Meeting Abstract

P2-111  Tuesday, Jan. 5 15:30  Effects of estrogen and atrazine on the histology and function of the thymus gland of Xenopus laevis REILLY, C; DEPOY, E*; MORRA, A; CAPRIOTTI, D; MONHART, M; MORANTE, K; FATEYE, B/A; SCHREIBER, A/M; Biology Department, St Lawrence University; Biology Department, St Lawrence University; Biology Department, St Lawrence University; Biology Department, St Lawrence University; Biology Department, St Lawrence University; Biology Department, St Lawrence University; Biology Department, St Lawrence University; Biology Department, St Lawrence University bfateye@stlawu.edu

Introduction of estrogens and estrogen-like pollutants into the natural habitats of aquatic species has been shown to adversely influence the physiology and ecology of these species. For example, we have shown that exposure of tadpoles to estradiol (10uM) induces apoptosis and involution of the thymus gland of Xenopus laevis. Since the thymus plays an important in the development of larval and adult immune cells in vertebrates, we compared the susceptibility to injections of live yeast (Saccharomyces cerevisiae) among X. laevis at different stages of natural metamorphosis or in tadpoles exposed for 1-5 weeks to estradiol, atrazine or dexamethasone. Premetamorphic tadpoles [Nieuwkoop-Faber (NF) stage 50] and post climax froglets were more susceptible to yeast injections compared with other stages of metamorphosis. Using immunohistochemistry, we detail the spatiotemporal changes in thymus structure and composition after exposure to the chemicals.