Correlation of gonadotropins with unbound testosterone during puberty in males.

The longitudinal change in the percentage binding of testosterone has been studied in 137 serum samplings from 41 pubertal males. Free (unbound) testosterone levels were also calculated and total and free testosterone levels evaluated according to the stage of sexual development and correlated with LH and FSH levels obtained concomitantly. There was a progressive rise of total and free testosterone levels throughout puberty closely correlated with pubic hair staging. Serum LH levels correlated significantly with both total and free testosterone levels while serum FSH correlated with total but not free testosterone levels.