Meeting Abstract

P1.121  Monday, Jan. 4  Are estrogenic effects of bisphenol A due to inhibition of estrogen metabolism? CLAIRARDIN, SG*; PAITZ, RT; BOWDEN, RM; Illinois St. Univ.; Illinois St. Univ.; Illinois St. Univ. sgclair@ilstu.edu

Bisphenol A (BPA) is a man made chemical that can disrupt endocrine signaling and is of particular public concern due to its wide use in the production of consumer products. Although some of the estrogenic effects of BPA have been described, little is known about the mechanism by which this chemical exerts its effects. One possible mechanism is through disruption of steroid metabolism. We hypothesized that the estrogenic effects of BPA are due to inhibition of estrogen (E2) metabolism. In the red-eared slider (Trachemys scripta), E2 levels in the yolk decline rapidly during the first 15 days of development. We predicted that BPA would inhibit this decline, leading to estrogenic effects such as the increased production of female hatchlings. To test this, ten clutches of eggs were divided as follows: two eggs were sampled at oviposition, two eggs were treated with vehicle only (ethanol) and the remaining eggs were treated with 0.1 µg of E2 in ethanol plus one of three doses of BPA (0, 1.0, or 10.0 µg). Eggs were then incubated at 27°C; on incubation days 2 and 12, one egg from each E2 treatment was sampled. Vehicle and any additional E2 treated eggs in the larger clutches were incubated to hatch. E2 was quantified in the yolks of eggs sampled on Day 0, 2, and 12. E2 administration did significantly elevate E2 levels in the day 2 eggs compared to the untreated day 0 eggs. By day 12, E2 had declined to similar levels in all groups. To determine the effects of BPA treatment on hatchling phenotype we will measure hatchling mass, plastron length, righting time, and sex. These parameters, along with information about steroid levels, will aid our understanding about the effects of BPA, as well as potential mechanisms through which it may exert its effects.