The lymphoid bone marrow. An experimental model.

: An experimental model is proposed whereby rat bone marrow is converted to a lymphoid-like tissue. A single i.p. injection of hydroxyurea (250 mg/kg body weight) destroys replicating marrow cells in DNA synthesis. Bone marrow erythroblasts constitute the vast majority of cells in cycle under the steady-state of hematopoiesis. Six hours following a single injection of hydroxyurea, selective damage of erythroblasts is noted. The depleted erythroid compartment appears to be replenished by cells of a lymphoid configuration. At 24 hr after injection the erythroid compartment is restored to normal activity. It is suggested that 6 hr after administration of hydroxyurea, lymphoid cells of rat bone marrow may be a source of stem cells for the depleted erythroid compartment.