The 5alpha-reductase type 1, but not type 2, gene is expressed in anagen hairs plucked from the vertex area of the scalp of hirsute women and normal individuals

Abstract

The aim of the present study was to determine the expression of the genes for type 1 (SDR5A1) and type 2 (SDR5A2) 5α-reductase isoenzymes in scalp hairs plucked from 33 hirsute patients (20 with polycystic ovary syndrome and 13 with idiopathic hirsutism) and compare it with that of 10 men and 15 normal women. SDR5A1 and SDR5A2 expression was estimated by RT-PCR using the gene of the ubiquitously expressed protein ß 2 -microglobulin as an internal control. The results are expressed as arbitrary units in relation to ß 2 -microglobulin absorbance (mean ± SEM). SDR5A2 expression was not detected in any hair samples analyzed in this study. No differences were found in SDR5A1 mRNA levels between men and normal women (0.78 ± 0.05 vs 0.74 ± 0.06, respectively). SDR5A1 gene expression in the cells of hair plucked from the scalp of normal women (0.85 ± 0.04) and of women with polycystic ovary syndrome (0.78 ± 0.05) and idiopathic hirsutism (0.80 ± 0.06) was also similar. These results indicate that SDR5A1 gene expression in the follicular keratinocytes from the vertex area of the scalp seems not to be related to the differences in hair growth observed between normal men and women and hirsute patients. Further studies are needed to investigate the expression of the 5α-reductase genes in other scalp follicular compartments such as dermal papillae, and also in hair follicles from other body sites, in order to elucidate the mechanism of androgen action on the hair growth process and related diseases.

Idiopathic hirsutism: local and peripheral expression of aromatase (CYP19A) and 5α-reductase genes (SRD5A1 and SRD5A2)

“…There are several differences in study design that can explain the contrast between our results and those of Oliveira et al (13). They analyzed SRD5A expression in plucked anagen hairs but not in the connective tissue sheath, the lower bulb, the dermal papilla cells, and the sebaceous gland; we isolated the dermal papillae.…”

“…Previously, Sultan et al (12) and Oliveira et al (13) used RT-PCR to investigate SRD5A1 and SRD5A2 expression in plucked scalp hairs from hirsute patients (13 idiopathic and 20 with PCOS) and controls (10 men and 15 nonhirsute women). Their study did not detect SRD5A2 expression in hair samples and found no differences in SRD5A1 expression between any of the groups.…”

“…Their study did not detect SRD5A2 expression in hair samples and found no differences in SRD5A1 expression between any of the groups. With these results, they argued that SRD5A1 gene expression is not responsible for differences in hair growth in normal men, normal women, or hirsute patients, with the caveat that more detailed studies including other follicular compartments would be necessary (13).…”

Altered Transcription Profiles of Key-Enzymes of Androgen Biosynthesis in Genital Skin Fibroblasts from Patients with 46,XY Disorders of Sex Development (DSD)

“…To date, some studies already investigated mRNA expression of sex steroid biosynthesis enzymes in different androgen-dependent tissues from healthy humans and also from patients with different diseases [English et al, 2000;Kim et al, 2002;Provost et al, 2002;Blouin et al, 2003;Labrie et al, 2003;Oduwole et al, 2003;Oliveira et al, 2003;Quinkler et al, 2003Quinkler et al, , 2004Stoffel-Wagner, 2003]. This includes reproductive dysfunction and polycystic ovary syndrome (PCOS) and also various malignancies [Koh et al, 2002;Gunnarsson et al, 2003;Labrie et al, 2003;Vihko et al, 2003].…”

Identification of 5α‐reductase isoenzymes in canine skin

“…Androgenic alopecia in humans involves DHT production from local activity of 5α‐reductase isoenzymes in the skin of affected areas . We have shown for the first time, to the best of the authors' knowledge, that 5αR1 and 5αR3 – but not 5αR2 – are expressed in the skin of healthy dogs.…”