Contraction-induced translocation of the glucose transporter Glut4 in isolated ventricular cardiomyocytes.
Field stimulation of isolated adult ventricular cardiomyocytes was used to study the effect of contractile activity on 3-O-methylglucose transport and the subcellular distribution of Glut4. Cells contracting at a frequency of 1 Hz for 30 min exhibited unaltered basal and insulin-stimulated rates of glucose transport when compared to resting cells. However, at 5 Hz 3-O-methylglucose transport increased to 224% of control after 5 min. Under these conditions insulin was unable to produce a significant additional stimulation of glucose transport. Immunoblotting with an anti-Glut4 polyclonal antibody showed that both insulin and contraction (5 Hz) increased the amount of Glut4 in a plasma membrane fraction by about 8-fold with a parallel decrease in an intracellular membrane fraction by 60-65%. These data suggest the existence of an identical insulin- and contraction-recruitable Glut4 transporter pool in cardiomyocytes.
Kolter
T
T
Laboratory of Molecular Cardiology, Diabetes Research Institute, Düsseldorf, Germany.
Uphues
I
I
Wichelhaus
A
A
Reinauer
H
H
Eckel
J
J
D019325:3-O-Methylglucose; D000818:Animals; D015153:Blotting, Western; D002462:Cell Membrane / Q000378:metabolism; D002478:Cells, Cultured; D004558:Electric Stimulation; D006321:Heart / Q000187:drug effects; D006352:Heart Ventricles; D007328:Insulin / Q000494:pharmacology*; D007425:Intracellular Membranes / Q000187:drug effects; D007700:Kinetics; D008297:Male; D008565:Membrane Proteins / Q000302:isolation & purification; D008757:Methylglucosides / Q000378:metabolism*; D008970:Molecular Weight; D009004:Monosaccharide Transport Proteins / Q000302:isolation & purification / Q000378:metabolism*; D009200:Myocardial Contraction / Q000187:drug effects; D009206:Myocardium / Q000378:metabolism*; D051381:Rats; D017208:Rats, Wistar; D013347:Subcellular Fractions
D007328:Insulin; D008565:Membrane Proteins; D008757:Methylglucosides; D009004:Monosaccharide Transport Proteins; D019325:3-O-Methylglucose