Meeting Abstract

132.5  Tuesday, Jan. 7 14:30  In-vitro Assessment of the Potential Effects of Environmental Contaminants on California Condor (Gymnogyps californianus) Reproductive Health GERRARD, R*; TUBBS, C; San Diego Zoo Institute for Conservation Research; San Diego Zoo Institute for Conservation Research rgerrard@mail.missouri.edu

The recovery of the critically endangered California condor (CAC; Gymnogyps californianus) has required significant human intervention and management. Inland CAC populations face challenges associated with lead poisoning, which pushed this species to the brink of extinction in 1987. Coastal CACs scavenge marine megafauna that offer reduced lead exposure, but increased potential exposure to organochlorides. Although whether organochlorides contributed to the CAC’s original population decline is controversial, recent evidence of exposure to organochlorides, such as DDTs, PCBs, and chloradanes, exists. Specifically, eggshells of coastal birds have recently been found to be significantly thinner than inland birds, providing a possible linkage between environmental chemical exposure to impaired reproductive health. To investigate the effects of organochlorides on CAC reproduction we have cloned CAC estrogen receptors 1 and 2 (ESR1 and ESR2) and characterized their activation by pertinent organochlorides. Treatment of HEK293 cells expressing CAC ESR1 with 10^-12-10^-4M p,p’ DDE, PCB153 or trans-nonachlor resulted in weak to moderate receptor activation. In comparison, ESR2, which has not been identified in any bird of prey, showed overall greater sensitivity to these compounds with trans-nonachlor being the most potent agonist followed by PCB153 and p,p’DDE. Our findings suggest that CAC reproductive health may be affected by persistent organochlorides in coastal environments. However, additional studies are needed to elucidate the extent of CAC exposure to these endocrine-disrupting contaminants to better inform the management of this critically endangered species.