Comparison of the Sensitivity of Hematopoietic Colony-Forming Cells in Different Proliferative States to 5-Fluorouracil2

Abstract

Dose-survival curves were obtained for normal hematopoietic colony-forming cells, hematopoietic colony-forming cells in both exponential and transitional phase of growth, and lymphoma colony-forming cells—all in the femoral marrows of mice after exposure for 1 hour to 5-fluorouracil (5-FU). The rapidly proliferating, exponential phase cells, and slowly proliferating, transitional phase cells were obtained from the femoral marrows of mice which had been irradiated and then given 5 × 10⁶ normal marrow cells 7 and 21 days earlier, respectively. The four survival curves were exponential in shape. The slopes of the curves for the normal and the transitional phase cells and the lymphoma and exponential phase cells were similar; however, the lymphoma and the rapidly proliferating marrow cells were 6 times as sensitive to 5-FU as were the normal marrow cells. The results support the suggestion that the difference in the sensitivity of normal hematopoietic and rapidly proliferating colony-forming cells to 5-FU can be explained on the basis of differences between the proliferative states of the two cell populations.