Diacylglycerol synthesized in vitro from sn-glycerol 3-phosphate and the endogenous diacylglycerol are different substrate pools for the biosynthesis of phosphatidylcholine in rat lung microsomes.
In microsomes of rat lung, labeled diacylglycerol was synthesized from sn-[3H]glycerol 3-phosphate, which had been added, and from the endogenous free fatty acids. In these microsomes containing biosynthesized [3H]diacylglycerol as well as endogenous nonlabeled diacylglycerol, the synthesis of phosphatidylcholine was measured from added [14C]CDPcholine. The incorporation of [methyl-14C]choline and of [3H]diacylglycerol into phosphatidylcholine showed an entirely different progress in the time-course of incubation. The 14C label of phosphatidylcholine increased continuously, whereas the 3H label remained constant after 2 min up to the end of the incubation period of 20 min. From this result we concluded that the diacylglycerols, synthesized in vitro from glycerol 3-phosphate over an incubation period of 20 min, constitute a separate substrate pool for the biosynthesis of phosphatidylcholine, and are not mixed with the endogenous diacylglycerol pool.
D000818:Animals; D002250:Carbon Radioisotopes; D003566:Cytidine Diphosphate Choline / Q000378:metabolism; D004075:Diglycerides / Q000096:biosynthesis* / Q000378:metabolism; D005989:Glycerides / Q000096:biosynthesis*; D005994:Glycerophosphates / Q000378:metabolism*; D007700:Kinetics; D008168:Lung / Q000378:metabolism*; D008861:Microsomes / Q000378:metabolism*; D010713:Phosphatidylcholines / Q000096:biosynthesis*; D051381:Rats; D014316:Tritium
D002250:Carbon Radioisotopes; D004075:Diglycerides; D005989:Glycerides; D005994:Glycerophosphates; D010713:Phosphatidylcholines; D014316:Tritium; D003566:Cytidine Diphosphate Choline; C029620:alpha-glycerophosphoric acid