Testosterone concentration in different functional compartments of the male reproductive tract

The concentration of testosterone in testicular tissue (TT), spermatic vein blood (SVB), cubital blood (CB), and seminal fluid (SF) was estimated using a radioimmunoassay technique in a total of 50 normospermic, oligozoospermic, and azoospermic men. Testosterone was also determined in cauda epididymis-vas deferens ductus wash fluid (WF) in 6 normospermic men. In 2 oligozoospermic men the testosterone concentration in TT was 556 and 725 ng/g tissue, respectively. In 9 normospermic men the mean SVB testosterone concentration was 473 ng/ml. CB and SF concentrations of this steroid were 6.8 and 0.4 ng/ml in normospermic, 6.4 and 0.5 ng/ml in oligozoospermic, and 4.9 and 0.4 ng/ml in azoospermic men, respectively; the difference among the three groups was not significant. The SVB:CB and SVB:SF ratios in normospermic men were 71 and 1549, respectively, while the CB:SF ratio was 18 in normospermic, 18 in oligozoospermic, and 16.6 in azoospermic men. Testosterone could not be detected in individual specimens of WF, but after pooling of samples a concentration of 0.08 ng/ml WF was estimated. These results demonstrate the relative concentrations of testosterone in the different functional compartments of the reproductive tract in man and facilitate a better understanding of its function.