title: Identification of intracellular peptides in rat adipose tissue: Insights into insulin resistance.
abstract: Intracellular peptides generated by the proteasome and oligopeptidases have been suggested to function in signal transduction and to improve insulin resistance in mice fed a high-caloric diet. The aim of this study was to identify specific intracellular peptides in the adipose tissue of Wistar rats that could be associated with the physiological and therapeutic control of glucose uptake. Using semiquantitative mass spectrometry and LC/MS/MS analyses, we identified ten peptides in the epididymal adipose tissue of the Wistar rats; three of these peptides were present at increased levels in rats that were fed a high-caloric Western diet (WD) compared with rats fed a control diet (CD). The results of affinity chromatography suggested that in the cytoplasm of epididymal adipose tissue from either WD or CD rats, distinctive proteins bind to these peptides. However, despite the observed increase in the WD animals, the evaluated peptides increased insulin-stimulated glucose uptake in 3T3-L1 adipocytes treated with palmitate. Thus, intracellular peptides from the adipose tissue of Wistar rats can bind to specific proteins and facilitate insulin-induced glucose uptake in 3T3-L1 adipocytes.
authors: Department of Cell Biology and Development, University of São Paulo, São Paulo, Brazil.
authors: Denise A
authors: DA
authors: Berti
authors: Lilian C
authors: LC
authors: Russo
authors: Leandro M
authors: LM
authors: Castro
authors: Lilian
authors: L
authors: Cruz
authors: Fábio C
authors: FC
authors: Gozzo
authors: Joel C
authors: JC
authors: Heimann
authors: Fabio B
authors: FB
authors: Lima
authors: Ariclécio C
authors: AC
authors: Oliveira
authors: Sandra
authors: S
authors: Andreotti
authors: Patrícia O
authors: PO
authors: Prada
authors: Andrea S
authors: AS
authors: Heimann
authors: Emer S
authors: ES
authors: Ferro
mesh_terms: D016475:3T3 Cells; D017667:Adipocytes / Q000166:cytology / Q000378:metabolism; D000273:Adipose Tissue / Q000166:cytology* / Q000378:metabolism*; D000595:Amino Acid Sequence; D000818:Animals; D002846:Chromatography, Affinity; D002853:Chromatography, Liquid; D002149:Energy Intake; D005947:Glucose / Q000378:metabolism*; D007328:Insulin / Q000378:metabolism; D007333:Insulin Resistance; D008297:Male; D051379:Mice; D008969:Molecular Sequence Data; D019308:Palmitic Acid / Q000378:metabolism; D010455:Peptides / Q000032:analysis* / Q000378:metabolism*; D011485:Protein Binding; D011506:Proteins / Q000378:metabolism; D051381:Rats; D017208:Rats, Wistar; D053719:Tandem Mass Spectrometry
chemical_list: D007328:Insulin; D010455:Peptides; D011506:Proteins; D019308:Palmitic Acid; D005947:Glucose