title: Azuki bean (Vigna angularis) extract stimulates the phosphorylation of AMP-activated protein kinase in HepG2 cells and diabetic rat liver.
abstract: BACKGROUND
  The activation of AMP-activated protein kinase (AMPK) has a beneficial effect on hyperglycaemia. The aim of this study was to examine whether an azuki bean (Vigna angularis) extract (ABE) stimulates the AMPK or insulin signalling pathways in a liver cell line in response to hyperglycaemia, as well as in a diabetic rat liver.
  
  
  RESULTS
  HepG2 cells were incubated with 5 or 20 mmol L(-1) glucose and then treated with ABE. Streptozotocin-induced diabetic rats received 0, 10, or 40 mg kg(-1) ABE orally. Blood chemistry and phosphorylation of AMPK and Akt (a serine/threonine kinase) in the livers were examined. There was a significant increase in the levels of AMPK and Akt phosphorylation in ABE-treated HepG2 cells. AMPK phosphorylation increased significantly in glucose-stimulated HepG2 cells that were treated with ABE. In the 40 mg kg(-1) ABE-treated diabetic rats, the glucose levels were lower than in the control. Phosphorylation of AMPK in ABE-untreated diabetic rat livers decreased significantly. Conversely, ABE treatment increased the phosphorylation of AMPK and Akt in the diabetic rat liver.
  
  
  CONCLUSIONS
  ABE treatment upregulated AMPK phosphorylation in HepG2 cells, and upregulated AMPK and Akt phosphorylation in the diabetic rat liver. These data suggest that ABE can potentially improve glucose intolerance.
authors.affiliation: Department of Nutrition, Aomori University of Health and Welfare, Aomori, 030-8505, Japan.
authors.forename: Shin
authors.initials: S
authors.lastname: Sato
authors.affiliation: School of Nutrition and Dietetics, Faculty of Health and Social Work, Kanagawa University of Human Services, Kanagawa, 238-8522, Japan.
authors.forename: Yuuka
authors.initials: Y
authors.lastname: Mukai
authors.affiliation: Department of Nutrition, Aomori University of Health and Welfare, Aomori, 030-8505, Japan.
authors.forename: Saori
authors.initials: S
authors.lastname: Kataoka
authors.affiliation: Graduate School of Environmental Science, Hokkaido University, Sapporo, 060-0810, Japan.
authors.forename: Masaaki
authors.initials: M
authors.lastname: Kurasaki
mesh_terms: D055372:AMP-Activated Protein Kinases / Q000235:genetics / Q000378:metabolism*; D000818:Animals; D003921:Diabetes Mellitus, Experimental / Q000378:metabolism*; D004305:Dose-Response Relationship, Drug; D005786:Gene Expression Regulation / Q000187:drug effects; D005947:Glucose / Q000494:pharmacology; D056945:Hep G2 Cells; D022781:Hepatocytes / Q000187:drug effects; D006801:Humans; D008099:Liver / Q000187:drug effects* / Q000378:metabolism; D010766:Phosphorylation; D010936:Plant Extracts / Q000008:administration & dosage / Q000737:chemistry / Q000494:pharmacology*; D051057:Proto-Oncogene Proteins c-akt / Q000235:genetics / Q000378:metabolism; D051381:Rats; D015398:Signal Transduction; D000070658:Vigna / Q000737:chemistry*
chemical_list: D010936:Plant Extracts; D051057:Proto-Oncogene Proteins c-akt; D055372:AMP-Activated Protein Kinases; D005947:Glucose
keywords: Akt; HepG2 cells; adenosine monophosphate-activated protein kinase; azuki bean; diabetes; liver