| Abstrakt: |
Metabolic studies of F-labeled 5-fluoro-2′-deoxyuridine (FdUrd), 5-fluorouridine(FUrd) and 5-fluorouracil (FUra) were performed in tumor-bearing rats and mice. Also, the usefulness of F-FdUrd and H-deoxythymidine (dThd) for tumor detection was compared. In the tumor, 2 h after the injection of the F-pyrimidines, 3%-11% and 6%-14% of the F was present in the nuclear and microsomal fractions, respectively, and 17%-34% and 19%-24% of the F was incorporated into the acid-insoluble and nucleotide fractions, respectively. Of the three F-pyrimidines, F-FUrd demonstrated the highest incorporation rate, while F-FUra showed the lowest incorporation rate. The incorporation in the spleen, small intestine, and liver was less than that in the tumor. H-dThd and F-FdUrd were injected into the same mice. The H-dThd was accumulated in the spleen, small intestine, and tumor, and in these three tissues significant amounts of the H were incorporated into acid-insoluble materials. However, the clearance of F-FdUrd was slow in the tumor but rapid in the spleen and small intestine. In the autoradiograms of the tumor, F and H showed a slightly different distribution. Both distribution patterns were unchanged when the soluble materials were rinsed out with perchloric acid. For tumor detection, F-FdUrd gives the same information as radio-dThd, and further information can be obtained by positron-emission tomography. [ABSTRACT FROM AUTHOR] |
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