Possible Age-Dependent Influence of Estrogens on the Binding of Testosterone in Plasma of Adult Men

Abstract

The possible influence of estrogens on the increased binding of testosterone in plasma of adult men with progressing aged was examined. In 104 men, 17 to 89 years old, the plasma concentrations of estrone and estradiol were measured by radioimmunoassay and the percentage of binding of testosterone by equilibrium dialysis. The same samples were also aalysed for the concentrations of Cortisol as measured by competitive protein binding and the percentage of binding of Cortisol. While no influence of age on the latter two parameters was observed, the percentage of binding of testosterone increased from 91.4 ± 1.2% in the 17 to 50 year old men (group 1) to 93.6 ± 1.4% in the 51 to 89 year old (group 2). Estrone and estradiol increased from 28.8 ± 5.3 pg/ml and 19.7 ± 3.9 pg/ml plasma respectively in group 1 to 40.5 ± 8.4 pg/ml and 29.7 ± 7.3 pg/ml in group 2. There was a significant (p < 0.001) correlation between the increase in estrogens and binding of testosterone.

Key words

Estrone - Estradiol - Cortisol - Percentage of Binding of Testosterone/Cortisol - Plasma - Age Dependence - Man