Nucleic Acids of Rabbit Reticulocytes

1. The concentration of acid soluble phosphorus, lipid phosphorus and nucleic acid phosphorus was determined in the red cells and polymorphonuclear leukocytes of the rabbit. The concentration of acid soluble phosphorus was of the same order in both types of cells, but there was more lipid phosphorus and nucleic acid phosphorus in the polymorphonuclear leukocytes than in the red cell. Over 80 per cent of the nucleic acid in white cells was of the desoxypentose type.

2. Immature cells were produced in the peripheral blood stream of rabbits either by the administration of phenylhydrazine or by successive bleedings. Either treatment caused a fall in the concentration of hemoglobin, the red cell count and the hematocrit with an increase in the mean corpuscular hemoglobin. There was also an increase in the concentration of acid soluble phosphorus and lipid phosphorus and a great increase in the concentration of nucleic acid phosphorus which was coincident with the increase in number of immature cells as judged by the reticulocyte count. Almost all of the excess nucleic acid was of the pentose type.

3. The basophilia of the immature cells disappeared after treatment with ribonuclease or after hydrolysis with normal hydrochloric acid. Desoxyribonuclease was without effect.

4. These results suggest that the basophilic substance of the immature rabbit red cell, and presumably the reticulum of the reticulocyte, is of cytoplasmic rather than nuclear origin.