Erythropoietin acts by binding to the specific erythropoietin receptor (EpoR).
Erythropoietin production is stimulated by the reduction of oxygen in the renal arteries. Erythropoietin produced in the kidney/bone marrow system stimulates stem cells in the bone marrow to increase production of erythrocytes (red blood cells). The role of paracrine erythropoietin in the brain and uterus is not fully elucidated.
Another substance in the same class is darbepoetin.