Itami S, Kurata S, Takayasu S
Department of Dermatology, Medical College of Oita, Japan.
J Invest Dermatol. 1990 Jan;94(1):150-2. doi: 10.1111/1523-1747.ep12874003.
The activity of 5 alpha-reductase was assessed in cultured human beard dermal papilla cells and reticular dermal fibroblasts to elucidate the mechanism of androgen action in promoting the growth of beards in men. The monolayer was incubated with 50 nM of [1,2-3H]-testosterone. Steroids were extracted from the medium and analyzed by thin layer chromatography. The major metabolite in the beard dermal papilla cells was dihydrotestosterone (DHT), the most potent androgen in the androgen target tissue. By contrast, the amount of DHT formed was similar to that of androstenedione in reticular dermal fibroblasts. The 5 alpha-reductase activity in beard dermal papilla cells was three to five times as high as that in the reticular dermal fibroblasts from the same skin sample. The apparant Michaelis constant of 5 alpha-reductase in the beard dermal papilla cells was 1.0 X 10(-6) M, which was virtually equivalent to that of genital skin fibroblasts, typical androgen target cells. It was 4.0 X 10(-5) M in reticular dermal fibroblasts. By contrast, the activities of 5 alpha-reductase in dermal papilla cells from occipital scalp hair follicles were similar to those of reticular dermal fibroblasts of the same skin samples. These results strongly suggest that the beard dermal papilla cell is an androgen target cell, and that DHT plays a role in the growth of beards in men.
为了阐明雄激素促进男性胡须生长的作用机制，研究人员对培养的人胡须真皮乳头细胞和网状真皮成纤维细胞中的5α-还原酶活性进行了评估。将单层细胞与50 nM的[1,2-³H]睾酮一起孵育。从培养基中提取类固醇，并通过薄层色谱法进行分析。胡须真皮乳头细胞中的主要代谢产物是双氢睾酮（DHT），它是雄激素靶组织中最有效的雄激素。相比之下，在网状真皮成纤维细胞中形成的DHT量与雄烯二酮的量相似。来自同一皮肤样本的胡须真皮乳头细胞中的5α-还原酶活性是网状真皮成纤维细胞中的三到五倍。胡须真皮乳头细胞中5α-还原酶的表观米氏常数为1.0×10⁻⁶ M，这实际上与典型的雄激素靶细胞——生殖器皮肤成纤维细胞的米氏常数相当。在网状真皮成纤维细胞中，该常数为4.0×10⁻⁵ M。相比之下，枕部头皮毛囊真皮乳头细胞中5α-还原酶的活性与同一皮肤样本的网状真皮成纤维细胞中的活性相似。这些结果有力地表明，胡须真皮乳头细胞是雄激素靶细胞，并且DHT在男性胡须生长中起作用。
