Assimilation and dissimilation of fatty acids by the rat liver

Abstract

Up to 60% of i.v. injected doses of 1-C14 palmitic acid was found in the liver 15 minutes after injection, two thirds in the form of triglycerides and the rest as phospholipids. Almost no radioactive UFA could be demonstrated in the liver or in blood plasma. Thereafter, the activity in the triglyceride fraction fell rapidly, only 50% remaining after 1 hour. At the same time the phospholipid activity increased. With 1-C14 linoleic acid a similar pattern was found, except that the percentage retained in the liver was lower and maximum retention was found after 5 minutes. Fifteen minutes after injection of 1-C14 palmitate most of the radioactive glycerides in the liver were found in the microsomes and mitochondria, with very little in the floating fat. Equilibration between these cytoplasmatic particles occurred only after 2 hours. Perfusion of the liver in situ with blood or blood substitutes, after various periods following 1-C14 palmitic acid injection, caused a release of about 5–20% of the liver triglycerides and 0.5–2% of the liver phospholipids per hour.