Effect of dietary linoleic acid content on the distribution of phosphatidylcholine molecular species in rat plasma

Abstract

The effect of dietary linoleic acid on the profiles of phosphatidylcholine molecular species in rat plasma was investigated. On changing from an essential fatty acid-deficient state to an essential fatty acid sufficient state, the levels of molecular species containing 18:1 and 20:3n−9 were decreased, whereas those containing 18:2n−6 and 20:4n−6 were increased. However, the decrease was greater in the molecular species containing 20:3n−9 than in those containing 18:1, and the increase was greater in the molecular species containing 20:4n−6 than in those containing 18:2n−6. In rats fed the essential fatty acid deficient diet (containing 0.001 g/kg diet of linoleic acid), the major molecular species in plasma phosphatidylcholine was 16:0–8:1 and most of the molecular species have the total carbon chain length around 34. In rats fed the essential sufficient diet (containing 2.4 g/kg diet of linoleic acid), the major phosphatidylcholine molecular species was 18:0–20:4n−6, and most species had the total carbon chain length around 38. The changes of the molecular species profiles indicated that the metabolism of 18:1 to 20:3n−9 which was active in the essential fatty acid deficient rats was replaced with that of 18:2n−6 to 20:4n−6 in the essential fatty acid sufficient state.