Effects of Exposures to 100% Oxygen on Cellular Metabolism

Studies were made of the biochemical toxicology of oxygen atmospheres. These studies were divided into two parts: (a) effects of pure oxygen atmospheres at ambient pressure on the cellular bioenergetics of monkey (Macaca mulatta) liver and kidney tissue, and (b) effects of pure oxygen atmospheres at approximately one-third atmospheric pressure on rat liver tissues. Monkeys were exposed for 4, 7, and 12 days to 100% oxygen at 748 mm Hg pressure in the Thomas dome. Surviving animals (3, 3, and 2) were compared with 5 normal ambient controls. Allowing for variations in animals there appeared to be a trend to diminished kidney ATP levels and to lowered P/O values obtained with liver or kidney mitochondria by the Warburg technique using succinate substrate. Isolated mitochondria from exposed animals showed respiratory control. Rats were exposed for 1, 4, 7, or 14 days to 100% oxygen at 257 mm Hg pressure in the Thomas dome. Experiments also were run in which 14-day exposed rats were returned to ambient air 1 and 48 hours prior to sacrifice. Experimental animals were paired with ambient controls. Elevations in tissue ATP concentrations were observed after 1, 4, and 7-day exposures; there was no significant elevation at 14 days. There was some indication of elevated Q(O/N) values in states 4 and 3 with isolated mitochondria from exposed animals using succinate substrate. Average respiratory control values were also elevated.