In vivo methotrexate transport in murine Lewis lung tumor

✍ Scribed by K. H. Yang; W. P. Fung; R. J. Lutz; R. L. Dedrick; D. S. Zaharko

• Publisher: John Wiley and Sons
• Year: 1979
• Tongue: English
• Weight: 531 KB
• Volume: 68
• Category: Article
• ISSN: 0022-3549
• DOI: 10.1002/jps.2600680806

✦ Synopsis

Methotrexate uptake by murine Lewis lung tumor was measured in vivo over a wide dose range. The data were analyzed according to a model previously developed for tissues in which methotrexate uptake is rate limited by transport across the cell membrane. Methotrexate transport in this tumor followed Michaelis-Menten kinetics with a rate constant for permeability (k/K) of 0.012 min-1. The methotrexate binding capacity of dihydrofolate reductase in the tumor was not exceeded at any dose studied. A low membrane permeability in conjunction with a high dihydrofolate reductase level explains the resistance of this tumor to methotrexate.