Pu-erh tea hot-water extract activates Akt and induces insulin-independent glucose transport in rat skeletal muscle

J Med Food. 2013 Mar;16(3):259-62. doi: 10.1089/jmf.2012.2520. Epub 2013 Feb 25.

Abstract

Skeletal muscle is a major organ that is important for whole-body glucose metabolism. We found that when isolated rat epitrochlearis muscle was incubated with a Pu-erh tea hot-water extract (PTE) for 30 min, the rate of 3-O-methyl-D-glucose (3MG) transport increased in the absence of insulin. This activation was associated with an increase in Ser(473) phosphorylation of Akt, a signaling intermediary leading to insulin-dependent glucose transport, but not Tyr(458) phosphorylation of phosphoinositide 3-kinase p85, an upstream molecule of Akt. PTE-stimulated 3MG transport was also not accompanied by Thr(172) phosphorylation of the catalytic α-subunit of 5'-AMP-activated protein kinase (AMPK). Gallic acid, a water-soluble ingredient in Pu-erh tea, stimulated Akt phosphorylation, but not AMPK phosphorylation. These results suggest that Pu-erh tea potentially promotes skeletal muscle glucose transport at least in part by activating Akt.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • AMP-Activated Protein Kinases / metabolism
  • Amino Acids / metabolism
  • Animals
  • Biological Transport
  • Camellia / chemistry*
  • Gallic Acid / pharmacology*
  • Glucose / metabolism*
  • Insulin / metabolism*
  • Muscle, Skeletal / drug effects*
  • Muscle, Skeletal / metabolism
  • Phosphatidylinositol 3-Kinases / metabolism
  • Phosphorylation
  • Plant Extracts / pharmacology*
  • Plant Leaves
  • Protein Subunits / metabolism
  • Proto-Oncogene Proteins c-akt / metabolism*
  • Rats
  • Signal Transduction
  • Tea

Substances

  • Amino Acids
  • Insulin
  • Plant Extracts
  • Protein Subunits
  • Tea
  • Gallic Acid
  • Phosphatidylinositol 3-Kinases
  • Proto-Oncogene Proteins c-akt
  • AMP-Activated Protein Kinases
  • Glucose