Retention of a dialkylphosphatidylcholine in myelin and other membranes.
We describe an attempt to incorporate a metabolically inert phospholipid analog into animal membranes, especially myelin, in vivo, with the view of eventual long-term membrane modification or membrane engineering. A sonicated suspension of a mixture of [14C]phosphatidylcholine and its dialkyl analog, [3H]  tetradecyloctadecano(1)phosphocholine, was injected into the brain of weanling rats. Samples were counted of whole brain, myelin, liver, and carcass, at intervals from 1 to 63 days, and the composition of the extracted lipid was determined by thin-layer chromatography. Both lipid labels were found to be cleared from the body at similar rates, but while phosphatidylcholine was metabolized within a day, with the label appearing mainly in the phosphatidylethanolamine fraction and in nonpolar lipids, the dialkylphosphatidylcholine remained intact, with retention in myelin of a small but almost constant amount for a month. Ways will have to be found to enhance uptake of the lipids by the brain.
D000818:Animals; D001921:Brain / Q000378:metabolism*; D002250:Carbon Radioisotopes; D008081:Liposomes / Q000378:metabolism; D008099:Liver / Q000378:metabolism*; D008244:Lysophosphatidylcholines; D009186:Myelin Sheath / Q000378:metabolism*; D010713:Phosphatidylcholines / Q000378:metabolism*; D051381:Rats; D013997:Time Factors; D014316:Tritium; D014915:Whole-Body Counting
D002250:Carbon Radioisotopes; D008081:Liposomes; D008244:Lysophosphatidylcholines; D010713:Phosphatidylcholines; D014316:Tritium; C026501:2-tetradecyloctadecano(1)phosphocholine