Iron incorporation after single and fractionated irradiation of infant mice.

The erythropoiesis in control and irradiated infant mice was investigated on the basis of incorporation of iron into hemopoietic organs and blood. Iron incorporation in bone marrow increased from the second week of life reflecting the maturation of the marrow whereas that in the spleen showed only minor changes. Irradiation of infant mice on day 6 or 9 caused a bone marrow syndrome characterized by an impaired iron incorporation into hemopoietic tissues and blood, by a reduced utilization of serum iron, and particularly by a delayed maturation of the erythropoietic functions of bone marrow. Fractionated irradiation not only had a greater effect on mortality but also caused a more severe and long lasting depression of erythropoiesis than a single dose.