Topical spironolactone inhibits dihydrotestosterone receptors in human sebaceous glands: an autoradiographic study in subjects with acne vulgaris.
Berardesca E, Gabba P, Ucci G, Borroni G, Rabbiosi G.
Department of Dermatology, University of Pavia, Italy.
The interaction between spironolactone and dihydrotestosterone (DHT) receptors was evaluated with an autoradiographic technique. The inhibition of DHT receptors by spironolactone was found to be related to the decrease of tritiated DHT granules in the sebaceous glands of the treated site. 6 male patients affected by acne vulgaris entered the study. The acute study was performed by applying to 25 cm2 of the back a cream containing 5% spironolactone under occlusive dressing. The dosage of spironolactone applied was 4 mg/cm2 for 48 h. The long-term study was performed by applying the same amount to the entire back, without occlusion, twice daily for 1 month. Skin biopsies were taken at the end of the treatment, incubated with tritiated DHT and processed for autoradiography. Both the acute and the long-term study revealed a decrease of the autoradiographic granules in the treated site. This effect is related to the binding of spironolactone with dihydrotestosterone receptors in the sebaceous glands.
Our study demonstrates that 5% topical spironolactone cream acts as an antiandrogen in human sebaceous glands, competing with DHT receptors and producing a decrease of labelled DHT. At the concentrations used the effect has been only local. No side-effects were recorded during both studies.