Leucine promotes glucose uptake in skeletal muscles of rats

Biochem Biophys Res Commun. 2002 Dec 20;299(5):693-6. doi: 10.1016/s0006-291x(02)02717-1.

Abstract

Soleus muscles isolated from normal rats were incubated to evaluate whether or not leucine promotes glucose uptake under insulin-free conditions, using a labeled 2-deoxyglucose uptake assay. Glucose uptake was promoted by 2mM leucine. A metabolite of leucine, alpha-ketoisocaproic acid (alpha-KIC), also exhibited a similar stimulatory effect, although this was not as potent as leucine. Stimulation of glucose uptake by leucine was completely canceled by pre-treatment with either 10 microM LY294002, a specific inhibitor of phosphatidylinositol 3-kinase (PI3-kinase), or 6 microM GF109203X, a specific inhibitor of protein kinase C (PKC). No significant change was observed by pre-treatment with 1 microM rapamycin, a specific inhibitor of mammalian target of rapamycin (mTOR). These results suggest that leucine stimulates glucose transport in skeletal muscle via PI3-kinase and PKC pathways independently of the mammalian target of mTOR. They also suggest that leucine stimulates glucose transport by an insulin-independent mechanism.

MeSH terms

  • Animals
  • Biological Transport
  • Culture Techniques
  • Dose-Response Relationship, Drug
  • Enzyme Inhibitors / pharmacology
  • Glucose / metabolism*
  • Insulin / pharmacology
  • Keto Acids / pharmacology
  • Leucine / pharmacology*
  • Male
  • Models, Biological
  • Muscle, Skeletal / drug effects
  • Muscle, Skeletal / metabolism*
  • Rats
  • Rats, Sprague-Dawley

Substances

  • Enzyme Inhibitors
  • Insulin
  • Keto Acids
  • alpha-ketoisocaproic acid
  • Leucine
  • Glucose