Hypoxia Triggers Erythropoietin (EPO) Production in the Kidneys

Renal hypoxia → interstitial fibroblasts increase erythropoietin (EPO) synthesis → EPO stimulates bone marrow erythroid progenitors → increased red blood cell production → enhanced oxygen-carrying capacity → corrects hypoxia (negative feedback loop).

This is the physiologic basis for altitude adaptation and recombinant EPO therapy in anemia of CKD/chemotherapy.