Swim training of monosodium l -glutamate-obese mice improves the impaired insulin receptor tyrosine phosphorylation in p
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ORIGINAL ARTICLE
Swim training of monosodium L-glutamate-obese mice improves the impaired insulin receptor tyrosine phosphorylation in pancreatic islets Rosiane Aparecida Miranda • Renato Chaves Souto Branco • Clarice Gravena • Luiz Felipe Barella • Claudine´ia Conationi da Silva Franco • Ana Eliza Andreazzi Ju´lio Cezar de Oliveira • Maria Cecı´lia Picinato • Paulo Cezar de Freitas Mathias
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Received: 12 March 2012 / Accepted: 6 September 2012 / Published online: 16 September 2012 Ó Springer Science+Business Media, LLC 2012
Abstract The goal of the present study was to investigate changes on glucose homoeostasis and of the insulin receptor (IR) and insulin receptor substrate-1 (IRS-1) signalling in pancreatic islets from MSG-obese mice submitted to or not submitted to swim training. Swim training of 90-day-old MSG mice was used to evaluate whether signalling pathways of the IR and IRS-1 in islets are involved with the insulin resistance and glucose intolerance observed in this obese animal model. The results showed that IR tyrosine phosphorylation (pIR) was reduced by 42 % in MSG-obese mice (MSG, 6.7 ± 0.2 arbitrary units (a.u.); control, 11.5 ± 0.4 a.u.); on the other hand, exercise training increased pIR by 76 % in MSG mice without affecting control mice (MSG, 11.8 ± 0.3; control, 12.8 ± 0.2 a.u.). Although the treatment with MSG increased IRS-1 tyrosine phosphorylation (pIRS-1) by 96 % (MSG, 17.02 ± 0.6; control, 8.7 ± 0.2 a.u.), exercise training also increased it in both groups (control, 13.6 ± 0.1; MSG, 22.2 ± 1.1 a.u.).
R. A. Miranda R. C. S. Branco C. Gravena L. F. Barella C. C. da Silva Franco J. C. de Oliveira P. C. de Freitas Mathias (&) Laboratory of Secretion Cell Biology, Department of Cell Biology and Genetics, State University of Maringa´/UEM, Block H67, Room 19, Avenue Colombo, 5790, Maringa´, PR 87020-900, Brazil e-mail: [email protected] A. E. Andreazzi Laboratory of Cell Biology, Department of Biology, Federal University of Juiz de Fora, Juiz de Fora, MG, Brazil M. C. Picinato Laboratory of Morphophysiology and Genetics, Federal University of Para´/UFPA, Altamira, PA, Brazil
Current research shows that the practice of swim training increases the tyrosine phosphorylation of IRS-1 which can modulate the effect caused by obesity in insulin receptors. Keywords IR Islets
MSG-obese mice Swim training IRS-1
Introduction Obesity is becoming one of the most important increasing physiopathological conditions worldwide. Insufficient physical activity and excessive caloric intake are the causes for increasing body weight [1, 2]. The obesity produced by neonatal treatment with monosodium L-glutamate (MSG) is a major tool to study the effects of obesity on different metabolic parameters. This model is characterised by hyperinsulinaemia and higher insulin secretion [3] or early hyperglycaemia in MSG-treated mice [4, 5]. MSG-obese rodents present a severe tissue insulin resistance, which is observed as a dysfunction of the insulin receptor (IR) as well as in internal signal transduction
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