What physiological role does erythropoietin primarily serve in the body?

Erythropoietin is a glycoprotein hormone primarily produced by the kidneys in response to low oxygen levels in the blood. Its main physiological role is to stimulate the production of red blood cells (erythrocytes) in the bone marrow. When oxygen levels are low, erythropoietin is released into the bloodstream, where it binds to specific receptors on progenitor cells in the bone marrow, promoting their differentiation into red blood cells.

These red blood cells are crucial for transporting oxygen throughout the body. By increasing red blood cell production, erythropoietin effectively enhances the oxygen-carrying capacity of the blood, which is vital in maintaining cellular metabolism and overall physiological function. This process is especially important in conditions such as anemia, hypoxia, or after significant blood loss, where erythropoietin helps to restore adequate oxygen levels in the tissues.