RELATIONSHIP BETWEEN CHOLESTEROL AND CHO- LESTEROL ESTERS IN THE BLOOD DURING FAT ABSORPTION.*t

Besides the true fats (compounds of glycerol and fatty acids) other substances closely related to fats are utilized in the animal economy. Some of t.hese, including cholesterol, are essential constituents of every living cell. Cholesterol exists in the body tissues in both a free condition and a combined form as esters of higher fatty acids; such as palmitic, oleic, and stearic. Cholesterol in the free condition has been known to act as a neutralizing substance to a number of different poisons (antihemolytic action against saponin,’ tetanolysin,2 etc.). Very littln, however, is known of the USC of esters of cholesterol or the part that cholesterol plays in the metabolism of fatty acids. It has been shown that during absorption of free cholesterol from the intestine it is partially esterificd and appears so in the chyle and vice versa during absorption of cholest,erol esters they are partially hydrolyxed.3 During absorption of fat free from cholesterol Bloor’ found that the cholesterol of the blood remains constant and this is confirmed in the experiments reported here, although some investigators636 have claimed an increase of cholesterol. In recent irlvestigntions,7,s on the partition