出版社：American Society for Biochemistry and Molecular Biology
摘要：Prior studies have suggested that FAs liberated in the smallintestine from ingested 1,3-diacylglycerol (DAG) are inefficientlyincorporated into triglyceride (TG) in enterocytes, with lesschylomicron TG entering the circulation postprandially. We foundless TG, but more monacylglyerol and DAG, with similar totalacylglycerol in newly secreted chylomicrons after oral DAG ortriacylglycerol (TAG). However, clearance of DAG-chylomicronswas more rapid than that of TAG-chylomicrons; this was associatedwith more efficient in vitro LPL-mediated lipolysis of DAG-derivedchylomicrons. Intravenously infused DAG was also cleared fasterthan TAG in normal mice, via both LPL-mediated lipolysis andapolipoprotein E (apoE)-dependent hepatic uptake. Infusionsof TAG, but not DAG, increased plasma TG levels. Greater deliveryof DAG-derived FA to the liver during infusion of DAG led togreater TG secretion versus TAG; this allowed the maintenanceof similar hepatic TG levels after DAG and TAG infusions. Ofnote, apoB secretion was similar after DAG versus TAG, indicatingthe assembly of larger very low density lipoproteins after DAG.In conclusion, reduced plasma TG levels, after oral or intravenousDAG, result from more efficient clearance of DAG by both LPLlipolysis and apoE-mediated hepatic endocytosis. DAG emulsionsmay by useful for intravenous nutrition in people with preexistinghypertriglyceridemia.Supplementary key words triglycerides • lipoprotein metabolism • chylomicron metabolism
Abbreviations: AG, acylglycerol; AOX, acyl-coenzyme A oxidase; apoB, apolipoprotein B; CE, cholesteryl ester; CEt, cholesterol oleoyl ether; CPT-1, carnitine palmitoyltransferase-1; DAG, diacylglycerol; DO, diolein; MAG, 1-monoacylglycerol; PhP, postheparinized plasma; PPAR, peroxisome proliferator-activated receptor ; TAG, triacylglycerol; TG, triglyceride; TO, triolein
, peroxisome proliferator-activated receptor 
