Abstract
Two interventions known to cause profound changes in cellular metabolism and redox enzyme expression/activity in heart and skeletal muscle are exercise (EX), and high‐fat, high sugar “Western pattern” diet (HFHS). To determine whether heart and skeletal muscle are differentially impacted by HFHS diet and EX, Sprague‐Dawley rats were fed either standard chow (CON) or a HFHS diet for 12 weeks (HFHS). A sub‐group of HFHS rats exercise‐trained 5 days/week for 2 hours/day (HFHS+EX). Following these interventions, mitochondrial H2O2 emission (mH2O2) and Ca2+ tolerance (mCa2+) supported by pyruvate + malate + succinate, and O2 consumption (mO2) supported by glutamate+malate (GM) and palmitoyl‐carnitine (PC) was determined in permeabilized red gastrocnemius (RG) and cardiac fibers. HFHS diet increased mH2O2 ~2‐fold, and HFHS+EX decreased in RG (P<0.05) compared to CON. Surprisingly, the HFHS diet decreased mH2O2 ~2‐fold in heart compared to CON (P<0.05), and was even further decreased in HFHS+EX. Maximal PC‐supported mO2 increased in RG in both HFHS and HFHS+Ex compared to CON (P<0.05), but in heart this was only increased in HFHS+EX. Maximal GM‐supported mO2 decreased in both RG and heart with HFHS, and this decrease was prevented in HFHS+EX. Total mCa2+ increased only with HFHS+EX in both RG and heart compared to CON. These findings suggest that heart and skeletal muscle mitochondria are differentially affected by diet and exercise, which point to adaptations in cellular redox state. (Supported by NIH grant HL098780 to EJA)
Published Version
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