Erythrocyte Fe59 Uptake as a Function of Bone Marrow Dose Injected in Lethally Irradiated Mice

Abstract

Abstract The relation between bone marrow cell dose and 24-hour erythrocyte Fe59 uptake has been established in lethally irradiated mice. Erythrocyte Fe59 uptake is a function of the dose of bone marrow cells and of the time after irradiation at which Fe59 is injected. By choosing appropriate bone marrow doses and times of Fe59 injection, the range of cell doses between 5 x 105 and 2 x 107 has been explored. The relation between cell dose and Fe59 uptake is linear for Fe59 uptakes between 0 to 30 per cent. The steepest line relating Fe59 uptake to cell dose is that obtained when Fe59 was injected at day 9 and covers the range of 5 X 104 to 5 X 105 cells. The curve obtained when iron is injected on day 5 is much flatter and covers the range of 1 x 106 to 2 x 107 cells. Erythropoiesis stimulating factor (ESF) in doses that stimulate erythrocyte Fe59 uptake in normal mice has no effect in irradiated, bone marrow-treated mice. Homologous marrow is slightly less effective, and rat bone marrow markedly (∼ 100 times) less effective in promoting recovery of erythropoieis. The erythrocyte Fe59 uptake of mice preimmunized with homologous or rat marrow before irradiation is much lower than that of nonpreimmunized animals.