Document Detail


Palmitate activates insulin signaling pathway in pancreatic rat islets.
MedLine Citation:
PMID:  19287336     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
OBJECTIVE: To investigate the action of palmitate on insulin receptor (IR) signaling pathway in rat pancreatic islets. The following proteins were studied: IR substrate-1 and -2 (IRS1 and IRS2), phosphatidylinositol 3-kinase, extracellular signal-regulated protein kinase-1 and -2 (ERK1/2), and signal transducer and activator of transcription 3 (STAT3). METHODS: Immunoblotting and immunoprecipitation assays were used to evaluate the phosphorylation states of IRS1 and IRS2 (tyrosine [Tyr]), ERK1/2 (threonine 202 [Thr202]/Tyr204), and STAT3 (serine [Ser727]). RESULTS: The exposure of rat pancreatic islets to 0.1-mmol/L palmitate for up to 30 minutes produced a significant increase of Tyr phosphorylation in IRS2 but not in IRS1. The association of phosphatidylinositol 3-kinase with IRS2 was also upregulated by palmitate. Exposure to 5.6-mmol/L glucose caused a gradual decrease in ERK1/2 (Thr202/Tyr204) and STAT3 (serine [Ser727]) phosphorylations after 30-minute incubation. The addition of palmitate (0.1 mmol/L), associated with 5.6-mmol/L glucose, abolished these latter effects of glucose after 15-minute incubation. CONCLUSIONS: Palmitate at physiological concentration associated with 5.6-mmol/L glucose activates IR signaling pathway in pancreatic beta cells.
Authors:
Maria Fernanda R Graciano; Tatiane C A Nogueira; Carla R O Carvalho; Rui Curi; Angelo R Carpinelli
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Publication Detail:
Type:  In Vitro; Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  Pancreas     Volume:  38     ISSN:  1536-4828     ISO Abbreviation:  Pancreas     Publication Date:  2009 Jul 
Date Detail:
Created Date:  2009-06-25     Completed Date:  2009-09-25     Revised Date:  2009-11-19    
Medline Journal Info:
Nlm Unique ID:  8608542     Medline TA:  Pancreas     Country:  United States    
Other Details:
Languages:  eng     Pagination:  578-84     Citation Subset:  IM    
Affiliation:
Department of Physiology and Biophysics, Institute of Biomedical Sciences, University of São Paulo, São Paulo, Brazil. mafe@icb.usp.br
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MeSH Terms
Descriptor/Qualifier:
1-Phosphatidylinositol 3-Kinase / metabolism
Animals
Caspase 3 / metabolism
Cell Line
Female
Glucose / pharmacology
Immunoblotting
Immunoprecipitation
Insulin Receptor Substrate Proteins / metabolism
Islets of Langerhans / drug effects*,  metabolism
Macrophages / cytology,  drug effects,  enzymology
Mitogen-Activated Protein Kinase 1 / metabolism
Mitogen-Activated Protein Kinase 3 / metabolism
Palmitates / pharmacology*
Phosphorylation / drug effects
Rats
Receptor, Insulin / metabolism*
STAT3 Transcription Factor / metabolism
Signal Transduction / drug effects*
Time Factors
Chemical
Reg. No./Substance:
0/Insulin Receptor Substrate Proteins; 0/Irs1 protein, rat; 0/Irs2 protein, rat; 0/Palmitates; 0/STAT3 Transcription Factor; 0/Stat3 protein, rat; 50-99-7/Glucose; EC 2.7.1.137/1-Phosphatidylinositol 3-Kinase; EC 2.7.10.1/Receptor, Insulin; EC 2.7.11.24/Mitogen-Activated Protein Kinase 1; EC 2.7.11.24/Mitogen-Activated Protein Kinase 3; EC 3.4.22.-/Caspase 3

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


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