Fatty acid esterification and chylomicron formation during fat absorption in rat: III. Positional relations in triglycerides and lecithin

Abstract

Chylomicron triglyceride and lecithin obtained after feeding mixtures of three or four free fatty acids to rats were hydrolyzed using pancreatic lipase and phospholipase A respectively. The distribution of fatty acid mass and radioactivity in the substrate materials and in the cleavage products was determined by gasȓliquid chromatography.The incorporation of exogenous (labeled) fatty acids into different positions was nearly random in the triglycerides but markedly nonrandom in lecithin where saturated acids, especially stearic acid, were predominantly esterified at the α′-position and polyunsaturated fatty acids at the Β-position.Specific radioactivity measurements were interpreted as showing greater than random amounts of endogenous (unlabeled) palmitic acid on the α′-position of lecithin and, to a small extent, of endogenous linoleic acid on the Β-position of triglyceride.

Keywords

• chylomicron
• fatty acids
• exogenous (C14)
• endogenous
• incorporation
• triglyceride