Please use this identifier to cite or link to this item: http://repositorio.unicamp.br/jspui/handle/REPOSIP/59099
Type: Artigo de periódico
Title: Participation of prolactin receptors and phosphatidylinositol 3-kinase and MAP kinase pathways in the increase in pancreatic islet mass and sensitivity to glucose during pregnancy
Author: Amaral, MEC
Cunha, DA
Anhe, GF
Ueno, M
Carneiro, EM
Velloso, LA
Bordin, S
Boschero, AC
Abstract: Prolactin (PRL) exerts its biological effects mainly by activating the Janus kinase/signal transducer and activator of transcription 5 (JAK/STAT5) signaling pathway. We have recently demonstrated that PRL also stimulates the insulin receptor substrates/phosphatidylinositol 3-kinase (IRSs/PI3K) and SH2-plekstrin homology domain (SHC)/EKK pathways in islets of neonatal rats. In the present study. we investigated the involvement of the PI3K and MAP kinase (MAPK) cascades in islet development and growth in pregnant rats. The protein expression of AKT1, p70(S6K) and SHC was higher in islets from pregnant compared with control rats. Higher basal levels of tyrosine phosphorylation were found in classic transducers of insulin cell signaling (IRS1, IRS2 and SHC). Increased levels of threonine/tyrosine phosphorylation of ERK1/2 and serine phosphorylation of AKT and p70(S6K) were also detected. To assess the participation of PRL in these phenomena, pregnant and control rats were treated with an antisense oligonucleotide to reduce the expression of the PRL receptor (PRLR). Phosphorylation of AKT was reduced in islets from pregnant and control rats, whereas p70(S6K) protein levels were reduced only in islets from treated pregnant rats. Finally, glucose-induced insulin secretion was reduced in islets front pregnant but not from control rats treated with the PRLR antisense oligonucleotide. In conclusion, downstream proteins of the PI3K (AKT and p70(S6K)) and MAPK (SHC and ERK1/2) cascades are regulated by PRL signaling in islets from pregnant rats. These findings indicate that these pathways participate in the increase in islet mass and the sensitivity to glucose during pregnancy.
Country: Inglaterra
Editor: Soc Endocrinology
Rights: fechado
Identifier DOI: 10.1677/joe.1.05547
Date Issue: 2004
Appears in Collections:Unicamp - Artigos e Outros Documentos

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