Why is Erythropoietin (EPO) secreted by the kidneys important for the body?

Erythropoietin (EPO) stimulates the production of Red Blood Cells in the body and it also prevents it from being destroyed.

Explanation:

Erythropoietin is a hormone that is being secreted by specialized cells within the kidney. Its other name is "haematopoietin." Its secretion is dependent on the level of oxygen in the body. For example, when the level of oxygen is low, the kidney secretes more EPO in order to stimulate the production of Red Blood Cells (RBCs), which carry oxygenated blood. On the contrary, when the oxygen level is high, the EPO production is reduced.

A person may experience having too much or too little of EPO. Too much of this could be caused by a tumor. This causes headache, dizziness, pain in the joints, etc. Too little of this could be caused by a kidney disease.