A high-fructose diet impairs Akt and PKCzeta phosphorylation and GLUT4 translocation in rat skeletal muscle

Horm Metab Res. 2008 Aug;40(8):528-32. doi: 10.1055/s-2008-1073162. Epub 2008 May 21.

Abstract

The molecular mechanism of insulin resistance induced by high-fructose feeding is not fully understood. The present study investigated the role of downstream signaling molecules of phosphatidylinositol 3-kinase (PI3K) in the insulin-stimulated skeletal muscle of high-fructose-fed rats. Rats were divided into chow-fed and fructose-fed groups. The results of the euglycemic clamp study (insulin infusion rates: 6 mU/kg BW/min) showed a significant decrease in the glucose infusion rate (GIR) and the metabolic clearance rate of glucose (MCR) in fructose-fed rats compared with chow-fed rats. In skeletal muscle removed immediately after the clamp procedure, high-fructose feeding did not alter protein levels of protein kinase B (PKB/Akt), protein kinase C zeta (PKCzeta), or glucose transporter 4 (GLUT4). However, insulin-stimulated phosphorylation of Akt and PKCzeta and GLUT4 translocation to the plasma membrane were reduced. Our findings suggest that insulin resistance in fructose-fed rats is associated with impaired Akt and PKCzeta activation and GLUT4 translocation in skeletal muscle.

MeSH terms

  • Animals
  • Blood Glucose / metabolism
  • Blotting, Western
  • Diet / adverse effects*
  • Fructose / adverse effects*
  • Glucose Clamp Technique
  • Glucose Transporter Type 4 / metabolism*
  • Insulin / physiology
  • Male
  • Muscle, Skeletal / enzymology
  • Muscle, Skeletal / metabolism
  • Oncogene Protein v-akt / metabolism*
  • Phosphorylation
  • Protein Kinase C / metabolism*
  • Protein Transport / physiology
  • Rats
  • Rats, Wistar
  • Signal Transduction / drug effects
  • Signal Transduction / physiology

Substances

  • Blood Glucose
  • Glucose Transporter Type 4
  • Insulin
  • Slc2a4 protein, rat
  • Fructose
  • Oncogene Protein v-akt
  • protein kinase C zeta
  • Protein Kinase C