Effect of diet on the hepatotoxicity of polybrominated biphenyls (FireMaster PB-6)

The consumption of diets formulated with Cruciferae vegetables, e.g., cauliflower, cabbage, and Brussels sprouts, has been shown to result in a stimulation of the intestinal and hepatic microsomal enzyme systems in rats. This study was designed to determine if this increase in intestinal and hepatic microsomal enzyme activity affected the hepatic response to polybrominated biphenyls (PBB). After three weeks of consuming either a semipurified or 25% cauliflower leaf-supplemented diet (CLD), male Sprague-Dawley rats were maintained for an additional 20 days on their respective diets containing either 0, 1, or 50 ppm PBB. A significant decrease in body weights, but not feed efficiency, was observed over all levels of PBB in animals consuming CLD compared to semipurified diets; consumption of up to 50 ppm of PBB had no effect on body weights with either diet. Relative liver weights (RLW), hepatic aryl hydrocarbon hydroxylase (AHH), N- and O-demethylase, as well as intestinal AHH were all increased in CLD-consuming animals before the addition of PBB. While PBB supplementation alone resulted in increased RLW, hepatic AHH, N- and O-demethylase, microsomal protein, and cytochrome P-450, rats consuming cauliflower diets + PBB had even higher RLW and N- and O-demethylase activity and microsomal protein concentrations. Hepatic PBB residue and total hepatic lipids were significantly reduced in CLD groups receiving 50 ppm PBB. These results suggest that the antitoxic effects of certain vegetables are related to more rapid metabolism and excretion of xenobiotic compounds.