PH25 Wildlife Ecotoxicology II
Exhibit Hall
8:00 AM - Thursday
(PH295) Androgen active contaminants disrupt development of the bursa of Fabricius: a possible mechanism of immunosuppression in birds?
Quinn, Jr., M1, Lavoie, E1, Abdelnabi, M1, Ottinger, M1, 1 University of Maryland, College Park, MD, USA
ABSTRACT- Many mechanisms behind endocrine disrupting chemical (EDC)-induced immunosuppression remain unclear. Research has focused on EDCs that affect the estrogen and thyroid systems, leaving the androgen system, which is most often considered immunosuppressive, virtually untouched. By determining causes of impaired immunocompetence by androgenic and anti-androgenic chemical exposure, this study will help elucidate some of the mechanisms behind EDC-induced immunosuppression. We hypothesized that immunosuppression in birds that is caused by exposure to androgenic or anti-androgenic chemicals immunosuppression occurs mainly through disruption of the development of the bursa of Fabricius, an avian immune organ responsible for B cell maturation. Trenbolone acetate, a synthetic androgen, was injected into the yolk of Japanese quail (Coturnix japonica) eggs on day 4 of incubation at 0.5, 5, 50, or 125 
g, and DDE, and anti-androgen, was injected on day 1 of incubation at 20.0 or 40.0 g. A sesame oil vehicle control was included. Spleens and bursas were collected and weighed at day of hatch and adulthood, and histological measurements were made. Spleens from both chicks and adults appeared to be unaffected by either chemical. Bursas from chicks treated with DDE were larger than, had fewer follicles (site of B cell maturation), had loss of plicae, and exhibited vacuolization within follicles compared to controls. Bursas from chicks treated with trenbolone were smaller, had fewer follicles, had loss of plicae, and exhibited thicker epithelial layers between plicae conpared to controls. Bursas from adults that were embronically exposed to either chemical did not differ from controls. DDE and trenbolone acetate disrupted bursal development, however, it appears that Japanese quail bursas recover from early developmental abberations caused by these chemicals. Partially funded by Battelle Labs in support of a U.S. EPA contract.
Key words: trenbolone acetate, DDE, bursa, immunosuppression