mRNAs of enzymes involved in energy metabolism and mtDNA are increased in endurance-trained athletes.
Improvements in endurance capacity by training are associated with structural and biochemical adaptations of working muscles that affect the mitochondrial compartment. We investigated whether the 1.8-fold higher mitochondrial volume density in a group of endurance-trained athletes compared with untrained subjects was reflected by higher steady-state levels of mRNAs coding for components of the oxidative phosphorylation pathway using a quantitative polymerase chain reaction approach. We found that mitochondrially encoded RNAs (cytochrome-c oxidase subunit I, NADH reductase subunit 6, 16S rRNA), as well as nuclear-encoded RNAs (cytochrome-c oxidase subunit IV, succinate dehydrogenase, fumarase) are all increased coordinately in the athletes (1.54- to 1.94-fold). In addition, mitochondrial (mt) DNA concentration was also 1.55-fold higher in the trained athletes, whereas genomic DNA was not changed. Our findings thus show similar RNA expression of mitochondrially encoded genes in sedentary and endurance-trained subjects, whereas pretranslational control mechanisms account for higher levels of nuclear-encoded RNAs in the athletes.
Puntschart
A
A
Department of Anatomy, University of Bern, Switzerland.
Claassen
H
H
Jostarndt
K
K
Hoppeler
H
H
Billeter
R
R
D000328:Adult; D004272:DNA, Mitochondrial / Q000235:genetics*; D004734:Energy Metabolism; D004798:Enzymes / Q000235:genetics* / Q000378:metabolism*; D006801:Humans; D008297:Male; D010807:Physical Endurance; D016133:Polymerase Chain Reaction; D012333:RNA, Messenger / Q000378:metabolism*; D013177:Sports / Q000502:physiology*
D004272:DNA, Mitochondrial; D004798:Enzymes; D012333:RNA, Messenger