Stimulation of the methylation pathway for phosphatidylcholine synthesis in rat lungs by choline deficiency.

The methylation of phosphatidylethanolamine (PE) to form phosphatidylcholine (PC) was investigated using the isolated rat lung perfused with radiolabeled ethanolamine. Lungs from choline-deficient rats showed increased incorporation of radiolabel into PC at 2 h of perfusion. Increased PC synthesis from PE was also observed with lungs from rats fed a lipotrophic (choline plus methionine deficient) diet when methionine was added to the lung perfusate. These results indicate increased activity of the methylation pathway for lung PC synthesis during choline deficiency.