title: Increased skeletal muscle glucose uptake by rosemary extract through AMPK activation.
abstract: Stimulation of the energy sensor AMP-activated kinase (AMPK) has been viewed as a targeted approach to increase glucose uptake by skeletal muscle and control blood glucose homeostasis. Rosemary extract (RE) has been reported to activate AMPK in hepatocytes and reduce blood glucose levels in vivo but its effects on skeletal muscle are not known. In the present study, we examined the effects of RE and the mechanism of regulation of glucose uptake in muscle cells. RE stimulated glucose uptake in L6 myotubes in a dose- and time-dependent manner. Maximum stimulation was seen with 5 μg/mL of RE for 4 h (184% ± 5.07% of control, p < 0.001), a response comparable to maximum insulin (207% ± 5.26%, p < 0.001) and metformin (216% ± 8.77%, p < 0.001) stimulation. RE did not affect insulin receptor substrate 1 and Akt phosphorylation but significantly increased AMPK and acetyl-CoA carboxylase phosphorylation. Furthermore, the RE-stimulated glucose uptake was significantly reduced by the AMPK inhibitor compound C, but remained unchanged by the PI3K inhibitor, wortmannin. RE did not affect GLUT4 or GLUT1 glucose transporter translocation in contrast with a significant translocation of both transporters seen with insulin or metformin treatment. Our study is the first to show a direct effect of RE on muscle cell glucose uptake by a mechanism that involves AMPK activation.
authors: Department of Health Sciences, Brock University, St. Catharines, ON L2S 3A1, Canada.
authors: Madina
authors: M
authors: Naimi
authors: Theodoros
authors: T
authors: Tsakiridis
authors: Theocharis C
authors: TC
authors: Stamatatos
authors: Dimitris I
authors: DI
authors: Alexandropoulos
authors: Evangelia
authors: E
authors: Tsiani
mesh_terms: D055372:AMP-Activated Protein Kinases / Q000235:genetics / Q000378:metabolism*; D000103:Acetyl-CoA Carboxylase / Q000235:genetics / Q000378:metabolism; D000818:Animals; D050260:Carbohydrate Metabolism / Q000187:drug effects*; D002478:Cells, Cultured; D005947:Glucose / Q000378:metabolism*; D051272:Glucose Transporter Type 1 / Q000235:genetics / Q000378:metabolism; D051275:Glucose Transporter Type 4 / Q000235:genetics / Q000378:metabolism; D022781:Hepatocytes / Q000187:drug effects / Q000378:metabolism; D007004:Hypoglycemic Agents / Q000494:pharmacology; D007328:Insulin / Q000378:metabolism; D055504:Insulin Receptor Substrate Proteins / Q000235:genetics / Q000378:metabolism; D018485:Muscle Fibers, Skeletal / Q000187:drug effects / Q000378:metabolism; D018482:Muscle, Skeletal / Q000187:drug effects* / Q000378:metabolism; D010766:Phosphorylation; D010936:Plant Extracts / Q000494:pharmacology*; D051057:Proto-Oncogene Proteins c-akt / Q000235:genetics / Q000378:metabolism; D051381:Rats; D027542:Rosmarinus / Q000737:chemistry*
chemical_list: D051272:Glucose Transporter Type 1; D051275:Glucose Transporter Type 4; D007004:Hypoglycemic Agents; D007328:Insulin; D055504:Insulin Receptor Substrate Proteins; C526296:Irs1 protein, rat; D010936:Plant Extracts; C495679:Slc2a1 protein, rat; C495694:Slc2a4 protein, rat; D051057:Proto-Oncogene Proteins c-akt; D055372:AMP-Activated Protein Kinases; D000103:Acetyl-CoA Carboxylase; D005947:Glucose
keywords: cellules musculaires; energy regulation; insulin resistance; insulinorésistance; metabolism; muscle cells; métabolisme; nutrition; régulation énergétique