Abstract :
This study aimed to 1) develop a method that completely separated hepatic (VLDL1, VLDL2) and intestinal [chylomicron (CM)] lipoproteins and 2) use the method to measure triacylglycerol (TAG) kinetics in these lipoproteins in the fed and fasting state in healthy subjects, using intravenous [[sup.2][H.sub.5]]glycerol as the tracer. An immunoaffinity method that completely separated hepatic and intestinal particles using sequential binding to three antibodies to apolipoprotein B-100 (apoB-100) was established and validated. Six healthy volunteers were studied in a fasted and continuous feeding study (study 1). Five additional healthy volunteers were studied in a continuous feeding study that included an oral [[sup.13][C.sub.3]]glycerol tripalmitin tracer (study 2). In both studies, an intravenous bolus of [[sup.2][H.sub.5]]glycerol was administered to label TAG in hepatic and intestinal lipoproteins. In both feeding studies there was sufficient incorporation of the [[sup.2][H.sub.5]]glycerol tracer into the exogenous lipoproteins to enable isotopic enrichment to be measured. In study 2, the oral tracer enrichment in VLDL1 was very-low-density lipoprotein; chylomicron; stable isotopes; immunoaffinity; postprandial doi: 10.1152/ajpendo.00105.2013