Production of erythroid cells in phenylhydrazine-treatedRana catesbeiana tadpoles

The production of red blood cells in Rana catesbeiana tadpoles was examined following the induction of complete anemia by phenylhydrazine treatment. Initial destruction of circulating red blood cells is followed in several days by the appearance of proerythroblasts and basophilic erythroblasts first in the tadpole liver and subsequently in the peripheral circulation. These continue to increase greatly in number and to mature in subsequent days. By 16 days after the beginning of phenylhydrazine treatment, a population of uniformly immature erythrocytes (polychromatophilic erythroblasts) is evident in the peripheral circulation. All these cells contain hemoglobin, and many well hemoglobinized cells are undergoing mitosis. By ultrastructural criteria, this latter cell type contains an abundance of polyribosomes, mitochondria, and other cytoplasmic organelles. Heterochromatization of the nucleus appears distinctly less than in controls. Polyribosomes could be isolated from these erythroid cells only after the removal of leukocytes by filtration of peripheral blood through lamb's wool columns; polyribosomal profiles on sucrose gradients demonstrate that erythroid cells produced in response to phenylhydrazine treatment possess high synthetic activity. In addition, they contain hemoglobin identical to that found in normal tadpole erythrocytes.