Hamada K, Thornton M J, Laing I, Messenger A G, Randall V A
Department of Biomedical Sciences, University of Bradford, United Kingdom.
J Invest Dermatol. 1996 May;106(5):1017-22. doi: 10.1111/1523-1747.ep12338582.
Androgens regulate the growth of many human hair follicles, but only pubic, axillary, and scalp hair growth occur in men with 5 alpha-reductase deficiency. This suggests that 5 alpha-dihydrotestosterone is the active intracellular androgen in androgen-dependent follicles, except in the axilla and pubis. Since the dermal papilla plays a major regulatory role in hair follicles and may be the site of androgen action, we have investigated androgen metabolism in six primary lines of cultured dermal papilla cells from pubic and axillary hair follicles; previous studies have shown that beard cells take up and metabolize testosterone, retaining and secreting 5 alpha-dihydrotestosterone. After 24 h preincubation in serum-free Eagle's medium 199, 100-mm dishes of confluent cells were incubated for 2 h with 5 nM [1,2,6,7-3H]testosterone. Media were collected and the cells washed with phosphate-buffered saline and extracted with chloroform: methanol (2:1). After the addition of unlabeled and 14C-labeled marker steroids, the extracts were analyzed by a two-step thin-layer chromatography system; steroid identity was confirmed by recrystallization to a constant 3H/14C ratio. Beard and pubic dermal papilla cells were also incubated for 24 h, and the medium was analyzed at various times. The results from pubic and axillary primary cell lines were similar. In both cells and media the major steroid identified was testosterone, but significant amounts of androstenedione were present, indicating 17 beta-hydroxysteroid dehydrogenase activity; androstenedione was also identified within the cells, but a small amount of 5 alpha-dihydrotestosterone was only identified in one pubic cell line. Beard dermal papilla cells secreted large amounts of 5 alpha-dihydrotestosterone into the medium over 24 h in contrast to pubic cells, which produced only very small amounts. The pubic and axillary cell results contrasts with the observations of pronounced 5 alpha-dihydrotestosterone in beard cells and confirm that androgen metabolism in cultured dermal papilla cells reflects the parent follicle's ability to respond to androgen in the absence of 5 alpha-reductase type II in vivo. This supports our hypothesis that androgen acts on hair follicles via the dermal papilla and suggests that cultured dermal papilla cells may offer an important model system for studies of androgen action.
雄激素调节许多人类毛囊的生长，但在患有5α-还原酶缺乏症的男性中，只有阴毛、腋毛和头皮毛发生长。这表明，除了腋窝和耻骨部位，5α-双氢睾酮是雄激素依赖性毛囊中的活性细胞内雄激素。由于真皮乳头在毛囊中起主要调节作用，且可能是雄激素作用的部位，我们研究了来自阴毛和腋毛毛囊的6个原代培养真皮乳头细胞系中的雄激素代谢；先前的研究表明，胡须毛囊细胞摄取并代谢睾酮，保留并分泌5α-双氢睾酮。在无血清伊格尔培养基199中预孵育24小时后，将长满细胞的100毫米培养皿与5 nM [1,2,6,7-3H]睾酮孵育2小时。收集培养基，用磷酸盐缓冲盐水洗涤细胞，并用氯仿：甲醇（2:1）提取。加入未标记和14C标记的标记类固醇后，提取物通过两步薄层色谱系统进行分析；通过重结晶至恒定的3H/14C比值来确认类固醇的身份。胡须和阴毛真皮乳头细胞也孵育24小时，并在不同时间分析培养基。阴毛和腋毛原代细胞系的结果相似。在细胞和培养基中鉴定出的主要类固醇都是睾酮，但存在大量雄烯二酮，表明存在17β-羟类固醇脱氢酶活性；细胞内也鉴定出了雄烯二酮，但仅在一个阴毛细胞系中鉴定出少量5α-双氢睾酮。与阴毛细胞仅产生极少量5α-双氢睾酮不同，胡须真皮乳头细胞在24小时内将大量5α-双氢睾酮分泌到培养基中。阴毛和腋毛细胞的结果与胡须细胞中明显存在5α-双氢睾酮的观察结果形成对比，并证实了培养的真皮乳头细胞中的雄激素代谢反映了体内缺乏II型5α-还原酶时母毛囊对雄激素的反应能力。这支持了我们的假设，即雄激素通过真皮乳头作用于毛囊，并表明培养的真皮乳头细胞可能为雄激素作用的研究提供一个重要的模型系统。
