Effects of gliquidone on glucose uptake in C2C12 cells

Objective To investigate the effects of gliquidone on glucose uptake and the expression of glucose transporter 4 (GLUT4) in C2C12 myotubes. Methods Cultured C2C12 myotubes were used for glucose consumption studies. The groups were as follows: control group, 1×10-5 mol/L gliquidone group, 1×10-7 mol/L insulin group and 1×10-5 mol/L gliquidone+ 1×10-7 mol/L insulin group. Glucose concentrations in medium were determined by the glucose oxidase method. The amount of glucose consumption was calculated by the glucose concentrations of blank wells subtracting the remaining glucose in cell plated wells. Scintillation was used to detect the glucose uptake of C2C12 myotubes. The expression of GLUT4 mRNA was tested by real-time PCR (RT-PCR). One-way ANOVA was used for data analysis. Results Glucose consumption of C2C12 myotubes was significantly increased with 1×10-5 mol/L gliquidone ((11.0±0.5) vs (7.9±0.6) mmol/L, q=0.36, P<0.01). With the existence of gliquidone, the glucose-lowering effect of 1×10-7 mol/L insulin was strengthened. Compared to the control cells, insulin, gliquidone, gliquidone+ insulin, and glibenclamide increased 2-deoxyglucose uptake (q values were 14.78, 11.30 and 5.00, all P<0.01) in C2C12 myotubes after incubation for 12 h with the indicated drug concentrations. The gliquidone-stimulated glucose uptake of mytubes was higher than that with the glibenclamide-stimulated (q=6.30, P<0.01), and the insulin-stimulated glucose uptake was distinctly elevated in the presence of gliquidone (q=5.43, P<0.01). Gliquidone did not enhance the expression of GLUT4 mRNA in C2C12 myotubes. Conclusion Gliquidone stimulates glucose uptake, increases the insulin-stimulated glucose uptake in C2C12 myotubes, but has no effect on the expression of GLUT4 mRNA. Key words: Gliquidone; Glucose; Glucose transporter 4