Chronic ethanol feeding impairs endothelin-1-stimulated glucose uptake via decreased G alpha 11 expression in rat adipocytes

Am J Physiol Endocrinol Metab. 2003 Aug;285(2):E303-10. doi: 10.1152/ajpendo.00547.2002. Epub 2003 Apr 8.

Abstract

Chronic ethanol feeding decreases insulin-stimulated glucose uptake in rat adipocytes. Here, we show that chronic ethanol also decreases endothelin-stimulated glucose uptake. Endothelin-1 increased uptake of 2-deoxyglucose 2.4-fold in adipocytes isolated from pair-fed rats. However, in adipocytes isolated from rats that had consumed a diet containing 35% ethanol for 4 wk, endothelin-1 did not increase glucose uptake. Although endothelin-1 increased GLUT4 quantity at the plasma membrane in adipocytes from pair-fed rats, there was no increase in GLUT4 after chronic ethanol feeding. Loss of endothelin-1-stimulated glucose uptake after ethanol feeding was associated with a specific decrease in the quantity of Galpha11 in plasma membranes, with no change in Galphaq quantity. Activation of proline-rich tyrosine kinase 2 (PYK2), a downstream target of Galphaq/11 that is required for endothelin-1-stimulated GLUT4 translocation in 3T3-L1 adipocytes, was also suppressed after chronic ethanol feeding. In contrast, activation of p38 MAPK by endothelin-1 was not affected by chronic ethanol exposure. These data demonstrate that chronic ethanol feeding suppresses endothelin-1-stimulated glucose uptake and suggest that decreased expression of Galpha11 coupled to impaired endothelin-1-dependent activation of PYK2 contributes to this response.

Publication types

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

MeSH terms

  • Adipocytes / metabolism*
  • Adipocytes / ultrastructure
  • Animals
  • Cell Membrane / chemistry
  • Deoxyglucose / metabolism
  • Endothelin-1 / pharmacology*
  • Enzyme Activation / drug effects
  • Ethanol / administration & dosage*
  • Focal Adhesion Kinase 2
  • GTP-Binding Protein alpha Subunits, Gq-G11
  • Glucose / metabolism*
  • Glucose Transporter Type 1
  • Glucose Transporter Type 4
  • Heterotrimeric GTP-Binding Proteins / analysis*
  • Male
  • Mitogen-Activated Protein Kinases / metabolism
  • Monosaccharide Transport Proteins / analysis
  • Muscle Proteins*
  • Protein-Tyrosine Kinases / metabolism
  • Rats
  • Rats, Wistar
  • p38 Mitogen-Activated Protein Kinases

Substances

  • Endothelin-1
  • Glucose Transporter Type 1
  • Glucose Transporter Type 4
  • Monosaccharide Transport Proteins
  • Muscle Proteins
  • Slc2a4 protein, rat
  • Ethanol
  • Deoxyglucose
  • Protein-Tyrosine Kinases
  • Focal Adhesion Kinase 2
  • Ptk2b protein, rat
  • Mitogen-Activated Protein Kinases
  • p38 Mitogen-Activated Protein Kinases
  • GTP-Binding Protein alpha Subunits, Gq-G11
  • Heterotrimeric GTP-Binding Proteins
  • Glucose