Asada Y, Sonoda T, Ojiro M, Kurata S, Sato T, Ezaki T, Takayasu S
Department of Dermatology, Oita Medical University, Japan.
J Clin Endocrinol Metab. 2001 Jun;86(6):2875-80. doi: 10.1210/jcem.86.6.7545.
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.
最近的研究表明，在男性型秃发的发病机制中起关键作用的是2型5α-还原酶（5αR2）而非1型5α-还原酶（5αR1）。为了明确雄激素受体（AR）、5αR1和5αR2在毛囊中的定位，我们使用显微切割的毛囊通过逆转录聚合酶链反应（RT-PCR）研究了相应基因的表达。AR和5αR1的信使核糖核酸（mRNA）在毛囊的所有部位均有表达。相比之下，5αR2的mRNA仅在包括真皮乳头和结缔组织鞘的间充质部分表达，在上皮部分几乎不表达。这些基因在秃发头皮和非秃发头皮毛囊各部分的表达强度没有差异。我们还检测了这些基因在源自真皮乳头和结缔组织鞘的培养成纤维细胞中的表达。虽然很容易检测到AR和5αR1的mRNA表达，但在这两种细胞中均未检测到5αR2的mRNA有明显表达。MK386和MK906对5αR活性的类型特异性抑制证实了5αR mRNA的这些表达模式。因此，5αR2的mRNA表达似乎是毛囊新鲜显微切割间充质部分的特征，但这种表达在培养中可能无法维持。
