Testosterone up-regulates androgen receptors and decreases differentiation of porcine myogenic satellite cells in vitro
Testosterone up-regulates androgen receptors and decreases differentiation of porcine myogenic satellite cells in vitro
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DOI：
10.1210/en.137.4.1385
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发表时间：
1996-04-01
期刊：
影响因子：
4.8
通讯作者：
Merkel, RA
中科院分区：
文献类型：
--
作者：
Doumit, ME;Cook, DR;Merkel, RA
DNA的积累是肌肉生长所必需的，但雄激素诱导的骨骼肌DNA增长的机制尚不清楚。本研究的目的是确定雄激素受体（AR）是否存在于培养的骨骼肌卫星细胞和肌管，并检查睾酮对卫星细胞增殖和分化的影响。使用多克隆AR抗体（PG-21）的免疫印迹分析显示，在猪卫星细胞和肌管的免疫反应性AR蛋白约107 kDa。免疫细胞化学AR染色仅限于卫星细胞、肌管和肌源性成纤维细胞的细胞核。将10（-7）M睾酮给予卫星细胞、肌管和肌源性成纤维细胞可增加免疫反应性AR。在卫星细胞和肌管中，AR在暴露于睾酮6、12和24小时后递增。睾酮（10（-10）-10（-6）M）单独或与胰岛素样生长因子I、碱性成纤维细胞生长因子或血小板衍生生长因子-BB组合对猪卫星细胞增殖没有影响（P > 0.1），睾酮预处理24 h并不改变细胞随后对这些生长因子的反应性。在用10（-7）M睾酮处理的第2-4天，卫星细胞分化被抑制（20-30%）。在停药并用对照培养基替代后48 h内，该效应不可逆。这些数据表明，卫星细胞是雄激素作用的直接靶点，睾酮给药增加免疫反应性AR蛋白，减少猪卫星细胞在体外的分化。
Accumulation of DNA is essential for muscle growth, yet mechanisms of androgen-induced DNA accretion in skeletal muscle are unclear. The purpose of this study was to determine whether androgen receptors (AR) are present in cultured skeletal muscle satellite cells and myotubes and examine the effects of testosterone on satellite cell proliferation and differentiation. Immunoblot analysis using polyclonal AR antibodies (PG-21) revealed an immunoreactive AR protein of approximately 107 kDa in porcine satellite cells and myotubes. Immunocytochemical AR staining was confined to the nuclei of satellite cells, myotubes, and muscle-derived fibroblasts. Administration of 10(-7) M testosterone to satellite cells, myotubes, and muscle-derived fibroblasts increased immunoreactive AR. In satellite cells and myotubes, AR increased incrementally after 6, 12, and 24 h of exposure to testosterone. Testosterone (10(-10)-10(-6) M), alone or in combination with insulin-like growth factor I, basic fibroblast growth factor, or platelet-derived growth factor-BB, had no effect (P > 0.1) on porcine satellite cell proliferation, and testosterone pretreatment for 24 h did not alter the subsequent responsiveness of cells to these growth factors. Satellite cell differentiation was depressed (20-30%) on days 2-4 of treatment with 10(-7) M testosterone. This effect was not reversible within 48 h after treatment withdrawal and replacement with control medium. These data indicate that satellite cells are direct targets for androgen action, and testosterone administration increases immunoreactive AR protein and reduces differentiation of porcine satellite cells in vitro.