17 alpha-Propylmesterolone (SH 434): an antiandrogenic sebosuppressive substance not influencing circulating testosterone concentrations. Experimental studies in Syrian hamsters.

17 alpha-Propylmesterolone is a new synthetic 5 alpha-reduced steroid with a propyl group in C-17 position and a methyl group in the A ring. The antiandrogenic action of 17 alpha-propylmesterolone on the sebaceous glands, testes weights and plasma testosterone concentrations were examined in the animal model of the Syrian hamster. The substance was given systemically (3, 5 or 10 mg/kg) and topically (3 or 5 mg/kg). 17 alpha-propylmesterolone reduced both sebaceous gland size and sebogenesis significantly in a dose-dependent manner. The topical administration was more effective than the systemic treatment. There was no influence of 17 alpha-propylmesterolone on testosterone concentration in plasma or testes weights although a diminished capacity or absence of free cytoplasmatic androgen receptor sites was detected in the sebaceous glands of the systematically or topically treated Syrian hamster. 17 alpha-Propylmesterolone exerts a potent topical sebosuppressive effect in the animal model. These findings should give rise to human studies and clinical trials.