Erythropoietin (EPO) is a glycoprotein hormone produced by the kidney in response to oxygen deficiency. It stimulates the formation red blood cells in the bone marrow, thus increasing oxygen carrying capacity of the blood. In medical practice it is used for treatment of certain types of anemia, however it also found its place in sports.
Muscles are generators which consume glucose and oxygen and convert them into energy. Since endurance of the muscles directly depends on oxygen consumption, EPO became performance-enhancing drug among athletes of aerobic sports (boxers, runners, cyclists, football players etc).
Before EPO athletes practiced “blood doping” which means removal, storing and then transfusion of the blood before competition. As a result it boosts the amount of erythrocytes and accordingly increases endurance. However, this procedure is messy and risky, therefore EPO is more preferable option for this purpose.
Doping tests
Initially it was difficult to detect EPO, therefore athletes were banned according to elevated hematocrit level. Nowadays EPO tests are more precise. As a rule, erythropoietin is detected in urine or blood samples. In the blood it is detected with greater probability than in the urine.
Its half-life is 5-9 hours, that is, the probability of detection is significantly reduced after 2-3 days. Therefore athletes should stop using the drug few days before the contest. It’s better to use smaller doses on regular basis than do one big injection. Firstly it is more natural, secondly it reduces detectability.
Before the test you should fast for 8-10 h (overnight) and sometimes to lie quietly for half an hour. Heparin or introduction of proteases into the bladder (via catheter) is usually used as masking agent for EPO blood/urine tests.
Side effects
Since EPO increases the amount of red blood cells, its major side effect is increased blood viscosity, which may lead to blood clot formation and vein thrombosis. Therefore avoid dehydration, drink a lot of liquids and take aspirin (or anticoagulants in case of high doses).