5 alpha reductase in hair follicles

drcole

Yuji Asada, Tadashige Sonoda, Mayumi Ojiro, Sotaro Kurata, Toshihiro Sato, Tetsuo Ezaki and Susumu Takayasu

Department of Dermatology (Y.A., T.So., M.O., S.K., T.Sa., S.T.), Oita Medical University; and Ezaki Clinic (T.E.), Oita 879-5593 , Japan

Address all correspondence and requests for reprints to: Yuji Asada, M.D., Oita Medical University, Department of Dermatology, 1-1 Daigaoka, Hasama-Machi, Oita 879-5593, Japan. E-mail: asada@oita-med.ac.jp.

Abstract

Recent studies suggest that 5{alpha}-reductase type 2 (5{alpha}R2) rather than 5{alpha}R1 plays a key role in the pathogenesis of male-pattern baldness. To clarify the localization of the androgen receptor (AR), 5{alpha}R1, and 5{alpha}R2 in the hair follicle, we investigated the expression of the corresponding genes by RT-PCR using microdissected hair follicles. AR and 5{alpha}R1 mRNAs were expressed in all portions of the hair follicle. By contrast, 5{alpha}R2 mRNA was expressed only in mesenchymal portions that included the dermal papilla and connective tissue sheath, and hardly any was expressed in epithelial portions. The intensity of expression of these genes in each portion of the hair follicles did not differ between follicles from balding and nonbalding scalp. We also examined the expression of these genes in cultured fibroblasts derived from the dermal papilla and connective tissue sheath. Although expression of AR and 5{alpha}R1 mRNAs was easily detected, there was no obvious expression of 5{alpha}R2 mRNA in either type of cell. Type-specific inhibition of 5{alpha}R activity by MK386 and MK906 confirmed these patterns of expression of 5{alpha}R mRNA. Thus, the expression of 5{alpha}R2 mRNA seems to be characteristic of freshly microdissected mesenchymal portions of the hair follicle, but such expression might not be maintained in culture.