Reappraisal of the liver benzpyrene hydroxylase synthesized de novo after treatment of rats with 2,3,7,8-tetrachlorodibenzo-p-dioxin and 3-methylcholanthrene.

The dynamics of the inductive effects of MC and TCDD upon rat liver microsomal benzpyrene hydroxylase and the main properties of the de novo synthesized hemoproteins have been compared. The inadequacy of expression of the enzyme activity per total cytochrome P-448 content has been established. It was concluded that TCDD microsomes have a relatively low content of benzpyrene hydroxylase with a higher molecular activity than the enzyme from MC microsomes.