Elimination of lipofundin S during the intravenous fat tolerance test in patients with low, medium, and high fasting triglyceride concentrations

The intravenous fat tolerance test with Lipofundin S (0.5 ml of 20% emulsion/kg body weight) was performed in 22 male nondiabetic patients. According to their fasting triglycerides (TG), the patients were arranged into three groups: low (less than 2.8 mmol/liter), medium (2.8-5.7 mmol/liter), and high (greater than 5.7 mmol/liter) concentrations. Fractional elimination rates of injected Lipofundin S decreased from 11.08 in low TG to 4.57%/min in high TG; they were positively correlated with fasting levels of high-density lipoprotein cholesterol but negatively with those of TG. The same pattern of correlations was observed with fractional catabolic rates of endogenous TG as measured after injection of tritium-labeled glycerol. The intravenous Lipofundin S load effected transient TG and free fatty acid elevations which were delayed in high TG. The elimination mechanisms of injected Lipofundin S and of endogenous TG are compared.