Transport of cholesterol in thoracic duct lymph and serum of rhesus monkeys fed cholesterol with various food fats

Abstract

Rhesus monkeys were fed cholesterol with several food fats for 3, 10 and 30 days. After cannulation of the thoracic duct, lymph and serum were collected and fractionated into various lipoprotein classes in the preparative ultracentrifuge. It was found that in serum with high cholesterol levels the major increases in cholesterol were carried by low density lipoproteins. The amount of cholesterol in high density lipoproteins on the other hand decreased in the hypercholesterolemic animals. In lymph the chylomicron fraction transported most of the cholesterol. Slight variations in cholesterol content of different lipoprotein fractions in both lymph and serum were noted depending on the type of food fat fed. Recently absorbed cholesterol, as determined by radioactive methods after feeding tritiated cholesterol, was present in thoracic duct lymph more as cholesterol ester after the ingestion of corn oil, but more as free cholesterol after the ingestion of coconut oil. A hypothesis is proposed which suggests that the form in which absorbed cholesterol reaches the blood circulation from thoracic duct lymph may to some extent alter its subsequent metabolism.