Effects of Radiation on Radioiron Uptake in Mouse Erythrocytes in vitro

The in vitro iron uptake by erythrocytes was examined as an indicator of radiation effects on erythropoiesis in mice. Erythrocyte suspensions were incubated with 59Fe, previously bound to serum for 3 hours at 37℃. The changes of the iron uptake within 48 hours following Xirradiation of 25 R and 50 R showed biphasic patterns. The reduction of the uptake at 18-20 hours after irradiation correlated exponentially with the exposure doses from 25 R to 200 R. In animals irradiated with 200 R, the recovery from the radiation-induced depression of the iron uptake by the in vitro method was delayed by two days from that estimated by the in vivo iron uptake studies. Since the in vitro uptake is mostly due to young reticulocytes present in the erythrocyte suspension, the delay of two days in recovery is likely to be attributed to the time required for erythroblasts in bone marrow and spleen to mature and be released to blood as reticulocytes. The in vitro iron uptake reflects the reticulocyte counts, and can be a simple and reliable indicator for radiation-induced disturbances of erythropoiesis.