Hormones in seminal plasma.

Testosterone and prolactin play an important but unclear role in the process of spermatogenesis. Peripheral levels of these hormones are usually normal in infertile patients even when the characteristics of the sperm are subnormal. This study was conducted to evaluate the possible relationship between sperm quality and seminal content of testosterone and prolactin in 70 men. Men with normal semen analysis had venous blood levels of testosterone and prolactin that were not different from those seen in men with abnormal semen analysis while seminal concentration of testosterone was higher in the latter group of men. Testosterone concentration in semen from the 70 men investigated was 69 +/- 4 ng/100 ml, and in venous blood 487 +/- 20 ng/100 ml. However, in blood, one-third of this steroid was bound to testosterone binding globulin (TeBG), while no TeBG bound fraction of testosterone was found in seminal fluid. There was a direct correlation between the venous and seminal levels of these two hormones.