Studies on fluorinated pyrimidines. III. The metabolism of 5-fluorouracil-2-C14 and 5-fluoroorotic-2-C14 acid in vivo.

As one of the initial steps towards the determi nation of the metabolism and mechanism of action of fluorinated pyrimidines, 5-fluorouracil and 5fluoroorotic acid were labeled with radiocarbon in the 2-carbon atom. We have previously reported briefly that fluorouracil is incorporated, as such, into the combined nucleic acids of mouse liver, spleen, and Ehrlich ascites cells (9). The present report describes the distribution, excretion, and metabolism of these compounds in mice, with and without tumors, and in a human cancer patient.