Eicheler W, Happle R, Hoffmann R
Philipp University, Department of Dermatology, Marburg, Germany.
Arch Dermatol Res. 1998 Mar;290(3):126-32. doi: 10.1007/s004030050277.
Hair growth depends on a close interaction of different cell populations of the hair follicle. In certain regions of the body, androgens interfere with this highly regulated cooperation in a yet poorly understood manner. The response of hair follicles to androgens can be categorized as androgen-dependent, e.g. in the beard, androgen-sensitive, e.g. in the frontal scalp of affected individuals, or androgen-independent, e.g. in the occipital scalp. At the target cell level, the balance between 5 alpha-reductase, 17 beta-hydroxysteroid-dehydrogenase (17 beta-HSD) and 3 alpha-hydroxysteroid dehydrogenase (3 alpha-HSD) yields metabolites with different androgenic potential. We examined this target cell-specific androgen metabolism in microdissected intact sub-units of dermal papillae, connective tissue sheaths (CTS) and root sheaths. In dermal papillae, 5 alpha-reductase predominated with an accumulation of the strong androgen 5 alpha-dihydrotestosterone. The specific activity of 5 alpha-reductase in the papillae exceeded those in the other hair follicle compartments by a factor of at least 14 in the scalp (5.4, 0.4 and 0.1 pmol/h per mm3 in the papilla, CTS and root respectively and at least 80 in the beard (16.0, 0.2 and 0.4 pmol/h per mm3 in the papilla, CTS and root respectively). The root sheath keratinocytes expressed low 5 alpha-reductase levels, but high 17 beta-HSD levels, with androstenedione as the major metabolite. The CTS expressed both 5 alpha-reductase and 17 beta-HSD, resulting in androstenedione, 5 alpha-androsterone and 5 alpha-androstanedione. In the CTS and the root sheath, only minor amounts of 5 alpha-DHT were found. In beard papillae, the 5 alpha-reductase activity was three times that in the occipital scalp papillae. These results indicate that the androgen response of hair follicles depends on a differentiated intrafollicular androgen metabolism and that the dermal papilla might be a primary target in this process.
毛发生长依赖于毛囊中不同细胞群的紧密相互作用。在身体的某些部位，雄激素以一种尚未完全理解的方式干扰这种高度调节的协同作用。毛囊对雄激素的反应可分为雄激素依赖性，如在胡须部位；雄激素敏感性，如在受影响个体的额部头皮；或雄激素非依赖性，如在枕部头皮。在靶细胞水平，5α-还原酶、17β-羟基类固醇脱氢酶（17β-HSD）和3α-羟基类固醇脱氢酶（3α-HSD）之间的平衡产生具有不同雄激素活性的代谢产物。我们在显微切割的完整真皮乳头、结缔组织鞘（CTS）和根鞘亚单位中研究了这种靶细胞特异性雄激素代谢。在真皮乳头中，5α-还原酶占主导地位，强效雄激素5α-双氢睾酮积累。头皮中乳头内5α-还原酶的比活性比其他毛囊区域至少高14倍（乳头、CTS和根中分别为5.4、0.4和0.1 pmol/h per mm3），胡须中至少高80倍（乳头、CTS和根中分别为16.0、0.2和0.4 pmol/h per mm3）。根鞘角质形成细胞表达低水平的5α-还原酶，但17β-HSD水平高，主要代谢产物为雄烯二酮。CTS同时表达5α-还原酶和17β-HSD，产生雄烯二酮、5α-雄甾酮和5α-雄烷二酮。在CTS和根鞘中，仅发现少量的5α-DHT。在胡须乳头中，5α-还原酶活性是枕部头皮乳头中的三倍。这些结果表明，毛囊的雄激素反应取决于毛囊内分化的雄激素代谢，真皮乳头可能是这一过程中的主要靶点。
