Rescue of folate-deficient erythroblasts by various purine or pyrimidine combinations.

Folate-deficient erythroblasts cultured in FDM made with dialyzed FBS received folic acid or various combinations of purines or pyrimidines at 0 hour as shown below each pair of columns. Viable cell numbers and percentages of apoptosis and cells in the S phase were determined at 32 (■) and 44 (▪) hours. Thymidine and deoxycytidine were added to give concentrations of either 5 or 20 μmol/L as indicated. All purine sources were added to give 60 μmol/L. A, adenosine; G, guanosine; dG, deoxyguanosine; H, hypoxanthine; I, inosine. All results are mean ± SEM for 3 separate experiments.