Insulin-stimulated translocation of the HepG2/erythrocyte-type glucose transporter expressed in 3T3-L1 adipocytes

J Biol Chem. 1989 Feb 5;264(4):2180-4.

Abstract

Insulin stimulates glucose transport into adipocytes, at least in part, via the translocation of intracellular transporters to the plasma membrane. The human HepG2-type transporter, which is not insulin-responsive in its native cell type, was expressed in 3T3-L1 adipocytes by infection with recombinant retrovirus harboring the HepG2 transporter cDNA in order to determine whether glucose transporter translocation in adipocytes is restricted to a distinct insulin-sensitive transporter species. The distributions of the endogenous murine and the HepG2 transporters were estimated by quantitative immunoblot analysis of subcellular fractions probed with either a monoclonal antibody that recognized only the human transporter or a polyclonal antibody that recognized both transporter species. In the basal state, the intracellular membrane fraction comprised approximately 50% of the total of each transporter type. Insulin decreased the content of both transporter species in the intracellular membranes by approximately 50% and increased the plasma membrane content of both species by approximately 1.5-2-fold. The similar insulin-mediated increase in the plasma membrane content of endogenous murine and HepG2 glucose transporters was verified by labeling of cell surface glycoproteins with [3H]NaBH4 followed by immunoprecipitation with glucose transporter antibodies. These data indicate that insulin-mediated translocation in 3T3-L1 adipocytes is not restricted to a tissue-specific insulin-responsive glucose transporter species and suggest that other tissue-specific factors regulate the translocation process.

Publication types

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

MeSH terms

  • Adipose Tissue / drug effects
  • Adipose Tissue / metabolism*
  • Animals
  • Carcinoma, Hepatocellular
  • Cell Differentiation
  • Cell Line
  • Cell Membrane / metabolism
  • Cells, Cultured
  • Erythrocytes / metabolism
  • Humans
  • Insulin / pharmacology*
  • Liver Neoplasms
  • Mice
  • Monosaccharide Transport Proteins / genetics
  • Monosaccharide Transport Proteins / metabolism*

Substances

  • Insulin
  • Monosaccharide Transport Proteins