Development and implementation of endocrine biomarkers of exposure and effects in American alligators (Alligator Mississippiensis)

This study reports on the developmental effects of potential xenobiotic substances that may alter endocrine physiology during embryogenesis in the American alligator (Alligator naississippiensis). Eggs collected from a wild population were treated with either 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), o,p′-DDE, p,p′-DDE, ethynylestradiol, coumestrol, or indole-3-carbinol at several dose levels. Treated eggs were incubated at temperatures that normally produce all male hatchlings (33°C). Several biochemical and morphological endpoints were evaluated from hatchling alligators at three weeks of age. Sex determination contrary to that expected by incubation temperature was exhibited by those embyos treated with ethynylestradiol, p,p′-DDE (higher doses), and TCDD (higher doses). Control alligator embryos resulted in predominately male phenotypes. Vitellogenin induction was not apparent in xenobiotic-treated alligator hatchlings, and this may be a reflection of the fact that these animals possessed substantial abdominal yolk reserves.