Possible involvement of L-glycero-phosphoryl-ethanolamine in the phospholipid methylation pathway.

It is usually accepted that GPEtn is only an intermediate in glycerophospholipid degradation. However, some years ago J. P. Infante published a review-hypothesis concerning the possible involvement of GPEtn and GPCho in the biosynthesis of acyl-specific glycerophospholipids in mammalian tissues. This paper reports the results obtained by incubating brain cortex slices in the presence of labeled GPEtn. GPEtn enters the cells and the radioactivity of the precursor is found in both PE and PC. When these results were compared with those obtained by incubating brain slices in the presence of 3H-Etn, a significantly higher amount of radioactivity was found in PC, mainly after short incubations in the presence of low concentrations of the precursors. The slopes of the methylated forms of PE further underline the above differences found by comparing the results obtained with the two precursors. The results presented in this paper suggest a possible role of GPEtn in phospholipid biosynthesis and methylation pathway of PE.