Following exposure, eggs were sampled every 3 days of development for 9 days. E2 levels in yolk samples were measured using radioimmunoassay and results demonstrate that BPA significantly affected the levels of E2 in the yolk, suggesting inhibition of steroid metabolism. We will also measure E2-S to test inhibition of steroid metabolism as a mechanism for this effect. These data will provide insight into how BPA, and potentially other EDCs, produce their estrogenic effects.