Written by the Fiveable Content Team • Last updated September 2025
Written by the Fiveable Content Team • Last updated September 2025
Definition
Erythropoietin (EPO) is a hormone produced mainly by the kidneys that plays a key role in the production of red blood cells. It signals the bone marrow to increase the production of red blood cells in response to low oxygen levels in tissues.
A condition in which there is insufficient oxygen reaching tissues, often triggering an increase in erythropoietin production.
Bone marrow: A spongy tissue inside bones where hematopoiesis occurs, including the production of red blood cells under the influence of erythropoietin