In studies directed at determining the activities of selected enzymes in lung tissue after in vivo exposure to hyperoxia, 70 day old rats were exposed to 85% or 90% O 2 for 1-14 days. After 7 days of exposure to 90% O 2 (1 atm), superoxide desmutase activities in mitochondrial and cytosolic fractions increased, respectively, to 245 and 145% of control; glutathione peroxidase, glutathione reductase, and glucose 6 phosphate dehydrogenase activities increased, respectively, to 317, 175 and 413% of control. The levels of reduced glutathione and total nonprotein sulfhydryl compounds were elevated to 195% and 365% of control. Similar changes were observed in rats exposed to 85% O 2 for up to 14 days, but to a lesser degree. The changes are interpreted as a reflection of the overall magnitude of oxidant induced lung injury reparative process. The results suggest that hyperoxia induces an increase in lung 'antioxidant' defense capabilities. This apparent adaptive response may be important in decreasing the susceptibility of lung tissue to continued O 2 toxicity.
|Original language||English (US)|
|Title of host publication||American Journal of Physiology|
|Number of pages||7|
|State||Published - 1976|
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