In-vitro contractility of human seminiferous tubules in response to testosterone, dihydrotestosterone and estradiol.

The effects of steroids (testosterone, dihydrotestosterone and estradiol) on human seminiferous tubules in vitro were ascertained by recording the intratubular pressure with a servonull micropressure measuring device. We describe here the first response of the human seminiferous tubule to steroids. Testosterone and dihydrotestosterone had a biphasic effect on tubular contractility. Higher doses of both testosterone and dihydrotestosterone induced contractions of the seminiferous tubules whereas lower doses of these compounds induced relaxation. Estradiol (10(-9) M to 10(-6) M) induced relaxation of the seminiferous tubules in a dose-dependent manner. The results from these experiments suggested that steroids may be involved in the control of contraction of the human seminiferous tubule and may regulate the movement of spermatozoa from the testes.