Excretion of non-conjugated androstenedione and testosterone in human urine.

A method for the measurement of unconjugated testosterone and androstenedione in human urine is described. The method uses chromatographic separation followed by radioimmunoassay and has been examined for reliability. The mean 24-hour excretion of androstenedione by adult male subjects was 2.5 mug and of testosterone was 0.8 mug. For women, the mean excretion was 2.9 mug of androstenedione and 0.25 mug of testosterone. In pregnancy, androstenedione excretion was occasionally elevated above the normal range, but testosterone excretion was quite commonly increased. Some hirsute subjects exhibited an increase in androstenedione excretion, which was decreased by administration of dexamethasone. The results suggest that the amount of unconjugated testosterone in urine is not a direct reflection of the plasma free testosterone, but urinary androstenedione may be a useful reflection of plasma androstenedione levels.