Comparison of cytochrome P450 1A induction in blood and liver cells of sea otters

Sea otters in oiled areas of western PWS had elevated levels of cytochrome P450 1A (CYP1A), a biomarker of hydrocarbon exposure, measured in blood samples collected from otters in 1996- 98. In summer 2001, as part of project 01423, we have proposed to resample CYP1A in blood from sea otters in oiled and unoiled areas of PWS. Herein we describe a complementary effort to project 01423. We propose also to sample liver from the captured sea otters, for assays of CYP1A, and for examination of histopathological changes. Liver CYP1A levels will be compared to those measured in blood from the same individuals. We will also assay for CYP1A in archived frozen liver samples from sea otters that were oiled and died in 1989, to enable comparison of current levels of CYP1A induction with levels in sea otters that had a known high degree of oil exposure. The results of this study will provide a basis for comparison of cytochrome P4501A induction in sea otters in 1989, in 1996-98, and in 2001, and will help determine if there is a decline in CYP1A levels over time.