Decline of adrenal androgen production as measured by radioimmunoassay of urinary unconjugated dehyroepiandrosterone.

Dehydroepiandrosterone (DHA), in large part a measure of adrenal androgen secretion, previously has been measured in urine after hydrolysis or solvolysis of the glucuronide and sulfate conjugates. These procedures are time consuming; they often require several days and variable recoveries are a source of error. A method is presented here for determination of unconjugated DHA in 24-h urine specimens which requires less time, labor, and sample volume than necessary for the assay of DHA derived from conjugates. In 76 men and women, age 20-96 yr, total 24-h urinary unconjugated DHA showed no sex differences. However, the mean unconjugated DHA excretion decreased, which may indicate decreased zona reticularis function with respect to relatively constant zona fasiculata function in advancing age.