AnImaJS and Treatments with Inducers. Fifteen male Wistar rats

Dietary antioxidants protect laboratory animals against the induction of tumors by a variety of chemical carcinogens. Among possible media nisms, protection against chemical cardnogenesis could be mediated via antioxidant-dependent induction of detoxifying enzymes. Therefore, we investigated the effects of two commonly used food preservatives, butyl ated hydroxyanisole (BHA) and butylated hydroxytoluene (BHT), on the expression of @P-glucuronssyltransferase isoforms In rat liver. Male Wistar rats were fed a control diet or diets containing BRA (0.75%) or BHT (0.5%) for 2 weeks. BHT and BHA increased UDP-glucuronosyl transferase activities in liver microsomes for p-nltrophenol (236 and 218%, respectively), 3-hydroxybenzo(a)pyrene (246 and 175%, respec tively), and androsterone (269 and 152%, respectively). Immunoblots showed changes in the amounts of UDP-glucuronosyltransferase isoforms corresponding to the changes in enzyme activities. Northern blot analysis showed that the concentration of UDP-glucumnosyltransferase mRNA paralleled the concentrationofenzyme proteinsand their respectivelevels of enzyme activity. BHT, for example, caused about a 250% increase in mRNA using a probe that recognizes the common 3'-domaln of bffirubin/ phenol UDP-glucuronosyltransferase mRNAs. In addition to indudng hepatic enzyme activities, BHT and BHA increased the activity of UDP-glucuronosyltransferase in the small intestine and kidney.