Oxygen consumption by rat lung after in vivo hyperoxia.

We studied the influence of 48 and 96 hours of in vivo hyperoxia (O2 greater than 98 per cent) on O2 consumption by rat lung slices. After 48 hours of hyperoxia, lung O2 consumption expressed per mg of deoxyribonucleic acid or per left lung decreased to approximately 70 per cent of that of lungs from rats exposed to compressed air. After 96 hours of hyperoxia, there was no difference in lung O2 consumption per mg of deoxyribonucleic acid between rats exposed to O2 and those exposed to air, but lung O2 consumption per left lung was higher in rats exposed to O2 than in those exposed to compressed air. Lung ribonucleic acid content and the ratio of ribonucleic acid to deoxyribonucleic acid were significantly increased after 96 hours of hyperoxia. We concluded that the rate of lung metabolism is altered after in vivo exposure to high PO2.