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RESEARCH PRODUCT

Hematopoietins: New Tools in the Treatment of Hematopoietic Insufficiency

subject

description

The number of circulating blood cells and their function are regulated by a variety of peptide hormones, the so-called hematopoietic growth factors (HGFs) or hematopoietins. In a complex regulatory network of stimulating and inhibiting peptide hormones [1], the number of circulating blood cells is kept at a physiological level. Because many of these blood cells have a relatively short half-life, the bone marrow is in a state of constant active proliferation in order to produce the necessary blood cells. For instance, granulocytes are made at a rate of 5 × 107–10 × 107 cells/s. It is unclear whether additional, hematopoietin-independent regulatory mechanisms exist, which might be responsible for the basic production of blood cells. It is well established, however, that under physical stress, for instance during infections, hematopoietins are essential for an adequate hematopoietic response [1]. The nomenclature which has been chosen for hematopoietins can partly be explained historically, in the sense that these factors have been named according to their most prominent biological activity, e.g., the relatively most granulocyte-specific hematopoietin has been named granulocyte-colony-stimulating factor (G-CSF).