Effect of administration of Aroclor 1254 on the activities of hepatic drug metabolizing enzymes in zinc deficiency.

ABSTRACT

In order to understand the mechanisms of carcinogenesis in zinc deficiency, a study was conducted in experimental animals to investigate the effect of administration of an inducer. After the production of zinc deficiency in NIN/Wistar strain of rats by feeding an egg albumin-starch based diet almost devoid of zinc, the animals were administered a potent inducer of mixed-function oxidases Aroclor 1254 and various Phase I and Phase II enzymes of drug metabolism like benzo[a]pyrene hydroxylase, microsomal epoxide hydrolase, cytosolic epoxide hydrolase, and cytosolic glutathione-S-transferase studied in liver tissues. Control and pair-fed groups were also run alongside. The results showed that while the activities of various enzymes studied were low in the uninduced basal condition, these activities increased many-fold after induction. This induction was observed not only in the control group, but in the pair-fed and deficient groups as well. These results suggest that the ability to respond to a carcinogenic insult, though initially present in zinc deficiency, may not be adequate to counteract an excess or chronic exposure to carcinogen in the long run.