Differences in some erythroid regulatory parameters between two inbred mouse strains

Normal erythropoiesis in inbred CBA/Tr x CBA/Tr mice is shown to be associated with higher rates of red blood cell production and destruction than in age-matched, but significantly larger, C57Bl6/Tr x C57Bl6/Tr mice. As expected from these observations, serum Ep titers were significantly higher in the CBA/Tr mice than in the C57Bl6/Tr mice. These differences, which appear to result from variations in the operating point for erythropoiesis, can explain the different in vitro erythropoietin sensitivities of hematopoietic tissue from these two mouse strains.