A SIMPLE, DIFFERENTIAL EXTRACTION METHOD FOR THE SIMULTANEOUS DIRECT RADIOIMMUNOASSAY OF ANDROGENS AND ANDROGEN GLUCURONIDES IN HUMAN SERUM

A method is described for the differential extraction of unconjugated androgens (testosterone and dihydrotestosterone) and glucuronidated an drogens (androstane-3 alpha,17 beta-diol glucuronide and androsterone glucuronide) from human serum using solid-phase, gravity-flow extracti on columns. In this method, 100-mu L aliquots of serum are loaded onto the normal-phase columns, unconjugated androgens are eluted with ethy l ether, and glucuronides are eluted with ethyl ether containing 2% ac etic acid. Glucuronide eulates are washed with 1% aqueous acetic acid to remove cross-reacting steroid sulfates. Assays of sera for the four steroids were performed using standard radioimmunoassay methodology, except for androsterone glucuronide. This steroid was assayed with a n ovel radioimmunoassay method that employs a tritiated, unconjugated an drosterone tracer and an anti-dehydroepiandrosterone sulfate antiserum . The new method is well suited for the assay of conjugated and unconj ugated steroids in large numbers of specimens, particularly where the sample volume is limited.