Comparative Studies on Absorption and Utilization of Medium and Long Chain Triglycerides in Rats

Abstract

The intestinal absorption and postabsorptive tissue utilization of medium chain triglyceride was studied in comparison with those of long chain triglyceride using l-¹⁴C-labeled MCT and LCT as well as similarly labeled Na-octanoate and Na-oleate in rats. Evolution of ¹⁴CO₂ was measured employing closed CO₂ trapping system, as a measure of absorption and/or utlization. For the study on the utilization of these lipids in metabolic derangement, acute and chronic, ethanol induced liver damages were produced in rats, and similar experiments were carried out. For the production of chronic ethanol liver, an experimental diet containing ethanol and solidified with agar, was used with success. The following are the results: 1) Absorption and utilization as measured from ¹⁴CO₂ evolution are much faster for MCT compared with LCT, and orally fed MCT is almost completely utilized within 7 hours. 2) Absorption of orally administered MCT is not much dependent upon the presence of bile in the intestine, and MCT directly placed in the cecum is absorbed if bile acids and lipase were available. 3) Absorption and utilization of both MCT and LCT are impaired markedly in acute liver damage induced by ethanol. Since intestinal transit of the oral dose of lipid was impaired in acute ethanol intoxication, intravenous administration of emulsified lipid suspensions was done for utilization studies. In chronic ethanol intoxication, absorption and utilization of MCT are little affected in comparison with LCT which is poorly utilized under the same conditions.