Possible Interaction: Fluorouracil and Inosine

“In a variety of systems either inosine or deoxyinosine have been shown to increase growth inhibition by 5FU (3,4,5) and to enhance antitumor activity (6).”

“In the absence of oxipurinol, inosine increased FUra uptake into total RNA of Jensen sarcoma by as much as 57%, compared to inosine-free controls, but markedly inhibited FUra uptake into total RNA of the small intestine.(ABSTRACT TRUNCATED AT 250 WORDS)”

“In the presence of sufficient oxipurinol to induce inhibition at approximately these levels, inosine failed to stimulate FUra uptake into intestinal RNA, ….1 mM inosine restored FUra uptake into Jensen sarcoma RNA to the level found in oxipurinol-free controls, and 0.5 mM inosine … FUra uptake 29% … controls.”

“Continuous exposure of JT cells to inosine after a 1-h uptake of FUra was reported earlier to potentiate drug efficacy 5-fold.”

“Treatment of cultures by both modes of inosine exposure that enhance FUra cytotoxicity resulted in a 15.8-fold potentiation of the latter.”

“… FUra alone had no effect on … combination of FUra plus inosine altered the levels of ribose 1-phosphate but not 5-phosphoribosyl 1-pyrophosphate, altered the maturation of precursor ribosomal … of 18S RNA, altered the methylation of the ribosomal RNA, and caused inhibition of the growth of these cells.”

“The incorporation of 5-fluorouracil-2 -14C into RNA also is greatly increased by inosine.”