Meeting Abstract

95.3  Saturday, Jan. 7  Endocrine disrupting compound metabolism and the effects of bisphenol-a during development in the red-eared slider turtle (Trachemys scripta) CLAIRARDIN, S. G.*; PAITZ, R. T.; BOWDEN, R. M.; Il. St. Univ.; Il. St. Univ.; Il. St. Univ. sgclair@ilstu.edu

Bisphenol-A (BPA), an endocrine disrupting compound (EDC), can have a wide range of effects including sex reversal, which are often linked to inappropriate estrogen signaling. However, the mechanisms of action for BPA have yet to be fully characterized. One pathway that may be altered is estradiol (E₂) metabolism, as BPA and E₂ are metabolized by the same conjugative enzymes. We have previously shown that BPA can inhibit metabolism of maternal E₂ during early development in Trachemys scripta eggs, which may lead to estrogenic effects. Interactions between timing of exposure and of E₂ metabolism could play a role in defining how EDCs impact development. The present study aimed to understand effects of dose and timing on the outcomes of BPA exposure and whether EDC metabolism may play a role. To test effects of dose and timing on sex, eggs were treated with 0, 3.5 or 35ppm BPA on day 0 (within 24 hrs of laying) or day 21 (beginning of sex-determining period). Eggs were incubated in a fluctuating temperature regime (28° +/- 4C) until hatch. Sex will be determined and ratios compared among groups. To test effects of dose on survival, eggs were treated on day 0 with one of 10 doses (ranging from 0-70ppm BPA), and eggs incubated at 27&degC until hatch to quantify hatching success; sex will be determined and compared among groups. To understand how BPA may elicit its effects, we asked how BPA is metabolized and moved around the egg after exposure. Eggs were exposed to ³H-BPA on day 0 and sampled every 5 days throughout development to identify and quantify metabolites. Connections between EDC metabolism/movement and end-point effects will inform our understanding of overall toxicity, and will provide a mechanistic understanding to aid in interpretation and prediction of context-dependent effects.