N-3 fatty acids and chylomicron metabolism in the rat.
Dietary n-3 fatty acids (FAs) reduce postprandial triacylglycerol concentrations in humans by unknown mechanisms. Our goals were to reproduce this phenomenon in the rat, and then to determine the mechanism. In an oral fat tolerance study two groups of rats were fed diets containing 2.1% ethyl esters of n-3 FA or olive oil for 2 weeks. After gavaging with emulsified soybean oil, the postprandial chylomicron triacylglycerol levels in the n-3 FA group were reduced by 40% (P < 0.05). The hypothesis that n-3 FA feeding reduced chylomicron production/secretion from the gut was tested by blocking chylomicron removal with Triton WR1339 before gavaging the rats with the fat load. This completely eliminated the hypochylomicronemic effect suggesting that chylomicron input was not inhibited by n-3 FAs. Chylomicron clearance was studied by injecting chylomicrons containing radioactive retinyl esters and triacylglycerol into rats from both groups. Pre-feeding with n-3 FAs accelerated the removal of chylomicron triacylglycerol and retinyl esters from the plasma with significantly lower fractions of dose remaining at 2, 4, and 8 min post-injection for both tracers. These findings suggest than n-3 FAs reduce postprandial chylomicronemia in the rat by accelerating chylomicron lipid clearance.
Harris
W S
WS
Department of Medicine, University of Kansas Medical Center, Kansas City 66160, USA.
Hustvedt
B E
BE
Hagen
E
E
Green
M H
MH
Lu
G
G
Drevon
C A
CA
D000818:Animals; D001835:Body Weight; D002914:Chylomicrons / Q000097:blood / Q000378:metabolism*; D003198:Computer Simulation; D004041:Dietary Fats / Q000008:administration & dosage / Q000494:pharmacology; D015525:Fatty Acids, Omega-3 / Q000008:administration & dosage / Q000494:pharmacology*; D007421:Intestine, Small / Q000378:metabolism; D008196:Lymph / Q000737:chemistry; D008297:Male; D008954:Models, Biological; D010316:Particle Size; D010743:Phospholipids / Q000378:metabolism; D010938:Plant Oils / Q000737:chemistry / Q000378:metabolism; D011092:Polyethylene Glycols / Q000494:pharmacology; D051381:Rats; D017208:Rats, Wistar; D013501:Surface-Active Agents / Q000494:pharmacology; D014280:Triglycerides / Q000097:blood / Q000378:metabolism*; D014801:Vitamin A / Q000031:analogs & derivatives / Q000097:blood / Q000378:metabolism
D002914:Chylomicrons; D004041:Dietary Fats; D015525:Fatty Acids, Omega-3; D010743:Phospholipids; D010938:Plant Oils; D013501:Surface-Active Agents; D014280:Triglycerides; D014801:Vitamin A; D011092:Polyethylene Glycols; C016811:tyloxapol