Erythrokinetic study. Morphology of the bone marrow and blood following experimental induction of marrow hypoplasia by cyclophosphamide in laboratory rats.

The morphologic pattern of erythropoiesis suppression and recovery in the bone marrow and blood following cyclophosphamide administration was studied in laboratory rats. The counts of red nucleated cells of the femoral marrow were markedly affected. A striking depopulation of the erythroid pool was observed between the third and fifth day. The minimal compartment transit time of femoral nucleated red cells was calculated. Depletion of marrow red nucleated cells after cyclophosphamide administration and rate or erythropoiesis recovery can be modified by a light-dark rhythm.