What hormone is secreted by the kidneys in response to low oxygen levels?

The hormone secreted by the kidneys in response to low oxygen levels is erythropoietin. This hormone plays a crucial role in the body's ability to respond to decreases in oxygen availability, often due to conditions such as anemia, high altitudes, or chronic respiratory diseases. When oxygen levels in the blood drop, the kidneys detect this change and increase the production of erythropoietin. Erythropoietin then stimulates the bone marrow to produce more red blood cells, which enhances the oxygen-carrying capacity of the blood, improving overall oxygen delivery to tissues.

Understanding the function of erythropoietin is significant in a clinical context, as it highlights the kidneys' role not only in filtering blood and producing urine but also in regulating vital processes like red blood cell production. This hormone's activity is critical for maintaining proper oxygen levels in the body and is often a focal point for treatments in various anemic conditions.