(Science: growth factor, hormone) erythropoietin is a glycoprotein (46 kD) hormone produced by specialised cells in the kidneys that regulates the production of red blood cells in the marrow.
These cells are sensitive to low arterial oxygen concentration and will release erythropoietin when oxygen is low. Erythropoietin stimulates the bone marrow to produce more red blood cells (to increase the oxygen caring capacity of the blood).
The measurement of this hormone in the bloodstream can indicate bone marrow disorders or kidney Disease. Normal levels of erythropoietin are 0 to 19 mU/ml (milliunits per millilitre).
Elevated levels can be seen in polycythaemia rubra vera. Lower than normal values are seen in chronic renal failure.Recombinant erythopoeitin is now being used therapeutically in patients.