Enhancement of Liver Microsome Epoxide Hydratase Activity in Rodents by Treatment with 2(3)-tert-Butyl-4-hydroxyanisole

Administration of the antioxidant 2(3)- tert -butyl-4-hydroxyanisole (BHA) in the diet caused a marked increase in the specific activity of epoxide hydratase (EC 4.2.1.63) in hepatic microsomes of CD-1 mice. The increases in epoxide hydratase activities produced by BHA were far greater (11-fold) than were those produced by the administration of well-known enzyme inducers such as 3-methylcholanthrene, phenobarbital, and Aroclor 1254 (2- to 3-fold). The near-maximal increase in epoxide hydratase activity was observed after feeding of the BHA diet for 3 days. When BHA was administered by gastric intubation, the level of increase was only 75% of that attained by feeding BHA in the diet. The increase in epoxide hydratase activity produced by BHA treatment of Sprague-Dawley rats was not as pronounced (<3-fold) as that observed in CD-1 mice.