Abstract des Autors

Erythropoietin (EPO) is a glycoprotein hormone which is required for maintenance, proliferation and differentiation of the stem cells that produce erythrocytes. lt is a member of cytokine family, a group of proteins involved in regulation of cell growth and differentiation. As with other cytokines, the activity of EPO is mediated by formation of extracellular complexes, which results in the transmission of a signal to the interior of the cell. In the case of EPO the level of the circulatory erythrocytes is regulated by stimulating the maturation of late erythroid progenitor cells into proerythroblasts. By this mechanism the hormone stimulates production of red blood cells. Administration of EPO increases reticulocyte counts, haemoglobin levels (from 15 to 54%) and haematocrit (from 17 to 60%) in a dose-proportional manner after intravenous administration. Interestingly, hematocrit (HCT) increased more rapidly after s.c. administration compared to patients who received EPO intravenously, and may last about two to six weeks. lt has been reported that natural level of serum EPO increased after exercise but the mean hematocrit values were not changed significantly. Administration of EPO is associated with a significant decrease in serum ferritin (by 74%) which might be reversed with i.v. iron supplementation. Verf.-Referat