Sato K, Kawai H, Naruo T, Yamaguchi H, Saito S
First Department of Internal Medicine, School of Medicine, University of Tokushima.
Rinsho Shinkeigaku. 1991 Aug;31(8):809-14.
The effects of A23187 (a substance acting on cell membrane) and cytochalasin B (a substance acting on cell structure) on the growth and differentiation of myoblasts (L6 cell) were examined using a cultured system. The L6 cells (1 x 10(5)) were incubated for 10 days in DMEM medium containing 10% fetal calf serum (a growth medium) by exchanging the medium every 3rd day. They showed no morphological differentiation and no increase in creatine kinase activity, myoglobin content and Ca2+ concentration. However, when L6 cells were incubated in DMEM medium containing 2% horse serum and 6 micrograms/ml insulin (an incubation medium for differentiation), they were morphologically differentiated into the myotube after 6-day culture with increase in creatine kinase activity, myoglobin content and Ca2+ concentration. In the presence of 40 nM A23187, no marked morphological change was observed in the L6 cells as compared with the control, but the myoglobin level rapidly increased to 18.2 x 10(-2) ng/micrograms (4.2-fold value of the control) at 10-day culture. In the presence of 200 nM cytochalasin B, there was no morphological change in the L6 cells, and no increase in the levels of creatine kinase and myoglobin. These data suggest that the function of the cell membrane and intracellular Ca2+ concentration play important roles in differentiating the muscle cells, because A23187 promotes biochemical differentiation of L6 cells as shown by increased myoglobin content.
利用培养系统研究了A23187（一种作用于细胞膜的物质）和细胞松弛素B（一种作用于细胞结构的物质）对成肌细胞（L6细胞）生长和分化的影响。将L6细胞（1×10⁵个）接种于含10%胎牛血清的DMEM培养基（生长培养基）中，每隔3天换液，培养10天。细胞未出现形态分化，肌酸激酶活性、肌红蛋白含量和Ca²⁺浓度也未增加。然而，当L6细胞在含2%马血清和6μg/ml胰岛素的DMEM培养基（分化培养基）中培养时，培养6天后细胞形态分化为肌管，同时肌酸激酶活性、肌红蛋白含量和Ca²⁺浓度增加。在40nM A23187存在的情况下，与对照组相比，L6细胞未观察到明显的形态变化，但在培养10天时，肌红蛋白水平迅速升高至18.2×10⁻²ng/μg（为对照组的4.2倍）。在200nM细胞松弛素B存在的情况下，L6细胞无形态变化，肌酸激酶和肌红蛋白水平也未增加。这些数据表明，细胞膜功能和细胞内Ca²⁺浓度在肌肉细胞分化中起重要作用，因为A23187可促进L6细胞的生化分化，表现为肌红蛋白含量增加。
