Cytomorphology and behavior of late bone marrow and peripheral blood erythroid cells in experimental hemolytic anemia

Hemoglobin biosynthesis in rabbits with phenylhydrazine-induced anemia has been morphologically studied, comparing late bone marrow with peripheral blood erythroid cells of the same maturing degree. They were analysed through thin sections, as to their organelle type content and behavior regarding iron incorporation. Hemosomes are organelles taken as sites of final hemoglobin biosynthesis, and the ratio between their mean number in blood reticulocyte sections and that in late marrow erythroid cell sections reach about 10: 1. Late marrow erythroid cells contain practically twice the mean number of mitochondria in relation to this mean number in blood reticulocytes. Mitochondria are considered as potential acting entities for hemoglobin biosynthesis, since they participate in hemosome formation. Iron incorporation activity increases more than twice in peripheral blood reticulocytes, as compared to the mean in late marrow erythroid cells. These analytical results suggest that an enhancement of hemoglobin synthesis activity occurs when erythroid cells enter the peripheral blood.