McFarland D C, Pesall J E, Gilkerson K K
Department of Animal and Range Sciences, South Dakota State University, Brookings 57007-0392.
Gen Comp Endocrinol. 1993 Mar;89(3):415-24. doi: 10.1006/gcen.1993.1049.
The influence of growth factors on the proliferation and differentiation of clonal-derived embryonic myoblasts and satellite cells was examined in hormonally controlled serum-free media. Although insulin-like growth factor-I (IGF-I) and IGF-II each stimulated proliferation of both cell types, IGF-II was the more potent mitogen for embryonic myoblasts (P < or = 0.05). Exogenously added IGFs also stimulated differentiation of embryonic myoblasts (P < or = 0.05) but did not influence the differentiation of satellite cells (P > or = 0.05). Fibroblast growth factor (FGF) was required for proliferation of either cell type to occur. Platelet-derived growth factor-BB acted synergistically with IGF-I and FGF to stimulate proliferation. Unlike human muscle cells, neither avian satellite cells nor embryonic myoblasts responded to epidermal growth factor. The influence of IGFs and insulin on IGF-binding protein (IGFBP) release from myogenic cells was also examined. Both cell types secreted a major binding protein of 34 kDa and a second protein of 36 kDa. Satellite cells secreted a prominent IGFBP at 30.8 kDa, while embryonic myoblasts secreted higher molecular weight forms of 37 and 41 kDa. Highest IGFBP release was seen when cells from either type were administered IGF-II. Equimolar levels of IGF-I or insulin stimulated IGFBP release, however, at levels lower than that induced by IGF-II. Release of IGFBP was nearly undetectable in the presence of cycloheximide (50 micrograms/ml), suggesting that protein synthesis was necessary for IGFBP release.
在激素控制的无血清培养基中研究了生长因子对克隆来源的胚胎成肌细胞和卫星细胞增殖及分化的影响。尽管胰岛素样生长因子-I（IGF-I）和IGF-II均刺激了两种细胞类型的增殖，但IGF-II对胚胎成肌细胞是更强效的促有丝分裂原（P≤0.05）。外源性添加的IGF也刺激了胚胎成肌细胞的分化（P≤0.05），但不影响卫星细胞的分化（P≥0.05）。两种细胞类型的增殖都需要成纤维细胞生长因子（FGF）。血小板衍生生长因子-BB与IGF-I和FGF协同作用以刺激增殖。与人类肌肉细胞不同，禽卫星细胞和胚胎成肌细胞均对表皮生长因子无反应。还研究了IGF和胰岛素对成肌细胞释放IGF结合蛋白（IGFBP）的影响。两种细胞类型均分泌一种主要的34 kDa结合蛋白和第二种36 kDa的蛋白。卫星细胞分泌一种突出的30.8 kDa的IGFBP，而胚胎成肌细胞分泌分子量更高的37 kDa和41 kDa的形式。当给两种类型的细胞施用IGF-II时，观察到最高的IGFBP释放。然而，等摩尔水平的IGF-I或胰岛素刺激IGFBP释放，但水平低于IGF-II诱导的水平。在存在环己酰亚胺（50微克/毫升）的情况下，几乎检测不到IGFBP的释放，这表明蛋白质合成对于IGFBP释放是必需的。
