Energy utilization and changes in some intermediates of glucose metabolism in normal and hypoxic rat brain after decapitation.

Energy metabolism was studied in the cerebral cortex of rats during and after hypoxia induced by breathing a gas mixture of 7% O2 in N2 for 2 h. Cortical energy stores (2ATP + ADP + phosphocreatine) remained unchanged after hypoxic treatment. Lactate rose over four-fold. Pyruvate, glucose and glucose 6-phosphate concentrations also increased significantly. Metabolic activity in the cortex expressed as the utilization of high-energy phosphates 5, 10 and 30 s after decapitation was decreased by 30% after hypoxia and remained lowered for 3 h during recovery. This was accompanied by elevated glucose consumption and lactate production, suggesting that the maintenance of the energy balance after hypoxia was partly due to activation of the glycolytic pathway. During the recovery period, these metabolic abnormalities returned towards control values, but, after 6 h of recovery the high-energy phosphate utilization increased transitorily above the control values.