Effect of methyltestosterone administration on microsomal drug metabolism in aging rats.

The effects of methyltestosterone administration (100 mg/kg for four days) on the hepatic microsomal drug-metabolizing system from old male rats was investigated. Age-related decreases in cytochrome P-450 content, cytochrome c reductase activity and benzphetamine N-demethylase activity were unaffected by methyltestosterone treatment. Administration of the androgen induced nitroanisole O-demethylase and aniline hydroxylase activities, resulting in a restoration of the latter to levels found in young-adult animals.