Effect of administration of Aroclor 1254 on the activities of hepatic drug metabolizing enzymes in zinc deficiency.
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.
Food and Drug Toxicology Research Centre, National Institute of Nutrition, Hyderabad, India.
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Jagadeesan
D000818:Animals; D001140:Aroclors / Q000633:toxicity*; D001579:Benzopyrene Hydroxylase / Q000187:drug effects; D001835:Body Weight / Q000187:drug effects; D020111:Chlorodiphenyl (54% Chlorine); D004851:Epoxide Hydrolases / Q000187:drug effects; D005982:Glutathione Transferase / Q000187:drug effects; D008099:Liver / Q000187:drug effects* / Q000201:enzymology; D008297:Male; D008862:Microsomes, Liver / Q000187:drug effects / Q000201:enzymology; D009929:Organ Size / Q000187:drug effects; D051381:Rats; D011919:Rats, Inbred Strains; D015032:Zinc / Q000097:blood / Q000172:deficiency*
D001140:Aroclors; D020111:Chlorodiphenyl (54% Chlorine); D001579:Benzopyrene Hydroxylase; D005982:Glutathione Transferase; D004851:Epoxide Hydrolases; D015032:Zinc