title: Use of tritiated 3-O-methyl-D-glucose for studies of membrane transport. Caveat.
abstract: Tritiated 3-O-methyl-D-glucose has many useful attributes as a model substance for studies of the transport of glucose across cell membranes. However, preparations of high specific radioactivity can decompose within a few months, producing radioactive impurities that can cause a several-fold increase in the apparent rate of sugar transport. In our investigation radioactive contaminants entered frog skeletal muscle cells by free diffusion rather than by facilitated transport. Much of the contaminating radioactive material could be removed by evaporating the solvent and redissolving the sugar. Tritiated sugar samples that had a specific activity below 0.1 Ci/mmol remained stable and suitable for transport measurements after several years of storage at -20 degrees C. In order to evaluate the suitability of a given tritiated preparation of sugar for transport measurements, it is recommended that its behavior be compared with that of a stable reference standard of low specific activity.
mesh_terms: D019325:3-O-Methylglucose; D000818:Animals; D001692:Biological Transport; D002462:Cell Membrane / Q000378:metabolism*; D005260:Female; D007700:Kinetics; D008757:Methylglucosides / Q000378:metabolism; D008759:Methylglycosides; D009132:Muscles / Q000378:metabolism; D011894:Rana pipiens; D012508:Sarcolemma / Q000378:metabolism; D014316:Tritium
chemical_list: D008757:Methylglucosides; D008759:Methylglycosides; D014316:Tritium; D019325:3-O-Methylglucose