Effects of 5-fluorouridine on modified nucleosides in mouse liver transfer RNA

Administration of the pyrimidine antimetabolite, 5-fluorouridine, to mice was found to cause a marked specific reduction of the amounts of 5-methyluridine, pseudouridine, and dihydrouridine but not of 3-(3-amino-3-carboxypropyl)uridine in tRNA from the livers of the treated animals. The data presented indicate that this effect is not simply due to the incorporation of 5-fluorouridine into tRNA; the drug appears to interfere directly with the enzymic reactions involved in the modification of the 5-position of uridine. 5-Fluorouridine was found to have no effect on the modification of adenosine, guanosine, and cytidine in mouse liver tRNA.