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) from Saginaw Bay (Lake Huron) carp on the hepatic cytochrome P-450 activity 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 fed diets containing ocean fish (control diet, 0.0 ppm) or Saginaw Bay carp to provide 0.25, 0.5, or 1.0 ppm PCBs. Mink were bred after 3 mo of exposure, and half of the parental mink (P1) and kits (F1-1) previously consuming diets containing Saginaw Bay carp were switched to control diet at weaning of the F1-1 kits. P1 and F1-1 mink were then bred within their age and dietary groups after 15 mo of exposure, to produce the second-year F1(F1-2) and F2 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 hepatic cytochrome P-450 activity were permanent. Continual exposure to diets containing PCBs from Saginaw Bay carp induced cytochrome P-450 activity in a generally dose-dependent manner. Cytochrome P-450 activity was not different from untreated controls in animals switched to the control diet from the PCB-containing diet. The response of cytochrome P-450IA1 (EROD) activity in a dose-dependent manner and the lack of induction 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.