Influences of endotoxin on oxidation of fatty acid in rabbits: a comparison between medium chain- and long chain-fatty acids

Medium chain triglyceride emulsion (MCT) which is composed of 10% emulsion of tricaprylin (C8) or long chain triglyceride emulsion (LCT, 10% Intralipos) was infused intravenously to 20 rabbits for a period of 180 min (n = 10; MCT, n = 10; LCT). Five rabbits of each group were also given lipopolysaccharide (LPS B, E. Coli 055: B5, Difco Laboratories, Detroit Michigan, U.S.A.) at a rate of 0.3mg/kg/hr to a total dose of 0.9 mg/kg. The production of ketone-bodies (acetoacetate and beta-hydroxybutyrate) was quantified. MCT was more easily oxidized than LCT, regardless of the administration of LPS. Oxidation of LCT was suppressed by the administration of LPS, while that of MCT was not suppressed. In the presence of LPS, MCT caused a more pronounced decrease in the arterial ketone body ratio (acetoacetate/beta-hydroxybutyrate) than LCT. These results indicate that MCT seems to be a better energy source than LCT under the condition where the transport of fatty acid across the mitochondrial membrane was impaired by the administration of LPS.