Granulopoiesis in anemic Belgrade laboratory (b/b) rats

The aim of this study was to clarify the nature of the abnormalities of granulopoiesis in anemic b/b rats. The size of different granulocytic cell compartments (granulocytic and macrophage precursor cells, proliferative and nonproliferative morphologically recognizable granulocytic cells) in the bone marrow, spleen, and peripheral blood was determined, and activity of granulocytic stimulators (colony-stimulating activities derived from lung-conditioned medium of endotoxin-treated rats and from spleen cells stimulated in vitro with pokeweed mitogen) was investigated. Depressed bone marrow granulopoiesis and expanded granulopoiesis in the spleen, together with the sustained production of granulocytic stimulators, was found in anemic b/b rats. It is suggested that the changes within the bone marrow microenvironment are the essential cause of disturbances of granulopoiesis in anemic b/b rats. The increased proliferation of granulocytic cells in iron-treated b/b rats indicates a role of iron in the cellular proliferation.