title: Phosphatidylcholine metabolism in ischemic and hypoxic hearts.
abstract: The rates of phosphatidylcholine biosynthesis in the isolated hamster hearts under ischemic and hypoxic conditions were examined. Global ischemia was produced by perfusion of the heart with a reduced flow, whereas hypoxia was produced by perfusion with a N2-saturated buffer. A 51% reduction in the biosynthesis of phosphatidylcholine was observed in the ischemic heart. The reduction was caused by a severe decrease in ATP level which resulted in a diminished conversion of choline into phosphocholine. A 22% reduction in the biosynthetic rate of phosphatidylcholine was also detected in the hypoxic heart. The reduction was caused by a diminished level of CTP which resulted in a decreased conversion of phosphocholine to CDP-choline. No compensatory mechanism was triggered during ischemia, but the CTP: phosphocholine cytidylyltransferase activity was enhanced in the hypoxic heart. Our results demonstrate the possible rate-limiting role of choline kinase and reconfirm the regulatory role of the cytidylyltransferase in the biosynthesis of phosphatidylcholine.
authors.affiliation: Department of Biochemistry & Molecular Biology, Faculty of Medicine, University of Manitoba, Winnipeg, Canada.
authors.forename: P C
authors.initials: PC
authors.lastname: Choy
authors.forename: M
authors.initials: M
authors.lastname: Chan
authors.forename: G
authors.initials: G
authors.lastname: Hatch
authors.forename: R Y
authors.initials: RY
authors.lastname: Man
mesh_terms: D000255:Adenosine Triphosphate / Q000378:metabolism; D000818:Animals; D001692:Biological Transport; D015687:Cell Hypoxia; D002794:Choline / Q000378:metabolism; D002797:Choline Kinase / Q000378:metabolism; D019916:Choline-Phosphate Cytidylyltransferase; D006224:Cricetinae; D003566:Cytidine Diphosphate Choline / Q000378:metabolism; D003570:Cytidine Triphosphate / Q000378:metabolism; D008647:Mesocricetus; D017202:Myocardial Ischemia / Q000378:metabolism*; D009713:Nucleotidyltransferases / Q000378:metabolism; D010713:Phosphatidylcholines / Q000378:metabolism*; D010767:Phosphorylcholine / Q000378:metabolism
chemical_list: D010713:Phosphatidylcholines; D010767:Phosphorylcholine; D003566:Cytidine Diphosphate Choline; D003570:Cytidine Triphosphate; D000255:Adenosine Triphosphate; D002797:Choline Kinase; D009713:Nucleotidyltransferases; D019916:Choline-Phosphate Cytidylyltransferase; D002794:Choline