title: Rhodiola crenulata extract regulates hepatic glycogen and lipid metabolism via activation of the AMPK pathway.
abstract: BACKGROUND
  Metabolic syndrome may lead to many complications, such as nonalcoholic fatty liver disease (NAFLD). A natural and effective therapeutic agent for patients with NAFLD is urgently needed. In a previous study, we showed that Rhodiola crenulata root extract (RCE) regulated hepatic gluconeogenesis through activation of AMPK signaling. However, the manner in which RCE regulates hepatic lipid and glycogen metabolism remains unclear. The current study was conducted to investigate the effects of RCE on hepatic glycogen and lipid metabolism, as well as the mechanisms underlying such effects.
  
  
  METHODS
  Human hepatoma HepG2 cells were treated with RCE for 6 h under high glucose conditions, after which glycogen synthesis, lipogenesis, and relative gene expression were examined. In addition, lipogenesis-related genes were investigated in vivo.
  
  
  RESULTS
  RCE significantly increased glycogen synthesis and inhibited lipogenesis, while regulating genes related to these processes, including glycogen synthase kinase 3β (GSK3β), glycogen synthase (GS), fatty acid synthase (FAS), CCAAT/enhancer-binding protein (C/EBP), and sterol regulatory element-binding protein 1c (SREBP-1c). However, the effects caused by RCE were neutralized by compound C, an AMPK antagonist. Further studies showed that expression levels of lipogenic genes decreased at the protein and mRNA levels in the rat liver.
  
  
  CONCLUSIONS
  Our results demonstrate that RCE regulates hepatic glycogen and lipid metabolism through the AMPK signaling pathway. These results suggest that RCE is a potential intervention for patients with NAFLD.
authors.affiliation: Graduate Institute of Medical Sciences, National Defense Medical Center, Taipei, Taiwan.|Department of Radiation Oncology, Tri-Service General Hospital, National Defense Medical Center, Taipei, Taiwan.
authors.forename: Kuen-Tze
authors.initials: KT
authors.lastname: Lin
authors.affiliation: Department of Neurosurgery, Taichung Armed Forces General Hospital, Taichung, Taiwan.
authors.forename: Shih-Wei
authors.initials: SW
authors.lastname: Hsu
authors.affiliation: Graduate Institute of Aerospace and Undersea Medicine, National Defense Medical Center, Taipei, Taiwan.
authors.forename: Feng-Yi
authors.initials: FY
authors.lastname: Lai
authors.affiliation: Department of Biochemistry, National Defense Medical Center, Taipei, Taiwan.
authors.forename: Tsu-Chung
authors.initials: TC
authors.lastname: Chang
authors.affiliation: Department of Biotechnology, National Formosa University, Yunlin, Taiwan.
authors.forename: Li-Shian
authors.initials: LS
authors.lastname: Shi
authors.affiliation: Graduate Institute of Medical Sciences, National Defense Medical Center, Taipei, Taiwan. leeshihyuno1@mail.ndmctsgh.edu.tw.|Graduate Institute of Aerospace and Undersea Medicine, National Defense Medical Center, Taipei, Taiwan. leeshihyuno1@mail.ndmctsgh.edu.tw.
authors.forename: Shih-Yu
authors.initials: SY
authors.lastname: Lee
mesh_terms: D055372:AMP-Activated Protein Kinases / Q000378:metabolism*; D000818:Animals; D004365:Drugs, Chinese Herbal / Q000494:pharmacology*; D056945:Hep G2 Cells; D006801:Humans; D050356:Lipid Metabolism / Q000187:drug effects*; D008112:Liver Glycogen / Q000378:metabolism*; D020935:MAP Kinase Signaling System / Q000187:drug effects*; D065626:Non-alcoholic Fatty Liver Disease / Q000188:drug therapy; D051381:Rats; D017207:Rats, Sprague-Dawley; D029771:Rhodiola / Q000737:chemistry*
chemical_list: D004365:Drugs, Chinese Herbal; D008112:Liver Glycogen; D055372:AMP-Activated Protein Kinases
keywords: AMPK; Glycogen synthesis; Lipogenesis; Rhodiola crenulata