Please use this identifier to cite or link to this item: http://repositorio.unicamp.br/jspui/handle/REPOSIP/111
Type: Artigo de periódico
Title: Reduced pancreatic β-cell mass is associated with decreased FoxO1 and Erk1/2 protein phosphorylation in low-protein malnourished rats
Author: RAFACHO, A.
GIOZZET, V.A.G.
BOSCHERO, A.C.
ABRANTES, J.L.F.
CESTARI, T.M.
CARNEIRO, E.M.
BOSQUEIRO, J.R.
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 &#946;-cell mass was significantly reduced (&#8773;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 &#946;-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: &#946;-cell mass
Insulin signaling
Low-protein diet
Pancreatic islets
Protein phosphorylation
Country: Brasil
Editor: Associação Brasileira de Divulgação Científica
Citation: Brazilian Journal of Medical and Biological Research, v.42, n.10, p.935-941, 2009
Rights: aberto
Identifier DOI: 10.1590/S0100-879X2009001000010
Address: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-879X2009001000010
http://www.scielo.br/pdf/bjmbr/v42n10/7711.pdf
Date Issue: 2009
Appears in Collections:IB - Artigos e Materiais de Revistas Científicas

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