Meeting Abstract

9.5  Wednesday, Jan. 4  Can environmental contaminants alter sex hormone signaling of splenic function in the American alligator? KOHNO, S*; STERN, WH; LOWERS, RH; GUILLETTE, LJ; Univ. Florida, Dept. Biology and Med. Univ. South Carolina, Dept. Ob/Gyn; Univ. Florida, Dept. Biology and College Medicine; Kennedy Space Center, Innovative Health Applications; Univ. Florida, Dept. Biology and Med. Univ. South Carolina, Dept. Ob/Gyn kohno@musc.edu

The American alligator is a sentinel species for local environmental contaminations because of its habitat, feeding hierarchy and non-migration. Some contaminants have the potential to disrupt the immune and endocrine system in wildlife as well as in humans. Indeed, American alligators in Lake Apopka, contaminated with agricultural chemicals exhibit altered immune and reproductive function. Interactions between sex hormones and immune system function have been demonstrated in mammals, but have not been examined in alligators. The aim of this study is to help clarify potential environmental impacts on the interaction between immune system function and sex steroid hormones. The spleen of juvenile female American alligators from Lake Apopka (AP) were compared with those from a reference site (WO) and from coastal Merritt Island (MI) National Wildlife Refuge. Splenic mass index was smaller at MI compared to WO and AP. Density of the periarterial lymphoid sheath in spleen, indicating immune active level, was higher in AP and MI than WO, although an area of red pulp in spleen, indicating immune function and red blood cells turnover, did not showed differences among the sites. Estrogen receptor 1 (ESR1) and androgen receptor (AR) mRNAs were expressed in alligator spleen. Spleens from AP alligators expressed higher ESR1 mRNA than tissues from WO, whereas no difference was noted in AR mRNA expression. These results suggest direct interactions of estrogen and androgen with the spleen, a central organ of immune function. Although MI alligators exhibited altered characteristics in splenic mass and histology, the causal factors could be different than those observed at AP.