Studies on the Elimination of Exogenous Lipids from the Blood Stream. The Kinetics of the Elimination of a Fat Emulsion and of Chylomicrones in the Dog after Single Injection

The kinetics of the elimination from the blood stream of intravenously injected fat emulsion (Intralipid®) and of chylo‐micrones have been studied in the fasting dog. The elimination was estimated by determination of the arterial whole blood glyceride concentration and subtraction of the basal glyceride concentration. The same type of elimination was found in all dogs studied. The elimination consisted of two phases operating above and below a glyceride concentration of around 1.1 mM (increase above basal level) respectively. Above the concentration 1.1 mM the elimination was linear, i.e. a constant amount of glycerides was eliminated per unit time. The mean value for the elimination in this phase was 0.05 mmole/l blood per minute. Below this concentration the elimination was single exponential, i.e. a constant fraction was removed per unit time. The mean value found for this elimination was 5 per cent per minute. No greater difference was observed between the synthetic emulsion and chylomicrones. The physiological significance of the maximal elimination rate above 1.1 mM and the concentration dependent elimination below is briefly discussed.