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Mechanism of action of androgen in human hair follicles

雄激素在人毛囊中的作用机制

基本信息

批准号：
06670872
负责人：
ITAMI Satoshi
金额：
$ 1.34万
依托单位：
Osaka University (1995)大分医科大学 (1994)
依托单位国家：
日本
项目类别：
Grant-in-Aid for General Scientific Research (C)
财政年份：
1994
资助国家：
日本
起止时间：
1994 至 1995
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-06670872/
关键词：
Hair Dermal papilla cells Androgen 5alpha-reductase Androgen receptor IGF-I

项目摘要

In order to study the mechanism of action of androgen in human hair follicles, we examined the expressions of androgen receptor, type I and type II 5alpha-reductase in cultured human hair follicle cells. Beard dermal papilla cells possess a higher 5alpha-reductase activity and a larger amount of androgen receptors than reticular dermal fibroblasts or dermal papilla cells from the occipital scalp. Besides, the enzyme found in beard dermal papilla cell appears to be type 2 5alpha-reductase. In contrast, outer root sheathe cells do not have characteristics of the target cells. Androgen significantly stimulates the proliferation of outer root sheath cells that are cocultured with beard dermal papilla cells without cell contact. The expression of insulin-like growth factorI (IGF-I) mRNA in beard dermal papilla cells was stimulated by androgen and antagonized by cyproterone acetate. Outer root sheath cells did not express mRNA for IGF-I either in the presence or absence of androgen. Both of these two types of cells expressed mRNA for IGF-I receptor and the expression was not affected by androgen. Neutralizing antibody against IGF-I antagonized the stimulatory effect of androgen on the growth of outer root sheath cell cocultured with beard dermal papilla cells. These findings suggest that IGF-I is a candidate for androgen induced hair growth factors.

为了研究雄激素在人毛囊中的作用机制，我们检测了培养的人毛囊细胞中雄激素受体、I型和II型5 α-还原酶的表达。胡须毛乳头细胞具有较高的5 α-还原酶活性和大量的雄激素受体比网状真皮成纤维细胞或枕部头皮毛乳头细胞。此外，在胡须毛乳头细胞中发现的酶似乎是2型5 α-还原酶。相反，外根鞘细胞不具有靶细胞的特征。雄激素显著刺激与胡须毛乳头细胞共培养的外根鞘细胞的增殖，而无细胞接触。雄激素可刺激胡须毛乳头细胞胰岛素样生长因子I（IGF-I）mRNA的表达，醋酸环丙孕酮可拮抗这种作用。无论有无雄激素，外根鞘细胞均不表达IGF-I mRNA。这两种细胞均表达IGF-I受体mRNA，且其表达不受雄激素的影响。IGF-1中和抗体可拮抗雄激素对与胡须毛乳头细胞共培养的外根鞘细胞生长的刺激作用。这些发现表明IGF-I是雄激素诱导的毛发生长因子的候选者。