[Effect of lipid infusions on triglyceride and protein metabolism]

In metabolically healthy volunteers we investigated the influence of long and medium chained triglycerides on the kinetic of the free fatty acids in blood and on protein metabolism. During a three hour infusion of lipid emulsion (infusion rate 120 mg/kg BW X h) consisting of 50% medium and 50% long chained triglycerides we observed a significant increase of the concentrations of the medium chained free fatty acids (caprylic and capric acid), which decreased down to basic values with a half life of 30 minutes immediately after the infusion period. The total concentration of free fatty acids was higher during the infusion of a MCT/LCT mixture than during the infusion of pure LCT. Glucose infused simultaneously reduced the metabolism of the free fatty acids. MCT induced higher ketonemia and ketonuria than LCT, the ketogenesis could be suppressed by additional glucose. Compared to the glycerol control infusion the total nitrogen excretion was reduced under lipid infusion. Beside the lower excretion of Glu + Gln and Ala the excretion of 3-methylhistidine was reduced, which indicates a decreased on muscle protein turnover as referred to increased free fatty acids and the ketone body concentrations respectively.