The effects of cytoplasmic transfer of mtDNA in relation to whole-body endurance performance

The purpose of this study was to examine the relation between whole-body ae robic capacity and mitochondrial facilities. The mitochondrial enzyme syste m of oxidative phosphorylation (OXPHOS) is encoded both by mitochondrial DN A (mtDNA) and nuclear DNA. To identify the effect of mtDNA on whole-body ae robic capacity, we fused the platelets of the study subjects that contained mtDNA but that lacked nuclear DNA with p(0) HeLa cells, which lacked mtDNA , and isolated repopulated cybrids. The mitochondrial respiratory functions of the cybrids, estimated from cell oxygen consumption and cytochrome-c ox idase (CCOX), were compared between endurance athletes and sedentary contro ls. The oxygen consumption was 18.5 +/-3.9 and 18.2 +/-4.1 nmol/min/ml/10(7 ) cells in athletes and controls, respectively. The CCOX activity was 98.8 +/- 17.5 and 116.7 +/-9.8%, compared with fibroblasts in athletes and contr ols, respectively. No significant difference was noted between groups in ei ther cell oxygen consumption or CCOX activity. These results show that the OXPHOS enzymes coded by mtDNA do not strongly influence whole-body aerobic fitness.