THE RESPONSE OF THE SEBACEOUS GLANDS OF THE HYPOPHYSECTOMIZED—CASTRATED MALE RAT TO 5α-DIHYDROTESTOSTERONE, ANDROSTENEDIONE, DEHYDROEPIANDROSTERONE AND ANDROSTERONE

5α-Dihydrotestosterone and androstenedione (0·2 mg/24 h for 24 days), but not testosterone, significantly increased sebum production in hypophysectomized—castrated rats. Dehydroepiandrosterone and androsterone, even in doses ten times greater, could not be shown to do so, though all the steroids increased the incidence of mitoses in the sebaceous glands. In rats with intact pituitaries, however, the greatest effect on sebaceous secretion was produced by testosterone. A significant increase was also produced by 5α-dihydrotestosterone; androstenedione was only effective at ten times the dose, and androsterone was without significant effect. Dehydroepiandrosterone was not tested.A possible interpretation of the results is that within the sebaceous glands, either the release of testosterone from its conjugates or its conversion to an active metabolite is under pituitary control. The results also support the view that there are at least two distinct points of action of steroids on the sebaceous glands, namely mitosis and intracellular synthesis of sebum.