Percentage of testosterone, androstenedione, and dehydroisoandrosterone bound to plasma protein in preadolescent children

Using equilibrium dialysis, the proportion of bound testosterone in plasma of 20 preadolescent children was found to be significantly higher than that in adult subjects. In contrast, the proportion of bound androstenedione and dehydroisoandrosterone was similar in children and adults. Sex had no effect on the binding of any of the three androgens. The total concentrations of testosterone, androstenedione, and dehydroisoandrosterone in peripheral plasma were measured by double isotope derivative technique in 2 separate pools from the 10 boys and 10 girls. Concentrations of unbound androgens were calculated. In prepubertal children, values for total and unbound androstenedione and dehydroisoandrosterone were both lower than in adults, the ratio, total to unbound, being similar in the two groups of subjects. Total concentrations of testosterone were also lower in children, but the unbound values were proportionally much lower as a result of the greater percentage of testosterone bound to protein in preadolescent children.