Insulin regulation of the two glucose transporters in 3T3-L1 adipocytes

J Biol Chem. 1990 Aug 15;265(23):13801-8.

Abstract

The amounts of the brain type and muscle type glucose transporters (designated Glut 1 and 4, respectively) in 3T3-L1 adipocytes have been determined by quantitative immunoblotting with antibodies against their carboxyl-terminal peptides. There are about 950,000 and 280,000 copies of Glut 1 and 4, respectively, per cell. Insulin caused the translocation of both types of transporters from an intracellular location to the plasma membrane. The insulin-elicited increase in cell surface transporters was assessed by labeling the surface transporters with a newly developed, membrane-impermeant, photoaffinity labeling reagent for glucose transporters. The increases in Glut 1 and 4 averaged 6.5- and 17-fold, respectively, whereas there was a 21-fold in hexose transport. These results indicate that the translocation of Glut 4 could largely account for the insulin effect on transport rate, but only if the intrinsic activity of Glut 4 is much higher than that of Glut 1. The two transporters are colocalized intracellularly: vesicles (average diameter 72 nm) isolated from the intracellular membranes by immunoadsorption with antibodies against Glut 1 contained 95% of the Glut 4 and, conversely, vesicles isolated with antibodies against Glut 4 contained 85% of the Glut 1.

Publication types

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

MeSH terms

  • Adipose Tissue / cytology
  • Adipose Tissue / drug effects
  • Adipose Tissue / metabolism*
  • Affinity Labels / metabolism
  • Animals
  • Cell Differentiation
  • Cell Membrane / metabolism
  • Cells, Cultured
  • Cytoplasmic Granules / metabolism
  • Cytoplasmic Granules / ultrastructure
  • Deoxy Sugars / metabolism*
  • Deoxyglucose / metabolism*
  • Insulin / pharmacology*
  • Intracellular Membranes / metabolism*
  • Kinetics
  • Mice
  • Microscopy, Electron
  • Molecular Weight
  • Monosaccharide Transport Proteins / isolation & purification
  • Monosaccharide Transport Proteins / metabolism*

Substances

  • Affinity Labels
  • Deoxy Sugars
  • Insulin
  • Monosaccharide Transport Proteins
  • Deoxyglucose