Figure 2.

Mitochondrial dysfunction and increased ROS generation in aged Sod1^−/− mice. A) Extramitochondrial superoxide generation in isolated mitochondria, measured using EPR. Succinate was used as substrate. B) Rate of mitochondrial H₂O₂ production measured using amplex red in state 1 (left panel) and in response to complex I-linked substrate, glutamate, and malate (right panel). C) Mitochondrial oxygen consumption, expressed as RCR. D) Rate of ATP generation in isolated mitochondria at 20 mo (n=6). E) Treadmill endurance test (run to exhaustion) results from 12- to 14-mo-old WT and Sod1^−/− mice. (n=8–10) F, G) Plasma glucose (F) and plasma lactate (G) levels measured immediately following exercise. Values are means ± se. *P < 0.05; **P < 0.01; ***P < 0.001.