Reticulocyte Formation Research Articles

(2??5?) Oligoadenylate synthetase in the maturation of rabbit reticulocytes

The (2'-5') oligoadenylate synthetase normally found in interferon-treated cells has also been detected in considerable amounts in normal rabbit reticulocytes not exposed to interferon. The activity of this enzyme has been followed during the development of the reticulocytes to erythrocytes. A high level was found just after the formation of reticulocytes and this activity decayed with a half-life of about 3 days. In lymphocytes the (2'-5') oligoadenylate synthetase was found to stay at a constant level, which indicates the absence of interferon in the plasma.

Study of maturation of membrane transport function in red blood cells by X-ray microanalysis.

Red blood cells of certain species of animals, such as dogs and cats contain low potassium and high sodium, whereas the erythropoietic stem cells giving rise to these cells are of high potassium type. This paper examines the sequence of membrane transport changes during erythropoiesis by analyzing the K, Na and Fe in single bone marrow cells, reticulocytes and mature red blood cells with X-ray microanalysis. The relationship between K/Na ratios and Fe/(K + Na), which is analogous to hemoglobin concentration, gives an index of maturation stage. The relationships between K/Na and Fe/(K + Na) in the marrow cells of normal adult dog and those of a phenylhydrazine-injected dog with accelerated erythropoiesis show that the modification of cation composition occurs after the initiation of hemoglobin synthesis but before its completion. Similar relationships in the reticulocytes obtained from phenylhydrazine-injected dogs as well as from newborn dogs show a consistent decrease in K/Na with increased Hb, indicating a drastic change in cation composition during the maturation of the reticulocytes. Therefore the modification in membrane transport function must have occurred before or during the formation of reticulocytes.

Postnatal regulation of oxygen delivery: Control of erythropoiesis following birth in dogs

Blood hemoglobin concentration decreases during the first postnatal month of canine life. Red cell production, as indicated by reticulacyte levels, decreases following birth and does not incease until the second postnatal month. Bleeding and transfusion studies were performed to determine if the canine erythropoietic system is defective during this early neonatal period or is operating at a less than maximal rate due to adequate oxygen delivery to those tissue which regulate erythropoiesis. There is no fundamental defect in the erythropoietic system since bleeding stimulates reticulocyte formation during the first postnatal month. Conversely, the reticulocytosis that occurs during the second postnatal month was suppressed when oxygen delivery was increased by a red cell transfussion. We conclude that adequate oxygen delivery following birth causes a reduction in red cell production and results in postnatal anema. Due to increasing metabolic oxygen requirements of continued growth, the blood oxygen delivery becomes inadequate by the second postnatal month and red cell production is stimulated.