Inhibition by an Anti-androgen of Stimulation Provided by Four Androgenic Compounds

Employing inunction of the chick comb, studies of the stimulation afforded by 3 different androgens showed that testosterone acetate and androsterone acetate were equipotent and 3–4 times as active as dehydroepiandrosterone acetate. Dosages of these 3 androgens were selected which stimulated the same amount of comb growth and the comb was simultaneously inuncted with an anti-androgen, cyproterone acetate (Cyp A). Over a range of 10 to 80 μg, Cyp A inhibited to the same extent (approximately 30%) the growth of comb produced by any of these 3 androgens. In systemic treatment, employing subcutaneous injections, Cyp A also counteracted to the same extent the stimulation provided by any of these 3 androgens, and by androstenedione. The degree of inhibition was greater with systemic than with topical use of Cyp A. Since Cyp A (or the free alcohol, cyproterone) inhibits the androgenic stimulation provided by 4 compounds which are believed to represent the major androgens (and their derivatives) secreted by teste...