Kinetics and cellularity of erythroblasts in the growing rat.

Parameters of recognizable erythroid cell proliferation were measured in four groups of normal rats weighing 50, 100, 150 and 300 g in order to provide a comprehensive set of data suitable for a re-investigation of erythropoietic models. Total erythroblast cellularity was measured by the 59Fe technique, DNA synthesis time by quantitative 14C-autoradiography, and the erythrocyte production rate was derived from the increase with time of the erythrocyte labelling index after repeated injections of 3H-leucine. Furthermore, the relative erythroblast density was determined in the various morphological compartments.