MARKED DECLINE IN SERUM CONCENTRATIONS OF ADRENAL C19 SEX STEROID PRECURSORS AND CONJUGATED ANDROGEN METABOLITES DURING AGING

The present data show a dramatic decline in the circulating levels of dehydroepiandrosterone (DHEA), DHEA-sulfate (DHEA-S), an drost-5-ene-3 beta,17 beta-diol (5-diol), 5-diol-sulfate, 6-diol-fatty acid esters, and androstenedione in both men and women between the ages of 30-80 y r. In the 50- to 60-yr-old group, serum DHEA decreased by 74% and 70% from its peak values in 20- to 30-yr-old men and women, respectively. The serum concentrations of the conjugated metabolites of dihydrotesto sterone (DHT), namely androsterone (ADT)-G, androstane-3 alpha,17 beta -diol (3 alpha-diol-G), androstane-3 beta,17 beta-diol (3 beta-diol-G) , and ADT-sulfate are the most reliable parameters of the total androg en pool in both men and women, whereas serum testosterone and DHT can be used as markers of testicular secretion in men and interstitial ova rian secretion in women. The serum concentration of these various conj ugated androgen metabolites: decreased by 40.8% to 72.8% between the 2 0- to 30-yr-old and 70- to 80-yr-old age groups in men and women, resp ectively, thus suggesting a pal allel decrease in the total androgen p ool with age. As estimated by measurement of the circulating levels of these conjugated metabolites of DHT, it is noteworthy that women prod uce approximately 66% of the total androgens found in men. In women, m ost of these androgens originate from the transformation of DHEA and D HEA-S into testosterone and DHT in peripheral intracrine tissues, wher eas in men the testes and DHEA and DHEA-S provide approximately equal amounts of androgens at the age of 50-60 yr. An additional potentially highly significant observation is that the majority of the marked dec line in circulating adrenal C-19 steroids and their resulting androgen metabolites takes place between the age groups of 20- to 30-yr olds a nd 50- to 60-yr-olds, with smaller changes are observed after the age of 60 yr.