CHANGES IN LEYDIG CELL HYDROXYSTEROID DEHYDROGENASES INDUCED BY ADMINISTRATION OF TESTOSTERONE PROPIONATE TO NORMAL MEN
SUMMARY By the employment of an improved histochemical technique, frozen sections from human testicular biopsy specimens were examined for 3β-and 17β-hydroxysteroid dehydrogenase (HSD) activity, before, during, and after administration of 25 or 50 mg testosterone propionate per day to normal men. This administration strongly suppressed Leydig cell HSD activity and caused these cells to be transformed into fibroblast-like cells. After cessation of administration, the Leydig cells recovered morphologically and so did, simultaneously their 3β- and 17β-HSD activity. It is concluded that histochemically detectable 3β- and 17β-HSD are under gonadotrophin control and change with alterations in Leydig cell function. The morphology or 3β- and 17β-HSD are therefore probably acceptable as indicators of Leydig cell function in reproductively normal men.