Peripheral conversion and uptake of androgens in a XXY-man with Klinefelter's syndrome.

The conversion of 3H-testosterone and the uptake of 3H-testosterone and 3H-5alpha-dihydrotestosterone were investigated in pubic skin and pubic hair follicles of a XXY-man with inadequate pubic hair. The uptake of both androgens was demonstrated in the skin as well as in the hair follicles. Similarly the activity of steroid 5alpha-reductase was present in both tissues. The total conversion of 3H-testosterone was 2-3 times higher in the patient than in control persons. In the XXY-man the major metabolites were 5alpha- and 5beta-androstanediols, whereas in the normal men 5alpha-dihydrotestosterone and 4-androstenedione were mainly formed from testosterone. An explanation of the inadequate growth of pubic hair in our patient seems to be related to a conversion of testosterone - at its low plasma level - to its relatively inactive metabolites.