Quantitative measurement of erythropoiesis in the dog

The quantitative measurement of erythropoiesis requires the simultaneous determination of total red cell volume, rate of production of red cells and the red cell life span. The total red cell volume was measured with autologous Cr51-labeled red cells, the rate of production of red cells from the rate of disappearance of radioiron from the plasma and uptake by red cells, the red cell life span with C14-labeled glycine and the apparent red cell survival T1/2 with Cr51. The average total red cell volume of the dogs studied was 38.6 cc/kg; the plasma radioiron T1/2 was 66 minutes; the red cell radio-iron uptake was 80%; the serum iron was 102 µg/100 cc, and the plasma volume calculated from the peripheral hematocrit and total red cell volume was 46 cc/kg, and from the extrapolation to t0 of the radioiron disappearance was 48 cc/kg. From these figures the plasma iron turnover was calculated to be 0.63 mg/kg/day and the red cell iron renewal rate 1.26%/day. The average red cell life span was 108 days; the average apparent T1/2 of Cr51 red cell survival was 24.3 days; the average elution rate of Cr51 was 1.77%/day.