Increased androgen receptor messenger RNA in frontal-parietal hair follicles of women with androgenetic alopecia.

Normal testosterone levels are frequently observed in women with androgenetic alopecia (AGA), suggesting the involvement of androgen sensitivity in this condition. Androgen sensitivity is related to androgen receptor (AR) messenger RNA (mRNA) production in hair follicles and is negatively related to the number of CAG repeats present in exon 1 of the AR gene. The aim of this study was to compare AR expression in AGA women with normal controls and to correlate this expression with the number of CAG repeats. Hair follicles were obtained from 27 women with AGA and 21 controls for AR gene expression analysis. AR expression was evaluated through AR mRNA quantification using real-time polymerase chain reaction and the number of CAG repeats in the AR gene was determined in complementary DNA samples obtained from hair follicles and analyzed with the Gene Scan software. AR mRNA in the frontal-parietal region was significantly higher than in the occipital region of AGA patients (paired t-test, P = 0.046). No significant difference was identified in controls (P = 0.67). Both regions in the same individual showed a significant positive correlation in AGA patients (r = 0.77; P < 0.05) and in controls (r = 0.91; P < 0.05). A negative correlation was identified between AR expression and the number of CAG repeats only in AGA patients (r = 0.510; P = 0.013). The identification of elevated AR mRNA quantitation in hair follicles is a useful tool for identifying potentially abnormal androgen sensitivity in AGA patients.