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Research Article Free access | 10.1172/JCI107216
Pulmonary Division, Veterans Administration—George Washington University Medical Center, Washington, D. C. 20422
Find articles by Gacad, G. in: JCI | PubMed | Google Scholar
Pulmonary Division, Veterans Administration—George Washington University Medical Center, Washington, D. C. 20422
Find articles by Massaro, D. in: JCI | PubMed | Google Scholar
Published March 1, 1973 - More info
We studied the time-course of the influence of in vivo hyperoxia on lung mechanics and on protein synthesis. After 24 h of exposure to greater than 98% O2 at 1 atm there were no alterations in descending pressure-volume curves (air or saline) of lungs excised from O2-exposed rats compared to control rats. After 48 h of hyperoxia there was a decrease in lung compliance.
To study protein synthesis, as indicated by L-[U-24C] leucine incorporation into protein, lung slices were incubated with L-[U-14C]leucine and surface-active material then obtained by ultracentrifugation of lung homogenates. We measured radioactivity in total protein and in protein in the surface-active fraction. There were no alterations in incorporation after 12 h of hypertoxia. After 24 h of hyperoxia there were significant decreases (P<0.05) in L-[U-14C]leucine incorporation into total protein and into protein of the surface-active fraction. After 48 h of hyperoxia incorporation into protein of the surface-active fraction was decreased to a greater extent than incorporation into total protein, 63±4% and 75±5%, respectively, (P<0.025).
These studies show that hyperoxia produces a major decrease in protein synthesis, including synthesis of protein in a surface-active fraction, before the onset of any detectable changes in the static compliance of excised lungs.