Effect of dietary butylated hydroxyanisole on the mouse hepatic monooxygenase system of nuclear and microsomal fractions.

The effect of butylated hydroxyanisole (BHA) administration on the hepatic monooxygenase system of nuclear and microsomal fraction was investigated in male mice. Addition of BHA to the diet significantly lowered the content of cytochrome P-450 in liver nuclei and increased the specific activity of NADPH-cytochrome c reductase and the content of cytochrome b5 in liver microsomes. Incubation of benzo[a]pyrene (BP) with liver nuclei from BHA-fed mice resulted in inhibition of binding of BP metabolites to nuclear macromolecules by 50% compared with control. However, there was no effect of BHA on the binding of BP metabolites to macromolecules when BP was incubated with added DNA and liver microsomes from BHA-fed mice. It has been postulated that modification of nuclear monooxygenases by BHA may play a role in the inhibitory effect of BHA on BP carcinogenesis.