Thornton M J, Laing I, Hamada K, Messenger A G, Randall V A
Department of Biomedical Sciences, University of Bradford, West Yorks, UK.
Clin Endocrinol (Oxf). 1993 Dec;39(6):633-9. doi: 10.1111/j.1365-2265.1993.tb02420.x.
Androgens have paradoxically different effects on hair follicles depending on body site, stimulating beard growth while inducing regression in some areas of the scalp. The mesenchyme derived dermal papilla at the base of the hair follicle regulates many aspects of the growth of follicular epithelium, and is probably the site of androgen action. Since 5 alpha-dihydrotestosterone is considered to be the active intracellular androgen in many target tissues and is required for some androgen-mediated hair growth, such androgen-sensitive cells should contain 5 alpha-reductase. This study was designed to investigate whether cultured human dermal papilla cells contain 5 alpha-reductase and whether the metabolic capacity varies with the body site of the follicle in line with the clinical picture.
Testosterone metabolism in cultured dermal papilla cells from androgen sensitive beard follicles was compared with less androgen dependent non-balding scalp follicles. Primary cell cultures were established from follicles of 11 patients with normal hair growth. The cells were grown to confluence in 10-cm Petri dishes and incubated with 5 nM 3H-testosterone in serum-free medium for 2 hours. The cells and the culture medium were collected separately for individual analysis.
Unlabelled carrier and 14C-marker steroids were added to both the cell and medium extracts before separation by thin-layer chromatography. The individual steroid identities were confirmed by recrystallizing up to five times to a constant 3H/14C ratio.
Testosterone was taken up by both cell types; significant amounts of 5 alpha-dihydrotestosterone were recovered inside beard cells, but not in scalp cells, whereas androstenedione was identified in both. An unidentified compound was present intracellularly in both cell types, but was not present in the culture medium. 5 alpha-Dihydrotestosterone was present only in the culture medium of beard cells but androstenedione was present in a similar amount in the medium from both cell types. The presence of other steroids could not be confirmed in either the cell extracts or the culture medium.
The production of 5 alpha-dihydrotestosterone by beard cells concurs with the poor beard growth in men with 5 alpha-reductase deficiency, supporting our hypothesis that androgens mediate their effects on the hair follicle via the mesenchyme-derived dermal papilla.
雄激素对毛囊的影响因身体部位而异，呈现出矛盾的差异，它能刺激胡须生长，却会导致头皮某些区域的毛囊退化。毛囊底部由间充质衍生而来的真皮乳头调节着毛囊上皮生长的多个方面，可能是雄激素作用的位点。由于5α - 双氢睾酮被认为是许多靶组织中具有活性的细胞内雄激素，且是某些雄激素介导的毛发生长所必需的，因此这种雄激素敏感细胞应含有5α - 还原酶。本研究旨在调查培养的人真皮乳头细胞是否含有5α - 还原酶，以及其代谢能力是否根据毛囊的身体部位不同而有所变化，以符合临床情况。
将雄激素敏感的胡须毛囊培养的真皮乳头细胞中的睾酮代谢情况与雄激素依赖性较低的非秃头皮毛囊进行比较。从11名头发生长正常的患者的毛囊中建立原代细胞培养。细胞在10厘米的培养皿中生长至汇合，然后在无血清培养基中与5纳摩尔的3H - 睾酮孵育2小时。分别收集细胞和培养基进行单独分析。
在通过薄层色谱分离之前，向细胞和培养基提取物中加入未标记的载体和14C标记的类固醇。通过重结晶多达五次至恒定的3H/14C比率来确认各个类固醇的身份。
两种细胞类型均摄取睾酮；在胡须细胞内回收了大量的5α - 双氢睾酮，但头皮细胞中未回收，而两种细胞中均鉴定出雄烯二酮。两种细胞类型的细胞内均存在一种未鉴定的化合物，但培养基中不存在。5α - 双氢睾酮仅存在于胡须细胞的培养基中，但雄烯二酮在两种细胞类型的培养基中的含量相似。在细胞提取物或培养基中均无法确认其他类固醇的存在。
胡须细胞产生5α - 双氢睾酮与5α - 还原酶缺乏男性的胡须生长不良情况相符，支持了我们的假设：雄激素通过间充质衍生的真皮乳头对毛囊发挥作用。
