Document Detail


Resistin induces insulin resistance by both AMPK-dependent and AMPK-independent mechanisms in HepG2 cells.
MedLine Citation:
PMID:  19440859     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
Resistin is a 12.5-KDa cysteine-rich peptide that has been implicated in the impairment of glucose homeostasis via the AMP-activated protein kinase (AMPK) pathway in a rodent model. However, the role resistin plays in humans is controversial. This study investigated the effect of resistin on glucose metabolism and insulin signaling using human recombinant resistin and small interfering RNA (siRNA) against AMPKalpha2 to treat the human liver HepG2 cells. The mRNA of key genes involved in glucose metabolism and the insulin-signaling pathway were detected by real-time RT-PCR. Phosphorylation levels of Akt and AMPK were measured by western blot. The incorporation of D-[U-(14)C] glucose into glycogen was quantitated by liquid scintillation counting. The results demonstrate that resistin stimulated expressions of glucose-6-phosphatase (G6Pase), phosphoenolypyruvate carboxykinase (PEPCK), and suppressor of cytokine signaling 3 (SOCS-3), repressed the expressions of insulin receptor substrate 2(IRS-2) and glucose transporter 2(GLUT2). In addition, resistin inhibited the insulin-induced phosphorylation of Akt independent of AMPK. In conclusion, our findings suggest that resistin induces insulin resistance in HepG2 cells at least partly via induction of SOCS-3 expression and reduction of Akt phosphorylation through an AMPK-independent mechanism. Resistin also increases glucose production via AMPK-mediated upregulated expression of the genes encoding hepatic gluconeogenic enzymes, G6Pase, and PEPCK.
Authors:
Zhaofan Luo; Ying Zhang; Fangping Li; Juan He; Helin Ding; Li Yan; Hua Cheng
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't     Date:  2009-05-08
Journal Detail:
Title:  Endocrine     Volume:  36     ISSN:  1355-008X     ISO Abbreviation:  Endocrine     Publication Date:  2009 Aug 
Date Detail:
Created Date:  2009-07-07     Completed Date:  2009-10-01     Revised Date:  2010-06-24    
Medline Journal Info:
Nlm Unique ID:  9434444     Medline TA:  Endocrine     Country:  United States    
Other Details:
Languages:  eng     Pagination:  60-9     Citation Subset:  IM    
Affiliation:
Department of Endocrinology, The Second Affiliated Hospital, Sun Yat-Sen University, 510120, Guangzhou, People's Republic of China.
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MeSH Terms
Descriptor/Qualifier:
AMP-Activated Protein Kinases / genetics,  metabolism*
Carcinoma, Hepatocellular / metabolism*,  pathology
Cell Line, Tumor
Gene Expression / drug effects,  physiology
Glucaric Acid / metabolism
Glucose Transporter Type 2 / genetics
Glucose-6-Phosphatase / genetics
Glycogen / biosynthesis
Humans
Hypoglycemic Agents / metabolism,  pharmacology
Insulin / metabolism,  pharmacology
Insulin Receptor Substrate Proteins / genetics
Insulin Resistance / physiology
Liver Neoplasms / metabolism*,  pathology
Phosphoenolpyruvate Carboxykinase (GTP) / genetics
Phosphorylation / drug effects,  physiology
Proto-Oncogene Proteins c-akt / metabolism
RNA, Small Interfering
Resistin / metabolism*,  pharmacology
Signal Transduction / drug effects,  physiology
Suppressor of Cytokine Signaling Proteins / genetics
Chemical
Reg. No./Substance:
0/Glucose Transporter Type 2; 0/Hypoglycemic Agents; 0/IRS2 protein, human; 0/Insulin Receptor Substrate Proteins; 0/RETN protein, human; 0/RNA, Small Interfering; 0/Resistin; 0/SLC2A2 protein, human; 0/SOCS3 protein, human; 0/Suppressor of Cytokine Signaling Proteins; 11061-68-0/Insulin; 25525-21-7/Glucaric Acid; 9005-79-2/Glycogen; EC 2.7.11.1/AMP-Activated Protein Kinases; EC 2.7.11.1/PRKAA2 protein, human; EC 2.7.11.1/Proto-Oncogene Proteins c-akt; EC 3.1.3.9/Glucose-6-Phosphatase; EC 4.1.1.32/Phosphoenolpyruvate Carboxykinase (GTP)

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine


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