Distribution of conjugated linoleic acid and metabolites in different lipid fractions in the rat liver

Conjugated linoleic acid (CLA) is known to pro- vide certain health benefits in experimental animal models. The major CLA isomer in food is c 9, t 11-CLA. A primary ob- jective of this study was to investigate the uptake of c 9, t 11- CLA and its downstream metabolites into various lipid frac- tions in the liver of rats fed either a high or low CLA diet (containing 0.1 or 0.8 g CLA/100 g diet, respectively). As expected, the levels of all conjugated diene (CD) fatty acids (CD 18:2 � CD 18:3 � CD 20:3 � CD 20:4) were elevated about 8-fold in the high CLA diet group. However, there was no change in the distribution of CLA and CLA metabo- lites into various lipid fractions due to CLA intake. Unlike linoleic acid or � -linolenic acid, which were distributed mainly in phospholipids, CD 18:2, CD 18:3, and CD 20:3 were incorporated primarily in neutral lipid. Furthermore, the incorporation of all nonconjugated unsaturated fatty acids was not perturbed by CLA. Regardless of the level of CLA in the diet, CD 20:4 was predominantly enriched in phosphatidylserine and phosphatidylinositol. In contrast, arachidonic acid was primarily enriched in phosphatidylcho- line and less so in phosphatidylethanolamine. The above findings may have potential implication regarding the role of CLA in modulating eicosanoid metabolism. — Banni, S., G. Carta, E. Angioni, E. Murru, P. Scanu, M. P. Melis, D. E. Bauman, S. M. Fischer, and C. Ip. Distribution of conjugated linoleic acid and metabolites in different lipid fractions in the rat liver. J. Lipid Res. 2001. 42: 1056-1061