Interaction between leptin and insulin signaling pathways differentially affects JAK-STAT and Pl 3-kinase-mediated signaling in rat liver
Articolo
Data di Pubblicazione:
2003
Citazione:
Interaction between leptin and insulin signaling pathways differentially affects JAK-STAT and Pl 3-kinase-mediated signaling in rat liver / J.B.C. Carvalheira, E.B. Ribeiro, F. Folli, L.A. Velloso, M.J.A. Saad. - In: BIOLOGICAL CHEMISTRY. - ISSN 1431-6730. - 384:1(2003), pp. 151-159.
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.
Tipologia IRIS:
01 - Articolo su periodico
Keywords:
DNA-binding proteins; Drug effects; Insulin physiology; Leptin pharmacology; Liver; Metabolism; Protein-tyrosine kinase; Signal transduction; Biochemistry
Elenco autori:
J.B.C. Carvalheira, E.B. Ribeiro, F. Folli, L.A. Velloso, M.J.A. Saad
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