THE POSITIONAL DISTRIBUTION OF DIOLEOYL-PALMITOYL GLYCEROL INFLUENCESLYMPH CHYLOMICRON TRANSPORT, COMPOSITION AND SIZE IN RATS

The effects of 1,3-dioleoyl-2-palmitoyl glycerol (OPO) on lymph chylom icron transport, composition and size in rats were investigated in com parison with 1,2-dioleoyl-3-palmitoyl glycerol (OOP). The OPO and OOP were prepared by enzymatic transesterification reactions. The concentr ations of OPO and OOP in the preparations were 65.7 g/100 g, and the c omposition of fatty acids was similar for each. The OPO preparation co ntained triacylglycerols with 76.6% of the palmitic acid in the sn-2 p osition, whereas 100% of the oleic acid was esterified to the sn-2 pos ition in the OOP preparation. Hats were infused with lipid emulsion co ntaining 150 g/L of OPO or OOP via a stomach catheter. Lymph was colle cted through the mesenteric lymphatic trunk at 1-h intervals for 12 h. Collected lymph chylomicrons were analyzed for triacylglycerol, fatty acids, apolipoprotein A-I and particle size. The maximum transport ra tes of triacylglycerols in the OPO group were higher than those in the OOP group. The overall absorption of triacylglycerols, palmitic acid and oleic acid in the OPO group was also higher than that in the OOP g roup. In the chylomicrons, 60-70% of the fatty acids at tie sn-2 posit ion of the infused triacylglycerol was transported at the original pos ition. The transport rates of dioleoyl-palmitoyl glycerol in the OPO g roup were higher than those in the OOP group. The transport rates of a polipoprotein A-I did not differ between groups, whereas the mean diam eter of the chylomicrons in the OPO group was larger than that in the OOP group. These results indicate that OPO is absorbed and transported more effectively than OOP.