CLEARANCE OF CHYLOMICRONS FOLLOWING FISH-OIL AND SEAL OIL FEEDING

The aim of this study was to examine the effects of n-3 polyunsaturate d fatty acids (PUFAs) of different marine origins on the metabolism of chylomicrons following a single ingestion of oil. Two oils both rich in n-3 PUFAs but differing with respect to the intramolecular structur e of the triglycerides (TGs) were compared, the first a fish oil with the sn-2 position of TGs enriched with n-3 PUFAs and the second a seal oil with the n-3 PUFAs located in the sn-1/3 positions of the TGs. Ra diolabeled rat mesenteric lymph chylomicrons were prepared following i ntragastric administration of the respective oil in which [H-3]-choles terol and [C-14]-palmitic acid were dissolved to label the lymph chylo microns cholesterol and triglycerides, respectively. After intravenous injection of chylomicrons into unanesthetized rats, removal from plas ma of radiolabeled cholesterol and palmitate, and uptakes of radiolabe ls by the liver and spleen were measured. The disappearance of cholest erol label was faster following injection of seal oil chylomicrons com pared with fish oil chylomicrons whereas there were no differences in the disappearance of palmitate label. The recovery of palmitate label in the liver after 30 min was significantly higher following injection of fish oil chylomicrons compared with seal oil chylomicrons. Our dat a demonstrate that the metabolism of chylomicrons is affected by the i ntramolecular structure of the TG in the dietary oils rich in n-3 PUFA s but the mechanism by which the metabolism is affected is yet unknown .