Catalytic activities of cytochrome P-450 from female rat liver: correlation with sex differences in drug metabolism in diabetic liver.

Sodium dodecyl sulfate-polyacrylamide gel electrophoresis of detergent solubilized cytochrome P-450 fractions from normal and diabetic female rat liver microsomes revealed the induction of a 52,000 molecular weight microsomal hemeprotein in diabetic liver. Two major P-450 hemeproteins (DB IIA and DB IIB) were subsequently isolated from solubilized diabetic female rat hepatic P-450 fractions, while normal rat liver yielded only one major microsomal P-450, N IIA. When examined in a reconstituted drug metabolizing system, the aniline hydroxylation rate catalyzed by DB IIB (52,000 molecular weight) was 157% and 78% greater than the rates catalyzed by N IIA and DB IIA, respectively. The rates of ethylmorphine metabolism catalyzed by N IIA and DB IIB were similar; however, the rate of ethylmorphine metabolism catalyzed by DB IIA (54,000 molecular weight) was approximately 42% greater than the rates catalyzed by either N IIA or DB IIB. These results are compared to those previously obtained with P-450s isolated from diabetic male rat liver and indicate that diabetes induces P-450s with specific catalytic activities which can account for both the sex-dependent and sex-independent alterations in drug metabolism observed in diabetic rat liver.