Fat metabolism following an intravenous bolus dose of a fat emulsion and carnitine

Intravenous fat tolerance tests were performed with (carboxyl-14C)-triolein labelled Intralipid in four normal subjects with and without L-carnitine administration, 20 and 25 mg/kg body weight. The pharmacokinetics of L-carnitine was studied simultaneously with measurements of variables reflecting fat metabolism during 4 h. 3-OH-butyrate concentration in plasma was higher in all subjects when carnitine was given. No effect of carnitine was found in elimination of the exogenous triglycerides, the 14CO2 activity in expired air, concentration and specific radioactivity of non- esterified fatty acids or glucose in plasma. The data suggest that carnitine may slightly increase fatty acid oxidation in normal subjects provided that increase of 3-OH-butyrate concentration in plasma is the most sensitive variable reflecting fatty acid oxidation of the variables applied in this study.