MULTIGENERATIONAL STUDY OF THE EFFECTS OF CONSUMPTION OF PCB-CONTAMINATED CARP FROM SAGINAW BAY, LAKE-HURON, ON MINK - 2 - LIVER PCB CONCENTRATION AND INDUCTION OF HEPATIC CYTOCHROME-P-450 ACTIVITY AS A POTENTIAL BIOMARKER FOR PCB EXPOSURE

This study examined the effect of polychlorinated biphenyls (PCBs) fro m Saginaw Bay (Lake Huron) carp on the hepatic cytochrome P-450 activi ty in mink (Mustela vison). Hepatic cytochrome P-450 activities are of interest for their possible use as biomarkers to indicate consumption and biological effects of PCBs in the environment. Adult mink were le d diets containing ocean fish (control diet, 0.0 ppm) or Saginaw Bay c arp to provide 0.25, 0.5, or 1.0 ppm PCBs. Mink were bred after 3 mo o f exposure, and half of the parental mink (P-1) and kits (F-1-l) previ ously consuming diets containing Saginaw Bay carp were switched to con trol diet at weaning of the F-1-1 kits. P-1 and F-1-1 mink were then b red within their age and dietary groups after /5 mo of exposure, to pr oduce the second-year F-1 (F-1-2). and F-2 kits. Mink were killed when the new kits were weaned. Transfer of half the animals to the control diet examined whether the effects of the PCB-containing diet on hepat ic cytochrome P-450 activity were permanent. Continual exposure to die ts containing PCBs from Saginaw Bay carp induced cytothrome P-450 acti vity in a generally dose-dependent manner. Cytochrome P-450 activity w as no different from untreated controls in animals switched to the con trol diet from the PCB-containing diet. The response of cytochrome P-4 501A1 (EROD) activity in a dose-dependent manner and the lack of induc tion after transfer to noncontaminated diets suggest that this hepatic enzyme activity is a potential biomarker for current exposure to PCBs and other similar cytochrome P-450 inducers.