Eritropoitina e doping.

Erythropoietin (EPO) is a glycoprotein growth factor which functions as a classic endocrine hormone. It is produced in the kidney in response to reduced oxygen availability. It then circulates through the body stream to act on erythroid marrow cells, regulating the rate of erythropoiesis. Its production is both inducible and constitutive, with tissue hypoxia providing the signal for gene transcription. EPO directs erythropoiesis through the interaction of the hormone with specific receptors on the surface of erythroid precursor cells. Sports literature reports widespread doping with erythropoietin. Evidence of abuse is manifold but circumstantial and includes, for example, the spate of mysterious deaths of competitive Dutch and Belgian cyclists between 1987 and 1990. Endurance athletes have long sought ways of increasing their hemoglobin levels. These have included physiological methods such as training at high altitudes and illegal and dangerous methods such as blood transfusions and, more recently, EPO abuse. For athletes abusing erythropoietin the rise, in exercising blood pressure, together with the rise in hematocrit and blood viscosity, has obvious and severe implications. Among possible solutions to measure EPO levels in an athlete's biological fluids, the most simple method is a specific serum immunoassay with monoclonal antibody to EPO (ELISA).