Muscle IGF-1-Induced Skeletal Muscle Hypertrophy Evokes Higher Insulin Sensitivity and Carbohydrate Use as Preferential Energy SubstrateReport as inadecuate




Muscle IGF-1-Induced Skeletal Muscle Hypertrophy Evokes Higher Insulin Sensitivity and Carbohydrate Use as Preferential Energy Substrate - Download this document for free, or read online. Document in PDF available to download.

BioMed Research International - Volume 2015 2015, Article ID 282984, 8 pages -

Research Article

Department of Anatomy, Institute of Biomedical Sciences, University of São Paulo, 05508-000 São Paulo, SP, Brazil

Centro de Ciências Naturais e Humanas CCNH, Universidade Federal do ABC UFABC, 09210-580 Santo André, SP, Brazil

Biological and Health Science Center, Mackenzie Presbyterian University, 01302-907 São Paulo, SP, Brazil

Department of Physiology and Biophysics, Institute of Biomedical Sciences, University of São Paulo, 05508-000 São Paulo, SP, Brazil

Institute Pasteur Cenci Bolognetti, DAHFMO, Unit of Histology and Medical Embryology, IIM, Sapienza University of Rome, 00161 Rome, Italy

Received 5 November 2014; Accepted 22 January 2015

Academic Editor: Pengjun Shi

Copyright © 2015 Marcelo Augusto Christoffolete et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

We characterized the metabolic profile of transgenic mice exhibiting enhanced muscle mass driven by increased mIGF-1 expression MLC-mIGF-1. As expected, 6-month-old MLC-mIGF-1 mice were heavier than age-matched wild type WT mice 37.4 ± 0.3 versus 31.8 ± 0.6 g, resp

MLC-mIGF-1 mice had higher respiratory quotient when compared to WT 0.9 ± 0.03 versus 0.74 ± 0.02, resp. suggesting a preference for carbohydrate as the major fuel source. MLC-mIGF-1 mice had a higher rate of glucose disposal when compared to WT 3.25 ± 0.14 versus 2.39 ± 0.03%-min, resp

The higher disposal rate correlated to ∼2-fold higher GLUT4 content in the extensor digitorum longus EDL muscle. Analysis of mRNA content for the glycolysis-related gene PFK-1 showed ∼3-fold upregulation in MLC-mIGF-1 animals. We also found a 50% downregulation of PGC1α mRNA levels in MLC-mIGF-1 mouse EDL muscle, suggesting less abundant mitochondria in this tissue. We found no difference in the expression of PPARα and PPARβ-δ, suggesting no modulation of key elements in oxidative metabolism. These data together suggest a shift in metabolism towards higher carbohydrate utilization, and that could explain the increased insulin sensitivity of hypertrophied skeletal muscle in MLC-mIGF-1 mice.





Author: Marcelo Augusto Christoffolete, William Jose Silva, Gracielle Vieira Ramos, Mirella Ribeiro Bento, Monique Oliveira Costa, Mi

Source: https://www.hindawi.com/



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