DELTA-5-ANDROSTENEDIOL - KINETICS OF METABOLISM AND BINDING TO PLASMA-PROTEINS IN NORMAL MEN AND WOMEN

Using the constant infusion and single injection technique, metabolic clearance rates (mean .+-. SEM [standard error of the mean]) for .DELTA.5-androstene-3.beta., 17.beta.-diol (.DELTA.5-diol) were measured for 19 normal men (1311 .+-. 67 1/24 h) and 10 normal women (858 .+-. 63 1/24 h). The constant infusion technique yielded values for the conversion ratios for the transformation of .DELTA.5-diol to several products: dehydroepiandrosterone (DHEA)/.DELTA.5-diol for 0.06 .+-. 0.01 for men and 0.05 .+-. 0.01 for women, of .DELTA.5-diol sulfate/.DELTA.5-diol of 0.45 .+-. 0.04 for men and 0.52 .+-. 0.03 for women and of DHEA sulfate/.DELTA.5-diol of 5.53 .+-. 0.26 for men and 5.02 .+-. 0.42 for women. The single injection technique yielded rate constants (units) and volumes of distribution (liters) for .DELTA.5-diol; K1 = 34.3 .+-. 4.3 for men and 35.0 .+-. 3.9 for women, K2 = 63.7 .+-. 4.1 for men and 75.1 .+-. 4.2 for women, V1 = 23.1 .+-. 3.2 for men and 11.9 .+-. 2.3 for women, V2 = 14.8 .+-. 3.7 for men and 9.2 .+-. 3.2 for women. The mean .DELTA.5-diol plasma concentration was 1.08 .+-. 0.10 ng/ml for 12 men and 1.17 .+-. 0.16 ng/ml for 9 women. The calculated blood production rates for .DELTA.5-diol were 1357 .+-. 117 .mu.g/24 h for 12 men and 969 .+-. 131 .mu.g/24 h for 9 women. The percent binding (equilibrium dialysis) was higher for women (94.9 .+-. 0.3) than for men (93.0 .+-. 0.2). Paper electrophoresis showed that significant fractions of 3H-.DELTA.5-diol migrated with both the .beta.-globulin and albumin fractions. Estrogen administration to 2 normal men increased the percent binding of .DELTA.5-diol to plasma proteins and decreased the metabolic clearance rate towards the values found for normal women.