3a,1 l~-Dihydroxy-A4-androsten-17-one has been identified as a metabolite of 1 10-hydroxy-A4-androstene-3,17-dione in man. Its epimer, 3P,1 1P-dihydroxyd 4-androsten-17-one, was also isolated from urine but it was shown to be derived from the 3a-S tudies of the metabolism of labeled 1 lp-hydroxy-A4-androstene-3,17-dione (I) demonstrated variable amounts of acid-labile metabolites with the chromatographic mobility of 1 lp-hydroxyetiocholanolonel (11) . These products were observed with normal people and very small amounts were produced by hyperthyroid subjects. The new metabolites were, however, greatly increased in the urine of hypothyroid subjects and in some instances represented as much as 25% of the administered hormone. These metabolites have now been isolated and characterized as 3a,l 1~-dihydroxy-A4-androsten-17-one (IIIa) and its 3P-hydroxy epimer IVa. This report is a description of an isolation study made in a representative patient; it is similar in all pertinent details to a number of other investigations of the metabolic fate of 1 lp-hydroxy-A4-androstene-3,17-dione given to men and women, in large and small amounts, intravenously or orally. Trivial names and abbreviations used: 116-hydroxyetiocholanolone, 3a,ll~-dihydroxy-5~-androstan-17-one; 1 16-hydroxyandrosterone, 3a, 1 16-dihydroxy-5a-androstan-17-one; tlc, thin layer chromatography. hydroxy compound during the mild acid conditions of hydrolysis. The unsaturated metabolite was excreted in conjugated form which could be cleaved by treatment at pH 5.0 at 45 O for 1 day. Longer periods of incubation resulted in a 1 : 1 equilibrium mixture of the two epimers. 0 H I I1 RO '. & Ro& IIIa, R = H IVa,R=H b,R=Ac b,R=Ac c , R = C H~ AcO"' &dP v VI Procedure A man with myxedema, V. R., age 67, was given 840 mg of 1 l~-hydroxy-A4-androstene-3,17-dione-1,2-~H (16,909 cpm/mg) dissolved in 24 ml of absolute alcohol by continuous intravenous drip at a rate of 2-3 ml/day for 10 days. Urine was collected during administration 1779
