RADIOIMMUNOASSAY OF PLASMA ANDROSTENEDIONE, TESTOSTERONE AND 11 BETA-HYDROXYANDROSTENEDIONE AFTER CHROMATOGRAPHY ON LIPIDEX-5000 (HYDROXYALKOXYPROPYL SEPHADEX)

11β-Hydroxy androstenedione is a C29-steroid almost exclusively of endogenous adrenal origin. It represents a major pathway of biological inactivation of adrenal androstenedione, an important androgen precursor. If the proportion of biosynthesized adrenal androstenedione that becomes 11β-hydroxylated were constant, measurement of this product could serve as an indicator of the contribution of the adrenal to overall androstenedione production. For these reasons a procedure for the isolation of testosterone, androstenedione, and 11β-hydroxyandrostenedione by chromatography on Lipidex-5000, followed by radioimmunoassay measurement, has been developed and the analytical characteristics of the procedure evaluated. © 1978.