Monitoring the administration of methotrexate in antimetabolite therapy.
An enzymatic method for the measurement of methotrexate (MTX) in serum is presented in which the inhibition of the enzyme dihydrofolate reductase by MTX is measured. Reduction of the substrate dihydrofolate by the enzyme and cofactor NADPH is lessened in direct proportion to the amount of MTX present. Measurements can be made in the "therapeutic range" of MTX which corresponds to the 10(-7) to 10(-8) M concentration of MTX in serum.
D005492:Folic Acid / Q000378:metabolism; D005493:Folic Acid Antagonists; D006801:Humans; D008623:Mercaptoethanol; D008722:Methods; D008727:Methotrexate / Q000008:administration & dosage / Q000097:blood* / Q000627:therapeutic use; D009249:NADP
D005493:Folic Acid Antagonists; D009249:NADP; D008623:Mercaptoethanol; D005492:Folic Acid; D008727:Methotrexate