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Type: Artigo de periódico
Title: Interaction Between Leptin And Insulin Signaling Pathways Differentially Affects Jak-stat And Pi 3-kinase-mediated Signaling In Rat Liver.
Author: Carvalheira, José B C
Ribeiro, Eliane B
Folli, Franco
Velloso, Lício A
Saad, Mario J A
Abstract: Chronic leptin treatment markedly enhances the effect of insulin on hepatic glucose production unproportionally with respect to body weight loss and increased insulin sensitivity. In the present study the cross-talk between insulin and leptin was evaluated in rat liver. Upon stimulation of JAK2 tyrosine phosphorylation, leptin induced JAK2 co-immunoprecipitation with STAT3, STAT5b, IRS-1 and IRS-2. This phenomenon parallels the leptin-induced tyrosine phosphorylation of STAT3, STAT5b, IRS-1 and IRS-2. Acutely injected insulin stimulated a mild increase in tyrosine phosphorylation of JAK2, STAT3 and STAT5b. Leptin was less effective than insulin in stimulating IRS phosphorylation and their association with PI 3-kinase. Simultaneous treatment with both hormones yielded no change in maximal phosphorylation of STAT3, IRS-1, IRS-2 and Akt, but led to a marked increase in tyrosine phosphorylation of JAK2 and STAT5b when compared with isolated administration of insulin or leptin. This indicates that there is a positive cross-talk between insulin and leptin signaling pathways at the level of JAK2 and STAT5b in rat liver.
Subject: Animals
Dna-binding Proteins
Electrophoresis, Polyacrylamide Gel
Insulin Receptor Substrate Proteins
Intracellular Signaling Peptides And Proteins
Janus Kinase 2
Milk Proteins
Phosphatidylinositol 3-kinases
Protein-tyrosine Kinases
Proto-oncogene Proteins
Rats, Wistar
Rats, Zucker
Stat3 Transcription Factor
Stat5 Transcription Factor
Signal Transduction
Citation: Biological Chemistry. v. 384, n. 1, p. 151-9, 2003-Jan.
Rights: fechado
Identifier DOI: 10.1515/BC.2003.016
Date Issue: 2003
Appears in Collections:Unicamp - Artigos e Outros Documentos

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