Vitellogenin induction as a function of ovarian cycles and organic pollutants in turtles

This thesis focuses on the process of vitellogenesis; the estrogen induced production of the egg yolk precursor protein in oviparous vertebrates. The cyclical production of vitellogenin is not well understood in turtle species; therefore, the first objective of this thesis was to describe vitellogenin production in reproductively active and quiescent loggerhead sea turtles ( Caretta caretta). Vitellogenin in nesting females decreased as the nesting season progressed, and was significantly greater in nesting females than in in-water capture turtles.;Vitellogenin is considered a reliable biomarker for exposure to estrogenic compounds in oviparous vertebrates since its production can be induced by exogenous estrogen or estrogen-mimicking compounds. The second objective of this thesis was to test the hypotheses that exposure to an estrogenic congener of polychlorinated biphenyl (PCB) induces vitellogenesis in red-eared slider turtles (Trachemys scripta elegans). The results indicate that exposure to relatively high dose of congener PCB 30 induces vitellogenin production.