Changes in the Composition of Fatty Chains of Diacyl, Alkylacyl and Alkenylacyl Ethanolamine and Choline Phosphoglycerides During the Development of Chick Heart Ventricular Cells. High Accumulation of 22-carbon Fatty Acid in Ether Phospholipids

The phospholipids of embryonic chick ventricular cells were analysed at various developmental stages with respect to the composition of alkylacyl, alkenylacyl and diacyl ethanolamine and choline phosphoglycerides and for the fatty chain composition of these lipid classes. The percentage of alkylacyl and alkenylacyl choline phosphoglycerides increased in the course of the development. The fatty chain composition of ether-linked phosphoglycerides was significantly different from that of the diacyl compound. In general, both ether choline and ethanolamine phosphoglycerides consisted of a significantly higher percentage of 22-carbon fatty chains, such as 22:4, 22:5 and 22:6, compared to that of the diacyl compounds, throughout the earlier stage of development. During development, there was a dramatic increase of 20:4 and a decrease of 22:6, mainly in total ethanolamine phosphoglycerides but also in choline phosphoglycerides. A particularly significant decrease of 22:6 was found with diacyl ethanolamine phosphoglycerides. When 14C-labeled 22:4 and 3H-labeled 20:4 were incorporated into the ethanolamine and choline phosphoglycerides of ventricles in vitro, it was observed that 22:4 was mainly associated with ether phospholipids, especially the ethanolamine alkyl ether phospholipids, suggesting that there is a high selectivity of 22-carbon fatty acid to ether phospholipids during the synthesis of these compounds.