Changes in 59Fe Uptake into Erythrocytes and Chemically Separated Heme Fractions of Spleen and Femoral Bone Marrow after Irradiation with X-rays at Different Doses in OK-432 Treated Mice.

The radiation dose range in which OK-432 would promote the recovery of radiation-impaired erythropoiesis was investigated.C57BL/6J male mice were injected with a single dose of 5 KE of OK-4321 h before or 1 h after irradiation with X-rays.Erythropoietic activity was measured by 59Fe incorporation into circulating erythrocytes and the chemically separated heme iron fraction of erythropoietic tissues.When irradiated with 94. 5 cGy to 567 cGy of X-rays the uptake of 59Fe into circulating erythrocytes was promoted within 20 days after irradiation by the treatment with OK-432.Treatment with OK-432 1 h before otherwise lethal irradiation with 662 cGy significantly enhanced the 59Fe uptake into erythrocytes.These results demonstrate that OK-432 stimulates erythropoietic recovery in sub-lethally and lethally irradiated mice.At long time intervals following irradiation with 567 cGy or 662 cGy of X-rays, the 59Fe uptake into erythrocytes in the OK-432-treated group was quite similar to the corresponding non-irradiated controls.Further studies to ascertain whether OK-432 can be used as a radioprotective agent are currently in progress.