Thornton M J, Hibberts N A, Street T, Brinklow B R, Loudon A S, Randall V A
Department of Biomedical Sciences, University of Bradford, UK.
J Endocrinol. 2001 Mar;168(3):401-8. doi: 10.1677/joe.0.1680401.
Red deer stags produce an androgen-dependent mane of long hairs only in the breeding season; in the non-breeding season, when circulating androgen levels are low, the neck hair resembles the rest of the coat. This study was designed to determine whether androgen receptors are present in deer follicles throughout the year or only in the mane (neck) follicles when circulating testosterone levels are high in the breeding season. Although androgens regulate much human hair growth the mechanisms are not well understood; they are believed to act on the hair follicle epithelium via the mesenchyme-derived dermal papilla. The location of androgen receptors in the follicle was investigated by immunohistochemistry and androgen binding was measured biochemically in cultured dermal papilla cells derived from mane and flank follicles during the breeding season and from neck follicles during the non-breeding season. Immunohistochemistry of frozen skin sections using a polyclonal antibody to the androgen receptor localised nuclear staining only in the dermal papilla cells of mane follicles. Saturation analysis assays of 14 primary dermal papilla cell lines using [(3)H]-mibolerone demonstrated high-affinity, low-capacity androgen receptors were present only in mane (breeding season neck) cells; competition studies with other steroids confirmed the specificity of the receptors. Androgen receptors were not detectable in cells from either the breeding season flank nor the non-breeding season neck follicles. The unusual biological model offered by red deer of androgen-dependent hair being produced on the neck in the breeding, but not the non-breeding season, has allowed confirmation that androgen receptors are required in follicle dermal papilla cells for an androgen response; this concurs with previous human studies. In addition, the absence of receptors in the non-breeding season follicles demonstrates that receptors are not expressed unless the follicle is responding to androgens. Androgen receptors may be induced in mane follicles by seasonal changes in circulating hormone(s).
马鹿雄鹿仅在繁殖季节长出依赖雄激素的长毛鬃毛；在非繁殖季节，当循环雄激素水平较低时，颈部毛发与身体其他部位的毛发相似。本研究旨在确定雄激素受体是全年都存在于鹿毛囊中，还是仅在繁殖季节循环睾酮水平较高时存在于鬃毛（颈部）毛囊中。尽管雄激素调节人类的许多毛发生长，但其机制尚未完全了解；人们认为雄激素通过间充质来源的真皮乳头作用于毛囊上皮。通过免疫组织化学研究毛囊中雄激素受体的位置，并在繁殖季节取自鬃毛和胁腹毛囊以及非繁殖季节取自颈部毛囊的培养真皮乳头细胞中进行生化雄激素结合测定。使用抗雄激素受体的多克隆抗体对冷冻皮肤切片进行免疫组织化学分析，结果显示仅在鬃毛毛囊的真皮乳头细胞中有核染色。使用[³H] - 米勃龙对14个原代真皮乳头细胞系进行饱和分析测定，结果表明高亲和力、低容量的雄激素受体仅存在于鬃毛（繁殖季节颈部）细胞中；与其他类固醇的竞争研究证实了受体的特异性。在繁殖季节胁腹毛囊或非繁殖季节颈部毛囊的细胞中均未检测到雄激素受体。马鹿提供了一种不寻常的生物学模型，即依赖雄激素的毛发在繁殖季节而非非繁殖季节出现在颈部，这证实了毛囊真皮乳头细胞中需要雄激素受体才能产生雄激素反应；这与先前的人类研究结果一致。此外，非繁殖季节毛囊中缺乏受体表明，除非毛囊对雄激素作出反应，否则受体不会表达。循环激素的季节性变化可能会诱导鬃毛毛囊中的雄激素受体。
