Sarabia V, Ramlal T, Klip A
Division of Cell Biology, Hospital for Sick Children, Toronto, Ont., Canada.
Biochem Cell Biol. 1990 Feb;68(2):536-42. doi: 10.1139/o90-076.
Human muscle cells were grown in culture from satellite cells present in muscle biopsies and fusion-competent clones were identified. Hexose uptake was studied in fused myotubes of human muscle cells in culture and compared with hexose uptake in myotubes of the rat L6 and mouse C2C12 muscle cell lines. Uptake of 2-deoxyglucose was saturable and showed an apparent Km of about 1.5 mM in myotubes of all three cell types. The Vmax of uptake was about 6000 pmol/(min.mg protein) in human cells, 4000 pmol/(min.mg protein) in mouse C2C12 muscle cells, and 500 pmol/(min.mg protein) in L6 cells. Hexose uptake was inhibited approximately 90% by cytochalasin B in human, rat, and mouse muscle cell cultures. Insulin stimulated 2-deoxyglucose uptake in all three cultures. The hormone also stimulated transport of 3-O-methylglucose. The sensitivity to insulin was higher in human and C2C12 mouse myotubes (half-maximal stimulation observed at 3.5 X 10(-9) M) than in rat L6 myotubes (half-maximal stimulation observed at 2.5 X 10(-8) M). However, insulin (10(-6) M) stimulated hexose uptake to a larger extent (2.37-fold) in L6 than in either human (1.58-fold) or mouse (1.39-fold) myotubes. It is concluded that human muscle cells grown in culture display carrier-mediated glucose uptake, with qualitatively similar characteristics to those of other muscle cells, and that insulin stimulates hexose uptake in human cells. These cultures will be instrumental in the study of human insulin resistance and in investigations on the mechanism of action of antidiabetic drugs.
从肌肉活检中提取的卫星细胞在培养条件下培育出人类肌肉细胞，并鉴定出具有融合能力的克隆。对培养的人类肌肉细胞融合肌管中的己糖摄取进行了研究，并与大鼠L6和小鼠C2C12肌肉细胞系的肌管中的己糖摄取进行了比较。在所有三种细胞类型的肌管中，2-脱氧葡萄糖的摄取是可饱和的，表观Km约为1.5 mM。人类细胞摄取的Vmax约为6000 pmol/(min·mg蛋白质)，小鼠C2C12肌肉细胞为4000 pmol/(min·mg蛋白质)，L6细胞为500 pmol/(min·mg蛋白质)。在人类、大鼠和小鼠肌肉细胞培养物中，细胞松弛素B可使己糖摄取受到约90%的抑制。胰岛素刺激了所有三种培养物中2-脱氧葡萄糖的摄取。该激素还刺激了3-O-甲基葡萄糖的转运。人类和C2C12小鼠肌管对胰岛素的敏感性高于大鼠L6肌管（在3.5×10⁻⁹ M时观察到半数最大刺激）（在2.5×10⁻⁸ M时观察到半数最大刺激）。然而，胰岛素（10⁻⁶ M）在L6中比在人类（1.58倍）或小鼠（1.39倍）肌管中更大程度地刺激己糖摄取（2.37倍）。得出的结论是，在培养条件下生长的人类肌肉细胞表现出载体介导的葡萄糖摄取，其性质与其他肌肉细胞相似，并且胰岛素刺激人类细胞中的己糖摄取。这些培养物将有助于研究人类胰岛素抵抗以及抗糖尿病药物的作用机制。
