Human GLUT-2 overexpression does not affect glucose-stimulated insulin secretion in MIN6 cells.
Accumulated evidence suggests that GLUT-2, in addition to its role in glucose transport, may also have other functions in glucose-stimulated insulin secretion. As a first step in addressing this possibility, we have engineered MIN6 cells overexpressing human GLUT-2 by transfection with human GLUT-2 cDNA. Stable transformants harboring human GLUT-2 cDNA exhibited an approximately twofold increase in 3-O-methyl-D-glucose uptake at 0.5 and 15 mM. Glucokinase activity or glucose utilization measured by conversion of [5-3H]glucose to [3H]H2O was not, however, altered in the MIN6 cells overexpressing human GLUT-2. Furthermore, glucose-stimulated insulin secretion was not affected by over-expression of human GLUT-2. An abundance of GLUT-2, therefore, does not correlate with the glucose responsiveness of cells in which glycolysis is regulated at the glucose phosphorylating step. These data suggest that GLUT-2 by itself does not have significant functions other than its role in glucose transport in glucose sensing by MIN6 cells.
D019325:3-O-Methylglucose; D002460:Cell Line; D005947:Glucose / Q000378:metabolism / Q000494:pharmacology*; D051273:Glucose Transporter Type 2; D006801:Humans; D007328:Insulin / Q000378:metabolism*; D000078790:Insulin Secretion; D007515:Islets of Langerhans / Q000378:metabolism*; D008757:Methylglucosides / Q000493:pharmacokinetics; D009004:Monosaccharide Transport Proteins / Q000378:metabolism*; D010766:Phosphorylation; D013347:Subcellular Fractions / Q000378:metabolism; D014018:Tissue Distribution; D014162:Transfection
D051273:Glucose Transporter Type 2; D007328:Insulin; D008757:Methylglucosides; D009004:Monosaccharide Transport Proteins; D019325:3-O-Methylglucose; D005947:Glucose