Delta 5-androstenediol: kinetics of metabolism and binding to plasma proteins in normal post-menopausal women.

Delta 5-androstenediol (delta 5-diol) while having minimal androgenic activity is of potential biological importance because it binds to oestrogen receptors and has oestrogenic activity in several systems. We have examined delta 5-diol metabolism in post-menopausal women utilizing the constant infusion technique. The metabolic clearance rate for 11 subjects was 763 +/- 50 1/24 h or 467 +/- 30 1/m2/24 h. Labelled dehydroepiandrosterone, testosterone, delta 4-androstenedione, androsterone and the sulphates of delta 5-diol, dehydroepiandrosterone and androsterone were found in the plasma. Of all the kinetic parameters only the conversion ratio for dehydroepiandrosterone sulphate was different from that for young women (4.958 +/- 0.410 for young women vs 3.084 +/- 0.220 for older women). The plasma concentration of delta 5-diol was 0.94 +/- 0.19 ng/ml and the calculated blood production rate was 686 +/- 80 micrograms/24 h. The per cent free plasma delta 5-diol was 4.6 +/- 0.25. These values are slightly lower but not significantly different from those previously reported for normal young women.