Erythropoietin is a glycoprotein that is produced primarily in the kidneys in adults and, to a lesser extent, in the liver. It behaves like a hormone, regulating the level of erythropoiesis, and keeping the RBC count within a narrow rangeIt is used widely in medicine as a treatment for a number of serious illnesses, ranging from types of anaemia, to the treatment of certain types of cancer, and also in the battle against AIDS. Unfortunately certain athletes, who will do anything to win, have realised its ergogenic benefits, and also the severity of its misuse. Regulation of Erythropoietin Production.In the kidneys, erythropoietin is produced in fibroblastoid interstitial cells in the inner renal cortex, while in the liver, the hormone is produced by both hepatocytes and interstitial fibroblastoid cells. Although a variety of growth factors influence erythroid progenitor cell proliferation, erythropoietin is the most important, and erythropoiesis cannot continue in its absence.Among the haematopoietic growth factors, erythropoietin is one of few that behaves like a hormone. It is unique because its production, under normal circumstances, is controlled solely at the level of its gene, by tissue hypoxia and not by the absolute number of circulating erythrocytes. Hypoxia is the sole physiologic stimulus for erythropoietin production, and an excess of oxygen suppresses its production but never completely. Some facts about EPO. (Birchard K, Lancet 1998; 352: 42.)Neither age nor gender influences the plasma erythropoietin level, Plasma erythropoietin is constant in a given individual, Erythropoietin production is regulated at the level of its gene, Hypoxia is the only physiologic stimulus for erythropoietin production, There are no pre-formed stores of erythropoietin,There is only one form of circulating erythropoietinFollowing production in the kidneys and liver, erythropoietin travels to the bone marrow to interact with specific hae...
