Energetic metabolism in mouse cerebral cortex during chronic hypoxia

We measured the activities of Na+K+ ATPase and of enzymes of the glycolytic pathway, Krebs cycle, and the respiratory chain in cerebral cortex of mice exposed to chronic hypoxia for three weeks and compared their values with those of sea level controls. There were no differences in Na+K+ ATPase acti vity or in the activity of glycolytic enzymes. In the Krebs cycle, a 66% in crease of succinate dehydrogenase activity was found due to a lower Km. In contrast, respiratory chain cytochrome oxidase activity was reduced by 12% in mice exposed to hypoxia. This suggested that the metabolic demand would be satisfied despite the respiratory chain depression (cytochrome oxidase), probably due to anaerobic energy production within the mitochondria (succi nate dehydrogenase). (C) 2001 Elsevier Science Ireland Ltd. All rights rese rved.