| Abstract: | Seven untrainedvolunteers 3 men, 4 women, 20.1 ± 2.0 (SD) yr, 66.0 ± 11.0 kg, 171 ± 13 cm] participated in a 10-day cycle exercisetraining program. Resting muscle samples were obtained from vastuslateralis before and after 5 and 10 days of training. Mitochondrial ATPproduction rate (MAPR) was assayed in isolated mitochondria by using abioluminescence technique and referenced to the activity of glutamatedehydrogenase in the muscle sample. MAPR increased 136 and 161% after10 days of training for the mitochondrial substrate combinationspyruvate + palmitoyl-L-carnitine +  -ketoglutarate + malate andpalmitoyl-L-carnitine + malate, respectively. Total muscle glutamate dehydrogenase and citrate synthaseactivity increased 53 and 16%, respectively, after 5 days but did notsignificantly increase further after 10 days. The results from thepresent study indicate that MAPR, measured by using the substratecombinations pyruvate + palmitoyl-L-carnitine + -ketoglutarate + malate andpalmitoyl-L-carnitine + malate, can rapidly increase in response to endurance training. |
