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

Abstract

ABSTRACT. 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 Androgen receptor in androgenetic alopecia 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.

Androgens and androgen receptor action in skin and hair follicles

“…Normal testosterone levels are frequently observed in women with androgenetic alopecia (AGA), suggesting the involvement of androgen sensitivity in this condition. It was recently reported the increased AR messenger RNA expression in frontal-parietal hair follicles of women with AGA compared to controls [121] confirming the relation between androgen sensitivity and the AR mRNA production. Moreover, AR content in female frontal hair follicles is approximately 40% lower than in male counterparts.…”

Isolation and Quantification of Glycosaminoglycans from Human Hair Shaft

“…Dermal papilla cells from androgen dependent regions, contain higher levels of androgen receptors (AR) than those from androgen-insensitive areas 25 . Also, in women with androgenetic alopecia, increased AR expression in the FP region has been found (not observed in normal controls), proving the role of androgen hypersensitivity in this region 26 . Moreover, a second estrogen receptor, estrogen receptor β (ER β), present in androgen target tissues, as the prostate, has been also, identified in both male and female non balding human scalp skin 24 .…”

Polymorphic CAG Repeat Numbers in the Androgen Receptor Gene of Female Pattern Hair Loss in a Han Chinese Population

“…Richeti et al [26] showed that the level of mRNA in the AR at the frontal-parietal region in women with AGA was higher than the occipital region, and a significant negative correlation was observed between the amount of AR mRNA and the mean number of CAG repeats despite no significant difference in the control group. The study also indicated no significant difference in the CAG repeats between patients and controls, and suggested that the difference in expression of the AR gene could be attributed to the level of mRNA.…”