IMMUNOQUANTITATION OF CYTOCHROMES P450 1A AND P450 2B AND COMPARISON WITH CHLORINATED-HYDROCARBON LEVELS IN ARCHIVED POLAR BEAR LIVER SAMPLES

The present study examined the utility of an immunoblot method for qua ntitation of cytochrome P450 isozymes in archived liver samples as a b ioassay of exposure to halogenated hydrocarbons. Hepatic microsomes we re prepared from 44 archived polar bear (Ursus maritimus) liver homoge nates that had been stored at approximately -40 degrees C for 9-10 yea rs and analyzed on blots probed with antibodies to rat cytochromes P45 0 1A1 and P450 2B1. The results revealed a positive correlation betwee n cytochrome P450 1A and total polychlorinated biphenyl (PCB) levels i n the archived liver samples, suggesting that cytochrome P450 1A was i nduced in polar bears by environmental exposure to PCBs. (C) 1997 Else vier Science Ltd.