engleski

Effects of short term fat-free diet on fatty acid composition of liver phospholipids

The elucidation of phospholipids molecular species composition provides important information concerning membrane physical and biological properties. In this work the influence of fat free diet on the fatty acid composition and the arrangement on the glycerol backbone of rat liver phospholipids was studied. Animals were fed for two weeks with a fat free diet (FFD) isoenergetic with control diet (CD). Total lipids were extracted from liver homogenate and fatty acid composition was analyzed by using gas chromatography. Phospholipid classes were separated by column and high performance thin layer chromatography and, after treatment with phospholipase A2, composition of fatty acids linked to sn-1 and sn-2 position of glycerolipids was analyzed. In total lipids, a significant decrease in the 18:2, 20:4 and 20:5 species was counterbalanced by an enhancement in the 16:0, 16:1, 18:1 and 20:2 species. In contrast to total lipids, changes in the fatty acid composition and positional distribution of the three phosphoglyceride classes analyzed (phosphatidylcholine (PC), phosphatidylethanolamine (PE) and phosphatidylinositol + phosphatidylserine (PI+PS)), induced by fat free diet, were of less importance. The global fatty acid distribution was not affected. On sn-1 position of PC and PI+PS classes, the minor fall in 16:0 and 18:0 species was detected, with concomitant increase in 18:1, 20:2, and 22:6 species. Changes were even less pronounced on sn-2 position, suggesting that subtle modulations in fatty acid composition tend to compensate essential fatty acid deficiency.

fat-free diet; fatty acid; phospholipid; rat; liver

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