Testicular function in Klinefelter's syndrome.

Testicular venous effluent was obtained by selective catheterization from 2 subjects with chromatin-positive Klinefelter's syndrome. In both of these subjects the testosterone concentration was reduced, whereas the estradiol concentration was normal or slightly increased in 1 and reduced to a much lesser extent than the testosterone level in the other. The testosterone/estradiol ratios in both subjects were in the range of 180, whereas in the normal subjects the mean testosterone/estradiol ratio in the spermatic venous effluent was 582.