Effects of human pancreatic lipase-colipase and carboxyl ester lipase on eicosapentaenoic and arachidonic acid ester bonds of triacylglycerols rich in fish oil fatty acids.
Fish oil chylomicrons, obtained from mesenteric duct chyle of rats fed [3H]20:5 and [14C]20:4 or [3H]20:5 and [14C]18:2 in a fish oil emulsion, were incubated with human pancreatic lipase-colipase, human carboxyl ester lipase (CEL) and human duodenal contents. With duodenal contents, the triacylglycerols labelled with [3H]20:5 and [14C]20:4 were rapidly converted to free fatty acids (FFA) and monoacylglycerols. Also during incubation with lipase-colipase the [3H]- and [14C]triacylglycerols disappeared completely and at equal rates, but in this case much [3H]20:5 and [14C]20:4 accumulated in diacylglycerols. When CEL was also added, the rate of disappearance of [3H]- and [14C]triacylglycerols increased and the radioactivity of diacylglycerols decreased markedly. During incubation of chylomicrons labelled with [3H]20:5 and [14C]18:2 with lipase-colipase, the rates of hydrolysis of [3H]- and [14C]triacylglycerols were similar, but more [3H]20:5 than [14C]18:2 accumulated in diacylglycerols. The accumulation of [3H]diacylglycerol was reduced by adding CEL. Also when fatty acids were analyzed by gas chromatography, 20:5 was enriched in remaining triacylglycerol and in diacylglycerol after incubation with lipase-colipase alone. The data thus indicate that both lipase-colipase and CEL participate in the hydrolysis of 20:5 and 20:4 ester bonds of dietary triacylglycerol.
Chen
Q
Q
Department of Medicine, University of Lund, Sweden.
Sternby
B
B
Akesson
B
B
Nilsson
A
A
D000818:Animals; D001095:Arachidonic Acids / Q000378:metabolism*; D002250:Carbon Radioisotopes; D002265:Carboxylic Ester Hydrolases / Q000494:pharmacology*; D002914:Chylomicrons; D003089:Colipases / Q000494:pharmacology*; D004386:Duodenum / Q000187:drug effects / Q000378:metabolism*; D005395:Fish Oils / Q000378:metabolism*; D006801:Humans; D007700:Kinetics; D008049:Lipase / Q000494:pharmacology; D008297:Male; D011506:Proteins / Q000494:pharmacology*; D051381:Rats; D011919:Rats, Inbred Strains; D014280:Triglycerides / Q000378:metabolism*
D001095:Arachidonic Acids; D002250:Carbon Radioisotopes; D002914:Chylomicrons; D003089:Colipases; D005395:Fish Oils; D011506:Proteins; D014280:Triglycerides; D002265:Carboxylic Ester Hydrolases; D008049:Lipase