Testosterone concentration within the tunica vaginalis of boys and adult men.

The testosterone level in fluid contained in the tunica vaginalis has been determined in 25 adult men referred for infertility and in 20 boys aged 0-10.5 years operated on for hydrocele. The median concentrations of testosterone were found to be 392 nmole/1 (range 78-957) and 1.1 nmole/1 (range 0.16-182), respectively. The median value for adult men was 20 times the concentration of testosterone found in the peripheral blood of that group while the median value for the boys was 4 times that found in their peripheral blood. It is concluded, firstly, that the high level of testosterone in the peritesticular space of adult men strongly indicates that diffusion of testosterone through the testicular capsule does take place. Secondly, testosterone levels in fluid from the peritesticular space which significantly exceeds those in peripheral blood in prepubertal boys furnishes evidence of testicular secretion of testosterone in that age group. Consequently, the peritesticular tissues such as the epididymis, gubernaculum and scrotum are exposed to quantities of testosterone far exceeding those brought by the general circulation.