Effect of acute hypobaric hypoxia on fatty acid metabolism in rat lung

Exposure of male albino rats in the weight range of 70-200 g to 25,000 ft of simulated altitude for 6 h at 32 degrees C caused an increase in plasma free fatty acids with decreased oxidation of palmitic acid-1-14C in lung slices of hypoxic rats. The in vivo esterification of palmitic acid-1-14C to form truglycerides, phosphatidylcholine and phosphatidylethanolamine was also low indicating decreased utilization of fatty acids by hypoxic lungs. De novo lipogenesis was observed to decreased to decrease because of decreased fatty acid biosynthesis as judged from acetate---14C incorporation. The specific activities of triglycerides, phosphatidylcholine and free cholesterol were also decreased. The decreased incorporation into phosphatidylcholine affected the incorporation into phosphatidylcholine of alveolar surfactant (2,000 g sediment fraction). The results are discussed in view of possible decreased energy status of hypoxic lungs.