p-Synephrine stimulates glucose consumption via AMPK in L6 skeletal muscle cells.

Abstract

Interest in p-synephrine, the primary protoalkaloid in the extract of bitter orange and other citrus species, has increased due to its various pharmacological effects and related adverse effects. The lipolytic activity of p-synephrine has been repeatedly revealed by in vitro and in vivo studies and p-synephrine is currently marketed as a dietary supplement for weight loss. The present study investigated the effect of p-synephrine on glucose consumption and its action mechanism in L6 skeletal muscle cells. Treatment of L6 skeletal muscle cells with p-synephrine (0-100μM) did not affect cell viability and increased basal glucose consumption up to 50% over the control in a dose-dependent manner. The basal- or insulin-stimulated lactic acid production as well as glucose consumption was significantly increased by the addition of p-synephrine. p-Synephrine stimulated the phosphorylation of AMPK but not of Akt. p-Synephrine-induced glucose consumption was sensitive to the inhibition of AMPK but not to the inhibition of PI3 kinase. p-Synephrine also stimulated the translocation of Glut4 from the cytoplasm to the plasma membrane; this stimulation was suppressed by the inhibition of AMPK, but not of PI3 kinase. Taken together, p-synephrine can stimulate glucose consumption (Glut4-dependent glucose uptake) by stimulating AMPK activity, regardless of insulin-stimulated PI3 kinase-Akt activity in L6 skeletal muscle cells.

• Authors: Na-Young Hong, Zhi-Gang Cui, Hee-Kyoung Kang, Dae-Ho Lee, Young-Ki Lee, Deok-Bae Park
• Journal: Biochemical and biophysical research communications (Biochem Biophys Res Commun) Vol. 418 Issue 4 Pg. 720-4 (Feb 24 2012) ISSN: 1090-2104 [Electronic] United States
• PMID: 22306011 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)
• Copyright: Copyright © 2012 Elsevier Inc. All rights reserved.

Chemical References

• Adrenergic alpha-Agonists
• AMP-Activated Protein Kinases
• Glucose
• Synephrine

Topics

• AMP-Activated Protein Kinases (metabolism)
• Adrenergic alpha-Agonists (pharmacology)
• Animals
• Cell Line
• Glucose (metabolism)
• Humans
• Muscle, Skeletal (drug effects, enzymology)
• Rats
• Synephrine (pharmacology)