Document Detail


Disruption of glucose homeostasis and induction of insulin resistance by elevated free fatty acids in human L02 hepatocytes.
MedLine Citation:
PMID:  19494713     Owner:  NLM     Status:  In-Process    
Abstract/OtherAbstract:
Free fatty acids (FFA) have been implicated as an important causative link between obesity, insulin resistance, and Type 2 diabetes. However, the underlying mechanisms especially for FFA-mediated hepatic insulin resistance are not fully elucidated. Here, we investigated the impaired sites in insulin signaling pathways and mechanisms of insulin resistance induced by elevated FFA in L02 hepatocytes. L02 cells were cultured in Dulbecco's modified eagle medium containing various concentrations of palmitic acid (PA) for 24 h followed by 10(-7) mol/l insulin stimulation. In some experiments, cells were pre-treated with enzymatic inhibitor Wortmannin (10(-6) mol/l). Glucose levels in medium, cytosolic glycogen contents, and phosphoenolpyruvate carboxykinase (PEPCK) activity were measured. Protein level of insulin receptor substrate (IRS)-2 and phosphorylated Akt were detected by Western blot analysis. L02 cells treated with high levels of PA exhibited increased glucose levels, whereas hepatic glycogen contents were decreased in a dose-dependent manner as compared to the control cells. There was a significant attenuation of IRS- 2 protein expression in the cells cultured with PA, and Wortmannin intervention exhibited different IRS-2 protein level with or without PA treatment. In accordance with the reduced IRS-2 level, the insulin-stimulated phosphorylation of Akt was diminished in the PA-treated cells. Basal PEPCK activity and insulin- regulated PEPCK activity were overstimulated in the cells incubated with PA. These data indicate high levels of FFA can disrupt glucose homeostasis, inflict some defects in insulin signaling, and induce insulin resistance in L02 cells.
Authors:
X-D Wan; W-B Yang; Y-Z Xia; J-F Wang; T Lu; X-M Wang
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't     Date:  2009-04-29
Journal Detail:
Title:  Journal of endocrinological investigation     Volume:  32     ISSN:  1720-8386     ISO Abbreviation:  J. Endocrinol. Invest.     Publication Date:  2009 May 
Date Detail:
Created Date:  2009-10-01     Completed Date:  -     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  7806594     Medline TA:  J Endocrinol Invest     Country:  Italy    
Other Details:
Languages:  eng     Pagination:  454-9     Citation Subset:  IM    
Affiliation:
Department of Biochemistry and Molecular Biology, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, P. R. China.
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