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(Reference retrieved automatically from Web of Science through information on FAPESP grant and its corresponding number as mentioned in the publication by the authors.)

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

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Christoffolete, Marcelo Augusto [1, 2] ; Silva, William Jose [1] ; Ramos, Gracielle Vieira [1] ; Bento, Mirella Ribeiro [1] ; Costa, Monique Oliveira [1] ; Ribeiro, Miriam Oliveira [3] ; Okamoto, Maristela Mitiko [4] ; Lohmann, Tania Helena [1] ; Machado, Ubiratan Fabres [4] ; Musaro, Antonio [5] ; Moriscot, Anselmo Sigari [1]
Total Authors: 11
[1] Univ Sao Paulo, Inst Biomed Sci, Dept Anat, BR-05508000 Sao Paulo - Brazil
[2] Univ Fed ABC UFABC, CCNH, BR-09210580 Santo Andre, SP - Brazil
[3] Univ Prebiteriana Mackenzie, Biol & Hlth Sci Ctr, BR-01302907 Sao Paulo - Brazil
[4] Univ Sao Paulo, Inst Biomed Sci, Dept Phys & Biophys, BR-05508000 Sao Paulo - Brazil
[5] Univ Roma La Sapienza, Unit Histol & Med Embryol, Inst Pasteur Cenci Bolognetti, DAHFMO, IIM, I-00161 Rome - Italy
Total Affiliations: 5
Document type: Journal article
Web of Science Citations: 5

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 similar 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 similar to 3-fold upregulation in MLC/mIGF-1 animals. We also found a 50% downregulation of PGC1 alpha mRNA levels in MLC/mIGF-1 mouse EDL muscle, suggesting less abundant mitochondria in this tissue. We found no difference in the expression of PPAR alpha and PPAR beta/delta, 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. (AU)

FAPESP's process: 12/22488-2 - Expression of microRNAs in the skeletal muscle plasticity: the possible interrelationships with MuRFs effect in the regenerative process
Grantee:William Jose da Silva
Support type: Scholarships in Brazil - Doctorate (Direct)