Experimental study on lipid metabolism of the lung in rats administered various kinds of fats and oils.

Wistar male rats were administrated Various Kinds of fats orally by a stomach tube, and each lipid content and fatty acid composition of each lipid fraction in the lung and liver were measured at time intervals of 3, 6 and 9 hours after administration. Both lung and liver showed increase of each lipid content, especially that of phospholipid content, 6 hours after the administration of safflower oil and trilinolein. In the fatty acid composition of the simple lipid fraction, increase of linoleic acid was recognized , and in the fatty acid compoition of the phospholipid fraction, increase of linoleic and arachidonic acids. From this fact, it is considered that the conversion of linoleic acid into arachidonic acid takes place in the lung as weel as in the liver. After the administration of safflower oil, any marked change could not be recognized in the lipid composition and the fatty acid composition of each fraction in the heart, kidney and spleen. After the administration of fats, the lipoprotein lipase (LPL) activity of the lung was enhanced in an earlier time than that of plasma, and lowered afterward. Following this change, each lipid content of the lung showed increase earlier than that of liver, and decrease afterward. From this fact it is suggested that the lung reacts to the exogenous fats as well as the liver, and in an earlier time, produces LPL, hydrolyzing the fats and incorporating the hydrolyzed fats to cope with alimentary hyperlipemia.