[Erythropoietin: from gene to therapeutic agent].

Erythropoietin is a hormone whose production is stimulated by all forms of oxygen deficiency. The main production takes place in specialized fibroblasts in the kidney of adults and in liver cells during the fetal and neonatal period. The most important function of the hormone can be derived from its name: It stimulates erythropoiesis in the bone marrow and thus controls O2-capacity of blood. A thoroughly controlled feedback-mechanism between oxygen-supply erythropoietin release and renewal of erythrocytes provides for a constant level of erythrocytes in blood. This feedback mechanism is disturbed by chronic renal diseases, chronic inflammations and also in premature infants. Recombinant human erythropoietin is used as hormonal substitute in order to correct diverse types of anemia and may also be used in the context of re-transfusions.