Lipid Metabolism on the Perfused Dog Lung

The lipolytic activity of the isolated lung perfusion fluid and lung tissue was demonstrated and also the activity of whole animal plasma was measured. After perfusion, the lipid composition of both lung tissue and fatty acid composition of phospholipid subfraction were investigated. The activity of lung tissue was reduced after perfusion. From force fed dogs, the lipolytic activity of perfusion fluid and lung tissue was higher than that from fasted dogs. The dog lung injected with fibrin clots showed a reduction of the lipolytic activity and the simultaneously collected plasma lipolytic activity was decreased in comparison with that of normal dogs. It was proved that the dextran infused dog lung had lipolytic activity and these substances had a heparinlike action. Furthern ore, free fatty acid was produced into the perfusion fluid. On the otherhand, the analysis of lung lipid contents, phospholipid fraction was reduced following the reduction of the rate of choline in the dextran infused lungs. In the fatty acid composition of choline in the postperfusion lung tissue from dextran infused dogs, the amount of palmitic acid was decreased. These findings suggest that the lung perform an active lipid metabolism and the lipoprotein lipase may be situated in the capillary bed surface. The results from the analysis of lipid composition of lung tissue in this study may be related to the surface active agents