THE METABOLISM OF [1,2-3H]17α-METHYLTESTOSTERONE IN HUMAN SUBJECTS

Abstract

SUMMARY The metabolism of [1,2-3H] 17α-methyltestosterone (MeT) has been studied in adult human subjects, most of whom had cancer of the breast. The rates of disappearance of MeT from plasma and of the appearance of metabolites of MeT in plasma have been measured after intravenous injection of [1,2-3H]MeT. In addition, the rate of appearance of [1,2-3H]MeT and of metabolites of MeT in urine and in faeces has been measured after intravenous injection of [1,2-3H]MeT and in urine after oral administration of the steroid. The results show that MeT is metabolized more slowly than testosterone. Identification of metabolites of MeT which were isolated from the urine of patients to whom this steroid was administered has been attempted. Three compounds, 17α-methyl-5β-androstane-3α,17β-diol (tetrahydro-MeT), 17α-methyl-5α-androstane-3α,17β-diol (allotetrahydro-MeT) and unchanged MeT have been identified, three other compounds have been partially characterized and several others have been isolated. The most abundant metabolites of MeT are hydroxylated compounds reduced in ring A.