title: Uptake of [14C]choline and incorporation into lung phospholipid by the isolated perfused rat lung.
abstract: We have used the isolated perfused lung (IPL) preparation from the rat to determine whether uptake of choline from the vascular compartment could limit the rate of synthesis of phosphatidyl-choline (PC). The uptake of choline was rapid and did not saturate at a concentration of 10 mM. The rate of incorporation of choline into phospholipid was saturated above 0.1 mM choline. Whereas, uptake and incorporation were depressed at 4 C, uptake was neither dependent on the extracellular sodium concentration nor inhibited by equimolar concentrations of hemicholinium-3 (HC-3). We could find no evidence that uptake might limit synthesis of lung lecithin and conclude that uptake is either by free diffusion, or by a carrier-mediated process with a very high Km.
mesh_terms: D000818:Animals; D001692:Biological Transport; D002250:Carbon Radioisotopes; D002794:Choline / Q000378:metabolism*; D008168:Lung / Q000378:metabolism*; D008297:Male; D010713:Phosphatidylcholines / Q000378:metabolism*; D051381:Rats
chemical_list: D002250:Carbon Radioisotopes; D010713:Phosphatidylcholines; D002794:Choline