Composition for determining pyrimidine metabolizing activity

摘要

The present invention provide a method for assessing the sensitivity to a pyrimidine drug such as 5-FU which is degraded in the pyrimidine metabolic pathway, specifically in vivo pyrimidine metabolizing activity, of an individual subject; and a preparation useful for the assessment. The present invention can be carried out by: administering a preparation comprising as an active ingredient a pyrimidine compound or its metabolite which acts as a substrate for a pyrimidine metabolizing enzyme, in which compound or metabolite at least one of C, O and N is labeled with an isotope; and assessing in vivo pyrimidine metabolizing activity based on the amount of excreted metabolite.