An energetic tale of AMPK-independent effects of metformin.
Metformin has become a mainstay in the modest therapeutic armamentarium for the treatment of the insulin resistance of type 2 diabetes mellitus. Although metformin functions primarily by reducing hepatic glucose output, the molecular mechanism mediating this effect had remained elusive until recently. Metformin impairs ATP production, activating the conserved sensor of nutritional stress AMP-activated protein kinase (AMPK), thus providing a plausible and generally accepted model for suppression of gluconeogenic gene expression and glucose output. In this issue of the JCI, Foretz et al. refute this hypothesis by showing that AMPK is dispensable for the effects of metformin on hepatic glucose output in primary hepatocytes; rather, their data suggest that the antidiabetic effects of metformin in the liver are mediated directly by reducing energy charge.
Miller
Russell A
RA
The Institute for Diabetes, Obesity, and Metabolism, University of Pennsylvania, Philadelphia, Pennsylvania, USA.
Birnbaum
Morris J
MJ
D055372:AMP-Activated Protein Kinases; D050260:Carbohydrate Metabolism; D003924:Diabetes Mellitus, Type 2 / Q000188:drug therapy / Q000378:metabolism; D015870:Gene Expression / Q000187:drug effects; D022781:Hepatocytes / Q000187:drug effects / Q000378:metabolism; D006801:Humans; D007004:Hypoglycemic Agents / Q000378:metabolism / Q000494:pharmacology / Q000627:therapeutic use; D007333:Insulin Resistance; D008099:Liver / Q000187:drug effects / Q000378:metabolism; D008687:Metformin / Q000378:metabolism / Q000494:pharmacology / Q000627:therapeutic use; D011494:Protein Kinases / Q000378:metabolism / Q000494:pharmacology; D015398:Signal Transduction / Q000187:drug effects
D007004:Hypoglycemic Agents; D008687:Metformin; D011494:Protein Kinases; D055372:AMP-Activated Protein Kinases