erythropoietin
(ĕ-rĭth‵rō-poy'ĕ-tĭn 
)
A cytokine made by the kidneys that stimulates the proliferation of red blood cells. Synthetic erythropoietin (epoetin alfa) is used to treat anemia, esp. in patients with renal or bone marrow failure. Hypertension is a common side effect of the drug.
SEE: blood doping; cytokine; epoetin alfa.
Athletes have used erythropoietin in an attempt to enhance performance. When the hormone is used without medical supervision and in large doses, it can cause an abnormal increase in red blood cell mass and may lead to death.