Hormonal control of 5 alpha-reductase activity in hamster sebaceous glands

The effect of castration on total 5 alpha-reductase activity in transforming testosterone to 5 alpha-reduced metabolites was studied in the sebaceous gland of male hamsters. The mean enzyme activity increased to more than twice the control level as early as 4 days after castration and this increase remained almost unchanged at 14, 21 and 63 days after castration. The administration of testosterone propionate or 5 alpha-dihydrotestosterone to castrates led to a complete inhibition of the increase in enzyme activity and this inhibitory effect was blocked by cyproterone acetate. These data indicate that androgens may be regulators of 5 alpha-reductase activity in the sebaceous gland of hamsters.