Evidence against protein kinase B as a mediator of contraction-induced glucose transport and GLUT4 translocation in rat skeletal muscle.
Both insulin and muscle contraction stimulate glucose transport activity. However, contraction stimulation does not involve the insulin signalling intermediate phosphatidylinositol 3-kinase (PI 3-kinase). Protein kinase B (PKB) has recently been identified as a direct downstream target of PI 3-kinase in the insulin signalling pathway. We have examined here whether the two stimuli share PKB as a convergent step in separate signalling pathways. Insulin stimulates both glucose transport, GLUT4 cell-surface content and PKB activity (by 4-6-fold above basal) in a wortmannin-sensitive manner in in vitro incubated rat soleus muscles. By contrast, muscle contraction, which stimulates glucose transport and the cell surface content of GLUT4 by 3-fold above basal levels, had no effect on PKB activity. These data demonstrate that PKB is not a mediator of contraction-induced glucose transport and GLUT4 translocation.
Lund
S
S
Aarhus Kommunehospital and Medical Department M (Endocrinology and Diabetes), Kommunehospitalet, Aarhus University Hospital, Denmark. sl@dadlnet.dk
Pryor
P R
PR
Ostergaard
S
S
Schmitz
O
O
Pedersen
O
O
Holman
G D
GD
D019325:3-O-Methylglucose / Q000493:pharmacokinetics; D000345:Affinity Labels / Q000378:metabolism; D000730:Androstadienes / Q000494:pharmacology; D000818:Animals; D001386:Azides / Q000378:metabolism; D001692:Biological Transport / Q000187:drug effects; D004187:Disaccharides / Q000378:metabolism; D005947:Glucose / Q000493:pharmacokinetics*; D051275:Glucose Transporter Type 4; D006027:Glycosides; D007328:Insulin / Q000494:pharmacology; D008297:Male; D009004:Monosaccharide Transport Proteins / Q000378:metabolism*; D009119:Muscle Contraction / Q000502:physiology*; D009124:Muscle Proteins; D018482:Muscle, Skeletal / Q000378:metabolism*; D019869:Phosphatidylinositol 3-Kinases / Q000378:metabolism; D011437:Propylamines; D017346:Protein Serine-Threonine Kinases; D011518:Proto-Oncogene Proteins / Q000502:physiology*; D051057:Proto-Oncogene Proteins c-akt; D051381:Rats; D017208:Rats, Wistar; D015398:Signal Transduction / Q000502:physiology; D000077191:Wortmannin
D019325:3-O-Methylglucose; D000345:Affinity Labels; D000730:Androstadienes; D001386:Azides; D004187:Disaccharides; D005947:Glucose; D051275:Glucose Transporter Type 4; D006027:Glycosides; D007328:Insulin; D009004:Monosaccharide Transport Proteins; D009124:Muscle Proteins; D019869:Phosphatidylinositol 3-Kinases; D011437:Propylamines; D017346:Protein Serine-Threonine Kinases; D011518:Proto-Oncogene Proteins; D051057:Proto-Oncogene Proteins c-akt; D000077191:Wortmannin; C495694:Slc2a4 protein, rat; C065412:2-N-(4-(1-azitrifluoroethyl)benzoyl)-1,3-bis-(mannos-4-yloxy)-2-propylamine