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NAD(P)H oxidase participates in the palmitate-induced superoxide production and insulin secretion by rat pancreatic islets.
MedLine Citation:
PMID:  20857410     Owner:  NLM     Status:  In-Data-Review    
Abstract/OtherAbstract:
Nicotinamide adenine dinucleotide phosphate [NAD(P)H] oxidase complex has been shown to be involved in the process of glucose-stimulated insulin secretion (GSIS). In this study, we examined the effect of palmitic acid on superoxide production and insulin secretion by rat pancreatic islets and the mechanism involved. Rat pancreatic islets were incubated during 1 h with 1 mM palmitate, 1% fatty acid free-albumin, 5.6 or 10 mM glucose and in the presence of inhibitors of NAD(P)H oxidase (DPI-diphenyleneiodonium), PKC (calphostin C) and carnitine palmitoyl transferase-I (CPT-I) (etomoxir). Superoxide content was determined by hydroethidine assays. Palmitate increased superoxide production in the presence of 5.6 and 10 mM glucose. This effect was dependent on activation of PKC and NAD(P)H oxidase. Palmitic acid oxidation was demonstrated to contribute for the fatty acid induction of superoxide production in the presence of 5.6 mM glucose. In fact, palmitate caused p47(PHOX) translocation to plasma membrane, as shown by immunohistochemistry. Exposure to palmitate for 1 h up-regulated the protein content of p47(PHOX) and the mRNA levels of p22(PHOX) , gp91(PHOX) , p47(PHOX) , proinsulin and the G protein-coupled receptor 40 (GPR40). Fatty acid stimulation of insulin secretion in the presence of high glucose concentration was reduced by inhibition of NAD(P)H oxidase activity. In conclusion, NAD(P)H oxidase is an important source of superoxide in pancreatic islets and the activity of NAD(P)H oxidase is involved in the control of insulin secretion by palmitate. J. Cell. Physiol. 226: 1110-1117, 2011. © 2010 Wiley-Liss, Inc.
Authors:
Maria Fernanda R Graciano; Laila R B Santos; Rui Curi; Angelo R Carpinelli
Publication Detail:
Type:  Journal Article    
Journal Detail:
Title:  Journal of cellular physiology     Volume:  226     ISSN:  1097-4652     ISO Abbreviation:  J. Cell. Physiol.     Publication Date:  2011 Apr 
Date Detail:
Created Date:  2011-01-26     Completed Date:  -     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  0050222     Medline TA:  J Cell Physiol     Country:  United States    
Other Details:
Languages:  eng     Pagination:  1110-7     Citation Subset:  IM    
Copyright Information:
Copyright © 2010 Wiley-Liss, Inc.
Affiliation:
Department of Physiology and Biophysics, Institute of Biomedical Sciences, University of São Paulo (USP), São Paulo, SP, Brazil. mafe@icb.usp.br.
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