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Simple radiometric assay for methotrexate and other folate antagonists. [Tritium tracer technique]

Journal Article · · J. Lab. Clin. Med.; (United States)
OSTI ID:6295510
A rapid radiometric assay for the folate antagonist MTX, based on the inhibition of chicken liver dihydrofolate reductase activity, has been developed. In the system the inhibition by MTX of the reduction of tritiated FH/sub 2/ is standardized and used to quantitate this antagonist in plasma of subjects receiving high-dose MTX therapy. The assay permits the detection of plasma MTX levels to 5 x 10/sup -9/M with a coefficient of variation of 15%. The predominating circulating folate, 5 methyltetrahydrofolate, or the rescue agent leucovorin (5 formyltetrahydrofolate) do not significantly interfere with the assay at concentrations attainable with current rescue programs. Analyses of multiple plasma samples with the present assay show close agreement with the competitive protein-binding assay.
OSTI ID:
6295510
Journal Information:
J. Lab. Clin. Med.; (United States), Journal Name: J. Lab. Clin. Med.; (United States) Vol. 93:3; ISSN JLCMA
Country of Publication:
United States
Language:
English