Please use this identifier to cite or link to this item:
Type: Artigo de periódico
Title: Reduced pancreatic beta-cell mass is associated with decreased FoxO1 and Erk1/2 protein phosphorylation in low-protein malnourished rats
Author: Rafacho, A
Giozzet, VAG
Boschero, AC
Abrantes, JLF
Cestari, TM
Carneiro, EM
Bosqueiro, JR
Abstract: A low-protein diet leads to functional and structural pancreatic islet alterations, including islet hypotrophy. Insulin-signaling pathways are involved in several adaptive responses by pancreatic islets. We determined the levels of some insulin-signaling proteins related to pancreatic islet function and growth in malnourished rats. Adult male Wistar rats (N = 20 per group) were fed a 17% protein (normal-protein diet; NP) or 6% protein (low-protein diet; LP), for 8 weeks. At the end of this period, blood glucose and serum insulin and albumin levels were measured. The morphometric parameters of the endocrine pancreas and the content of some proteins in islet lysates were determined. The beta-cell mass was significantly reduced (congruent to 65%) in normoglycemic but hypoinsulinemic LP rats compared to NP rats. Associated with these alterations, a significant 30% reduction in insulin receptor substrate-1 and a 70% increase in insulin receptor substrate-2 protein content were observed in LP islets compared to NP islets. The phosphorylated serine-threonine protein kinase (pAkt)/Akt protein ratio was similar in LP and NP islets. The phosphorylated forkhead-O1 (pFoxO1)/FoxO1 protein ratio was decreased by 43% in LP islets compared to NP islets (P < 0.05). Finally, the ratio of phosphorylated-extracellular signal-related kinase 1/2 (pErk1/2) to total Erk1/2 protein levels was decreased by 71% in LP islets compared to NP islets (P < 0.05). Therefore, the reduced beta-cell mass observed in LP rats is associated with the reduction of phosphorylation in mitogenic-related signals, FoxO1 and Erk proteins. The cause/effect basis of this association remains to be determined.
Subject: beta-cell mass
Insulin signaling
Low-protein diet
Pancreatic islets
Protein phosphorylation
Country: Brasil
Editor: Assoc Bras Divulg Cientifica
Citation: Brazilian Journal Of Medical And Biological Research. Assoc Bras Divulg Cientifica, v. 42, n. 10, n. 935, n. 941, 2009.
Rights: aberto
Date Issue: 2009
Appears in Collections:Unicamp - Artigos e Outros Documentos

Files in This Item:
File Description SizeFormat 
WOS000270233400010.pdf1.29 MBAdobe PDFView/Open

Items in DSpace are protected by copyright, with all rights reserved, unless otherwise indicated.