Decreased insulin-stimulated GLUT-4 translocation in glycogen-supercompensated muscles of exercised rats

Am J Physiol. 1999 May;276(5):E907-12. doi: 10.1152/ajpendo.1999.276.5.E907.

Abstract

It was recently found that the effect of an exercise-induced increase in muscle GLUT-4 on insulin-stimulated glucose transport is masked by a decreased responsiveness to insulin in glycogen-supercompensated muscle. We evaluated the role of hexosamines in this decrease in insulin responsiveness and found that UDP-N-acetyl hexosamine concentrations were not higher in glycogen-supercompensated muscles than in control muscles with a low glycogen content. We determined whether the smaller increase in glucose transport is due to translocation of fewer GLUT-4 to the cell surface with the 2-N-4-(1-azi-2,2,2-trifluroethyl)-benzoyl-1, 3-bis(D-mannose-4-yloxy)-2-propylamine (ATB-[2-3H]BMPA) photolabeling technique. The insulin-induced increase in GLUT-4 at the cell surface was no greater in glycogen-supercompensated exercised muscle than in muscles of sedentary controls and only 50% as great as in exercised muscles with a low glycogen content. We conclude that the decreased insulin responsiveness of glucose transport in glycogen-supercompensated muscle is not due to increased accumulation of hexosamine biosynthetic pathway end products and that the smaller increase in glucose transport is mediated by translocation of fewer GLUT-4 to the cell surface.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Animals
  • Biological Transport
  • Cell Membrane / metabolism
  • Glucose / metabolism
  • Glucose Transporter Type 4
  • Glycogen / metabolism*
  • Hexosamines / metabolism
  • Hexoses / metabolism
  • Insulin / pharmacology*
  • Monosaccharide Transport Proteins / metabolism*
  • Muscle Proteins*
  • Muscle, Skeletal / drug effects
  • Muscle, Skeletal / metabolism*
  • Physical Exertion / physiology*
  • Rats
  • Rats, Wistar
  • Uridine Diphosphate / metabolism
  • beta-Alanine / analogs & derivatives
  • beta-Alanine / metabolism

Substances

  • Glucose Transporter Type 4
  • Hexosamines
  • Hexoses
  • Insulin
  • Monosaccharide Transport Proteins
  • Muscle Proteins
  • Slc2a4 protein, rat
  • beta-Alanine
  • 2,2-dimethyl-beta-alanine
  • Uridine Diphosphate
  • Glycogen
  • Glucose