Reticulocyte Generation Time and Rate of Discharge from the Marrow

Identity of Erythroblast Precursors in Bone Marrow

“…Although the stimulus produced a measurable effect on the marrow 24 h after bleeding [8], the proliferation of erythroblasts present in the marrow at that time was apparently not affected. The trends shown in figure 2 seem to represent a stream of cells entering the erythroid compartment during the period of stimulation with a significantly increased rate of proliferation.…”

“…The total erythroid output by the marrow may be determined from the knowledge of (a) the bone marrow [16] and blood volume [17], (b) the daily physiological loss in red cells [18], (c) the increase in the red cell count [8], (d) the number of marrow reticulocytes [8], and (e) the number of erythro-blasts. During the first 3 days following bleeding, 7 X 10* cells were produced by the marrow, splenic red cell output at this time being negligible.…”

“…Polycythemia and erythropoietically suppressed bone marrow was produced in guinea pigs using the procedure described previously [8]. Restimulation of erythropoiesis was effected by bleeding on the 9th day of rebound while unbled polycythemic guinea pigs served as controls.…”

“…Restimulation of erythropoiesis was effected by bleeding on the 9th day of rebound while unbled polycythemic guinea pigs served as controls. Changes in nucleated bone marrow cells were studied in the same scries of stimulated and control guinea pigs as for which the blood and marrow reticulocyte data have already been presented [8].…”

“…Differential counts were also performed classifying 500 leukocytes in each animal. Red cell parameters and changes in the spleen have been reported separately [8]. The weight of the suprarenal glands was recorded in the stimulated animals.…”