Absorption of Cholesterol Esters in the Lymph-Fistula Rat

Abstract

Free and esterified cholesterol fractions in thoracic duct lymph of rats were determined after the administration of emulsions containing saline, albumin, taurocholate, oleic acid and free cholesterol, or fatty acid esters of cholesterol. Total lymph cholesterol increased within 3 hours after feeding free cholesterol or the natural cholesterol esters. Cholesterol butyrate was absorbed as well as free cholesterol, while the esters of oleic and linoleic acids, were absorbed slower and less efficiently. Saturated acid esters, laurate and stearate were absorbed slowly and inefficiently. Administration of cholesterol trimethylacetate, which is resistant to the hydrolytic action of pancreatic cholesterol esterase, did not result in any increase in lymph cholesterol above the control level. Throughout all groups in which absorption of cholesterol occurred, the absorbed cholesterol in lymph was esterified from 87% to 95%. The data are in agreement with the concept that dietary cholesterol esters are hydrolyzed in the intestinal lumen prior to absorption of the cholesterol moiety as free cholesterol.