Effects of free fatty acids on the glucokinase and glucose transporter 2 expression and glucose stimulated insulin secretion in βTc6 cells

Abstract

Objective To investigate the changes of glucokinase (GK) and glucose transporter 2 (GLUT2) gene expression and insulin secretion induced by free fatty acid (FFA) in βTc6 cells. Methods βTc6 cells were cultured in vitro, treating with FFA (0.25, 0.5 and 1.0 mmol/L) for 24 hours, then examined GK and GLUT2 expression by real-time PCR and Western blot analysis. In addition the morphological change of βTc6 cells and the glucose stimulated insulin secretion (GSIS) were observed. Data analysis was assessed by using one-way ANOWA. Results (1)After intervening with 0.25 mmol/L FFA for 24 hours, no changes were found in the morphology and GSIS of βTc6 cell. There were no changes of the expression of GK and GLUT2 mRNA and protein in βTc6 cell(all P>0.05). (2)After intervening with 0.50-1.00 mmol/L FFA for 24 hours, the accumulation of lipid droplets in βTc6 cells was found in the cells, and cells mass showed the trend of disintegration. With the increase of FFA concentration, the above phenomenon was more visible, the expression of GK and GLUT2 mRNA decreased(GKFFA0.500.32±0.05 vs GKControl0.80±0.12; GLUT2FFA0.500.28±0.04 vs GLUT2Control0.72±0.11, GKFFA1.000.24±0.03 vs GKFFA0.500.32±0.05; GLUT2FFA1.000.21±0.03 vs GLUT2FFA0.500.28±0.04, all P<0.05), and GK and GLUT2 protein reducedgradually, GSIS also decreased gradually (all P<0.05). Conclusion FFA intervention with lower concentration can not affect the survival of βTc6 cells and GSIS and the expression of GK and GLUT2. But when FFA level increases abnormally β cells will be impaired the GK and GLUT2 expression and GSIS will be inhibited. Key words: Fatty acids, nonesterified; Glucose transporters type 2; Insulin; Glucokinase; βTc6 cell