What is the role of EPO?

• A. Regulates blood sugar levels.
• B. Stimulates the production of red blood cells.
• C. Promotes platelet aggregation.
• D. Inhibits angiogenesis.

Answer: (B)

Erythropoietin is a hormone that stimulates the production of red blood cells in the bone marrow in response to low oxygen levels. When tissues become hypoxic, the kidneys release EPO, which travels to the marrow and binds to receptors on erythroid progenitor cells. This binding promotes their proliferation and maturation into mature red blood cells, increasing the blood’s capacity to carry oxygen. This regulatory loop helps adapt to reduced oxygen availability.

That’s why the best choice states that EPO stimulates red blood cell production. The other options involve processes not driven by EPO: regulating blood sugar is handled by insulin and glucagon, promoting platelet aggregation involves platelet activation pathways, and inhibiting angiogenesis is not a primary role of EPO (its main action is erythropoiesis).