Pulmonary O2 toxicity: energy metabolism and data analysis.

Abstract

SummaryComparison of homogenates vs mitochondrial preparations in evaluating in vivo respiration and oxidative phosphorylation in lung from rats exposed to 1.5 ATA O2 for 24, 27, and 30 hr showed that homogenates from experimentally exposed rats may contain extramitochondrial factors inhibitory to respiration which are washed out in mitochondrial isolation procedures. Thus, the use of homogenates is preferable to isolated mitochondria, since they more nearly reflect in vivo oxidative phosphorylation in pulmonary oxygen toxicity studies.Intercomparison of methods of expressing lung respiration rates and ATP concentration were made in lung of rat subjected to 1.0 and 1.5 ATA O2 exposures. Care should be exercised in selecting the means for expressing data. Our results indicate that the preferred method for expressing respiration rates is microliters O2/milligram mitochondrial protein per minute, and for expressing ATP levels is micromoles ATP/milligram mitochondrial protein, in pulmonary O2 toxicity studies...