Effect of oral isotretinoin treatment on skin androgen receptor levels in male acneic patients.

An oral daily dose (mean +/- SD, 0.75 +/- 0.05 mg/kg) of isotretinoin was administered for 3 months to six male patients with acne (scores of 4 and 5 according to Rosenfield). The therapy resulted in complete resolution of acne in four patients and improved acne significantly (score 1) in two patients. In accordance with recent findings, no change in serum testosterone and significant decreases in 5 alpha-dihydrotestosterone, 5 alpha-androstane-3 alpha,17 beta-diol glucosiduronate, and androsterone glucosiduronate levels were observed after treatment. Androgen receptor status was investigated in back skin biopsies obtained in acne areas before and after 3 months of isotretinoin treatment. The treatment did not modify the binding affinity constant of skin androgen receptor (0.44 vs. 0.32 nmol/L), but it did induce a 2.6-fold decrease in its binding capacity constant (62 vs. 24 fmol/mg cytosolic protein), as assessed by Scatchard plot and confirmed immunologically by Western blot analysis. These data clearl...