In CKD, which hormone's reduced production contributes to anemia?

• A. Erythropoietin
• B. Renin
• C. Aldosterone
• D. Calcitriol

Answer: (A)

The key factor driving anemia in CKD is reduced erythropoietin production by the diseased kidneys. Erythropoietin is a hormone made mainly by the kidney’s peritubular interstitial cells in response to low blood oxygen. It travels to the bone marrow and binds to receptors on erythroid progenitor cells, promoting their survival, proliferation, and maturation into red blood cells. When kidney function declines, less erythropoietin is produced, so fewer red blood cells are generated, leading to normocytic, normochromic anemia and symptoms like fatigue and shortness of breath. Other listed hormones, such as renin, aldosterone, and calcitriol, play roles in blood pressure regulation and mineral metabolism, not directly in driving anemia. Management often involves erythropoiesis-stimulating agents and correcting iron availability to support red blood cell production.