Role of Gq alpha in insulin-stimulated glucose uptake by C6 glioma cells.
To investigate the possibility that insulin-stimulated glucose uptake in C6 cells is due to transactivation of a G protein-mediated pathway, the role of Gq alpha in insulin signaling was studied. Insulin stimulation of [3H]2-deoxy-D-glucose (2DG) uptake by C6 cells was time- and concentration-dependent: at a concentration of 1 microM, insulin stimulated 2DG uptake by C6 cells by about 30% (p < 0.05). Pertussis toxin treatment of C6 cells did not alter the ability of insulin (1 microM) to promote 2DG uptake, ruling out the involvement of Gion in insulin-stimulated hexose uptake. Next, C6 cells were transfected with Gq alpha cDNA for 48 h, challenged with 1 microM insulin, and 2DG uptake by the cells was determined. Insulin-stimulated 2DG uptake was 1.14 +/- 0.03 and 1.75 +/- 0.19 nmol/min/mg protein in mock- and Gq alpha-transfected cells, respectively (p < 0.05); insulin stimulated 2DG uptake in Gq alpha-transfected cells by 54%. These results suggest an involvement of Gq alpha in the transactivation of the G protein signal transduction pathway by insulin.
Singh
S P
SP
Endocrine-Metabolic Division, Veterans Affairs Medical Center, Chicago, IL, USA.
Gao
Y
Y
Kunapuli
S P
SP
Ravindra
R
R
D003847:Deoxyglucose / Q000378:metabolism*; D019204:GTP-Binding Proteins / Q000502:physiology*; D005910:Glioma / Q000378:metabolism*; D007004:Hypoglycemic Agents / Q000494:pharmacology*; D007328:Insulin / Q000494:pharmacology*; D037342:Pertussis Toxin; D015398:Signal Transduction / Q000187:drug effects*; D014407:Tumor Cells, Cultured; D010566:Virulence Factors, Bordetella / Q000494:pharmacology
D007004:Hypoglycemic Agents; D007328:Insulin; D010566:Virulence Factors, Bordetella; D003847:Deoxyglucose; D037342:Pertussis Toxin; D019204:GTP-Binding Proteins