INTESTINAL ABSORPTION OF 1,2- AND 1,3-DIALKYL GLYCEROL ETHERS AND OF DIETHER PHOSPHOLIPIDS

1. 1. Labeled 1,2- and 1,3-dialkyl glycerol ethers and 1,2-dialkyl analogs of phosphatidyl choline, phosphatidyl ethanolamine and phosphatidic acid were used as model substances for the corresponding fatty acid ester derivatives to study their intestinal absorption and incorporation into lymph lipids. 2. 2. The substances were fed to intact and lymph cannulated rats. Lipids extracted from lymph and organs were analyzed for total activity and distribution of activity between different lipid classes. 3. 3. The amount of dialkyl glycerol ethers absorbed depends on the chain length (8-10%) for the long chain vs. 52% for the dioctyl derivative), but not on the position or degree of saturation of the alkyl moieties. The rate of esterification with fatty acids during passage through the gut, however, is quite different for the 1,2 and 1,3 isomer, the 1,2 isomer being the favored substrate in this reaction. Only traces of intact diether phospholipids are incorporated into lymph lipids. 4. 4. The possibility of ω-oxidation as the pathway for the degradation of the 1,2-dialkyl glycerol ethers is discussed. © 1969.