erythropoietin (EPO) /erith′rōpō·ē″tin/ [Gk, erythros + poiein, to make] , a glycoprotein hormone synthesized mainly in the kidneys and released into the bloodstream in response to anoxia. The hormone acts to stimulate and to regulate the production of erythrocytes and thus increases the oxygen-carrying capacity of the blood. See also erythropoiesis.
