Exclusive androgenic effect of dehydroepiandrosterone in sebaceous glands of rat skin

In order to analyze the hormonal effects of dehydroepiandrosterone (DHEA) i n skin sebaceous glands, the precursor steroid was administered to ovariect omized (OVX) female Sprague-Dawley rats at a dose of 30 mg applied on the d orsal skill, twice daily, for 3, 6 and 12 months. In a parallel experiment, female OVX rats were treated with DHEA at the same daily percutaneous dose of 30 mg, alone or in combination with the antiandrogen Flutamide or the p ure antiestrogen EM-800, for 12 months, in order to determine the androgeni c and/or estrogenic components of DHEA action. Treatment of female OVX rats with DHEA resulted in a similar mild to moderate hyperplasia of the sebace ous glands of both dorsal (site of application) and ventral skin, as illust rated by an increase in the number and size of the acini. The above-indicat ed effects were observed at all time intervals studied, bt ginning at 3 mon ths of treatment, and they were not further increased after longer term adm inistration of DHEA (for 6 and 12 months). The addition of Flutamide to DHE A treatment completely prevented the DHEA-induced changes in the sebaceous glands, whereas the antiestrogen EM-800 had no effect. The present data ind icate an exclusive androgenic stimulatory action of DHEA on the sebaceous g lands, thus pointing out the importance of local intracrine DHEA transforma tion into androgens for skin anatomical integrity and function, while showi ng that estrogens, if active in rat skin, do not originate from DHEA.