caa a22 4500 378849662 CHVBK 20180305123320.0 cr unu---uuuuu 161128e20030127xx s 000 0 eng 10.1515/BC.2003.016 doi (NATIONALLICENCE)gruyter-10.1515/BC.2003.016 Interaction between Leptin and InsulinSignaling Pathways Differentially AffectsJAK-STAT and PI 3-Kinase-Mediated Signalingin Rat Liver [Elektronische Daten] [J.B.C. Carvalheira, E.B. Ribeiro, F. Folli, L.A. Velloso, M.J.A. Saad] 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 leptininduced 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 crosstalk between insulin and leptin signaling pathways at the level of JAK2 and STAT5b in rat liver. Copyright © 2003 by Walter de Gruyter GmbH & Co. KG Biochemistry nationallicence Molecular biology nationallicence Cellular biology nationallicence Carvalheira J.B.C. aut Ribeiro E.B. aut Folli F. aut Velloso L.A. aut Saad M.J.A. aut Biological Chemistry Walter de Gruyter 384/1(2003-01-27), 151-159 1431-6730 384:1<151 2003 384 bchm https://doi.org/10.1515/BC.2003.016 text/html Onlinezugriff via DOI 1 research article jats NATIONALLICENCE 856 40 https://doi.org/10.1515/BC.2003.016 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Carvalheira J.B.C. aut NATIONALLICENCE 700 1- Ribeiro E.B. aut NATIONALLICENCE 700 1- Folli F. aut NATIONALLICENCE 700 1- Velloso L.A. aut NATIONALLICENCE 700 1- Saad M.J.A. aut NATIONALLICENCE 773 0- Biological Chemistry Walter de Gruyter 384/1(2003-01-27), 151-159 1431-6730 384:1<151 2003 384 bchm CC0 http://creativecommons.org/publicdomain/zero/1.0 nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-gruyter