title: Studies on 18F-labeled pyrimidines III. Biochemical investigation of 18F-labeled pyrimidines and comparison with 3H-deoxythymidine in tumor-bearing rats and mice.
abstract: Metabolic studies of 18F-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 18F-FdUrd and 3H-deoxythymidine (dThd) for tumor detection was compared. In the tumor, 2 h after the injection of the 18F-pyrimidines, 3%-11% and 6%-14% of the 18F was present in the nuclear and microsomal fractions, respectively, and 17%-34% and 19%-24% of the 18F was incorporated into the acid-insoluble and nucleotide fractions, respectively. Of the three 18F-pyrimidines, 18F-FUrd demonstrated the highest incorporation rate, while 18F-FUra showed the lowest incorporation rate. The incorporation in the spleen, small intestine, and liver was less than that in the tumor. 3H-dThd and 18F-FdUrd were injected into the same mice. The 3H-dThd was accumulated in the spleen, small intestine, and tumor, and in these three tissues significant amounts of the 3H were incorporated into acid-insoluble materials. However, the clearance of 18F-FdUrd was slow in the tumor but rapid in the spleen and small intestine. In the autoradiograms of the tumor, 18F and 3H showed a slightly different distribution. Both distribution patterns were unchanged when the soluble materials were rinsed out with perchloric acid. For tumor detection, 18F-FdUrd gives the same information as radio-dThd, and further information can be obtained by positron-emission tomography.
authors.forename: K
authors.initials: K
authors.lastname: Ishiwata
authors.forename: T
authors.initials: T
authors.lastname: Ido
authors.forename: Y
authors.initials: Y
authors.lastname: Abe
authors.forename: T
authors.initials: T
authors.lastname: Matsuzawa
authors.forename: M
authors.initials: M
authors.lastname: Murakami
mesh_terms: D000818:Animals; D005467:Floxuridine; D005472:Fluorouracil; D007504:Iron Radioisotopes / Q000378:metabolism; D008114:Liver Neoplasms, Experimental / Q000000981:diagnostic imaging; D008325:Mammary Neoplasms, Experimental / Q000000981:diagnostic imaging; D051379:Mice; D008809:Mice, Inbred C3H; D009368:Neoplasm Transplantation; D009374:Neoplasms, Experimental / Q000000981:diagnostic imaging*; D011743:Pyrimidines / Q000378:metabolism; D011877:Radionuclide Imaging; D051381:Rats; D013936:Thymidine; D014018:Tissue Distribution; D014316:Tritium; D014529:Uridine / Q000031:analogs & derivatives
chemical_list: D007504:Iron Radioisotopes; D011743:Pyrimidines; D005467:Floxuridine; D014316:Tritium; C001943:5-fluorouridine; D005472:Fluorouracil; D013936:Thymidine; D014529:Uridine