Impact of endurance training on murine spontaneous activity, muscle mitochondrial DNA abundance, gene transcripts, and function

J Appl Physiol (1985). 2007 Mar;102(3):1078-89. doi: 10.1152/japplphysiol.00791.2006. Epub 2006 Nov 16.


We hypothesized that enhanced skeletal muscle mitochondrial function following aerobic exercise training is related to an increase in mitochondrial transcription factors, DNA abundance [mitochondrial DNA (mtDNA)], and mitochondria-related gene transcript levels, as well as spontaneous physical activity (SPA) levels. We report the effects of daily treadmill training on 12-wk-old FVB mice for 5 days/wk over 8 wk at 80% peak O(2) consumption and studied the training effect on changes in body composition, glucose tolerance, muscle mtDNA muscle, mitochondria-related gene transcripts, in vitro muscle mitochondrial ATP production capacity (MATPC), and SPA levels. Compared with the untrained mice, the trained mice had higher peak O(2) consumption (+18%; P < 0.001), lower percentage of abdominal (-25.4%; P < 0.02) and body fat (-19.5%; P < 0.01), improved glucose tolerance (P < 0.04), and higher muscle mitochondrial enzyme activity (+19.5-43.8%; P < 0.04) and MATPC (+28.9 to +32.4%; P < 0.01). Gene array analysis showed significant differences in mRNAs of mitochondria-related ontology groups between the trained and untrained mice. Training also increased muscle mtDNA (+88.4 to +110%; P < 0.05), peroxisome proliferative-activated receptor-gamma coactivator-1alpha protein (+99.5%; P < 0.04), and mitochondrial transcription factor A mRNA levels (+21.7%; P < 0.004) levels. SPA levels were higher in trained mice (P = 0.056, two-sided t-test) and significantly correlated with two separate substrate-based measurements of MATPC (P < 0.02). In conclusion, aerobic exercise training enhances muscle mitochondrial transcription factors, mtDNA abundance, mitochondria-related gene transcript levels, and mitochondrial function, and this enhancement in mitochondrial function occurs in association with increased SPA.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Blotting, Western
  • DNA, Mitochondrial / metabolism*
  • Energy Metabolism / physiology
  • Gene Expression Profiling
  • Glucose Tolerance Test
  • Male
  • Mice
  • Mitochondria, Muscle / metabolism*
  • Motor Activity / physiology*
  • Muscle, Skeletal / metabolism*
  • Oligonucleotide Array Sequence Analysis
  • Physical Conditioning, Animal / physiology*
  • Physical Endurance / physiology
  • RNA, Messenger / metabolism
  • Transcription Factors / metabolism
  • Transcription, Genetic


  • DNA, Mitochondrial
  • RNA, Messenger
  • Transcription Factors