Effect of isotretinoin on serum levels of precursor and peripherally derived androgens in patients with acne.

Sebaceous glands are stimulated by androgens and can convert them to more active forms. Isotretinoin, however, has a profound inhibitory effect on sebaceous gland size and function. This study evaluated the effect of isotretinoin on serum levels of precursor and tissue-derived androgens. Twenty-four subjects (15 men and nine women) were treated for 20 weeks with 1 mg/kg/d of isotretinoin. Serum samples were obtained at baseline, 8, 16, and 24 weeks, and assayed for precursor androgens--total testosterone (TT), free testosterone (free T), dehydroepiandrosterone (DHEA), dehydroepiandrosterone-sulfate (DHEA-S); and tissue androgens--dihydrotestosterone (DHT), and its metabolite, 3 alpha-androstanediol glucuronide (3 alpha-diol G). Isotretinoin had no meaningful effects on precursor androgens, except for producing an elevation of free T in women. In contrast, isotretinoin produced depressions in the serum levels of DHT and 3 alpha-diol G in women and in 3 alpha-diol G in men. These decreases are believed to be the result, rather than the cause, of a reduction in the size of the sebaceous glands: The magnitude of the observed decreases may represent the amount of tissue-derived androgens that sebaceous glands normally contribute to the circulating pool.