Abstract
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.
Publication types
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Research Support, Non-U.S. Gov't
MeSH terms
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3-O-Methylglucose / pharmacokinetics
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Affinity Labels / metabolism
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Androstadienes / pharmacology
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Animals
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Azides / metabolism
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Biological Transport / drug effects
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Disaccharides / metabolism
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Glucose / pharmacokinetics*
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Glucose Transporter Type 4
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Glycosides
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Insulin / pharmacology
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Male
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Monosaccharide Transport Proteins / metabolism*
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Muscle Contraction / physiology*
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Muscle Proteins*
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Muscle, Skeletal / metabolism*
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Phosphatidylinositol 3-Kinases / metabolism
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Propylamines*
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Protein Serine-Threonine Kinases*
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Proto-Oncogene Proteins / physiology*
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Proto-Oncogene Proteins c-akt
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Rats
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Rats, Wistar
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Signal Transduction / physiology
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Wortmannin
Substances
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Affinity Labels
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Androstadienes
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Azides
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Disaccharides
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Glucose Transporter Type 4
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Glycosides
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Insulin
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Monosaccharide Transport Proteins
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Muscle Proteins
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Propylamines
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Proto-Oncogene Proteins
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Slc2a4 protein, rat
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2-N-(4-(1-azitrifluoroethyl)benzoyl)-1,3-bis-(mannos-4-yloxy)-2-propylamine
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3-O-Methylglucose
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Protein Serine-Threonine Kinases
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Proto-Oncogene Proteins c-akt
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Glucose
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Wortmannin