Erythropoietic activity in the serum of mice during postnatal ontogeny

: Some peripheral blood parameters and serum erythropoietic activity were measured in neonatal, young and aged normal mice. There were low level of hemoglobin and red blood cells but increased percentage of reticulocytes and serum erythropoietin level in neonatal mice. The increased serum erythropoietic level were found in aged mice, while peripheral blood parameters were normal. Thus this study demonstrates some changes in erythropoiesis and its regulation during postnatal ontogenesis.