Fate of Triglycerides and Phospholipids of Lymph and Artificial Fat Emulsions: Disappearance From the Circulation

Abstract

Artificial fat emulsions labeled in either triglyceride or phospholipid component were administered to unanesthetized normal dogs to determine the disappearance rates of the two lipids from the circulation. Similar experiments were carried out using lymph from donor dogs fed I¹³¹-triolein or P³²-phosphate with unlabeled triglyceride. Triglycerides were found to be rapidly removed from the circulation whether they were administered as an artificial fat emulsion or as a physiological emulsion, lymph. On the other hand, the emulsifying agents, liver lecithin or lymph phospholipid, required several hours for removal from the circulation. Evidence is presented that the slow disappearance rate of chylomicron phospholipids cannot be accounted for by exchange with plasma lipoproteins and indicates a slow removal of chylomicra phospholipid from the circulating blood. These findings are discussed in reference to current concepts of the chemical structure of lymph chylomicrons and of particulate fat in an artificial fat emulsion.