Effects of intraalveolar oxygen concentration on alveolar fluid absorption and metabolism in isolated rat lungs

We evaluated the effects of intraalveolar oxygen concentration on alveolar fluid absorption and metabolism in isolated rat lungs. Alveolar fluid absorption was determined by measuring increase in albumin concentration in the instillate solution during 2 h of incubation. Oxidative phosphorylation was assessed by gas analysis of the solution. Glycolysis was assessed by determining glucose escape and lactate release in the solution. We found that alveolar fluid absorption did not change under hyperoxic and hypoxic experimental environments (range 100-10% oxygen). Glycolysis was reduced under hyperoxia and stimulated under hypoxia, however, lung ATP content did not change. When oxidative phosphorylation was inhibited by NaCN, both alveolar fluid absorption and lung ATP content were reduced. Our data indicate that isolated rat lungs maintain optimal energy production for alveolar fluid absorption by stimulating glycolysis, even though glycolysis alone is not enough. We conclude that alveolar fluid absorption determined in isolated rat lungs is not influenced by intraalveolar oxygen concentration in the range above 10% oxygen. Copyright (C) 1999 Elsevier Science Ireland Ltd.