COX-1 makes prostaglandins do what?

• A. Increase inflammation and cause pain
• B. Decrease fever
• C. Protect stomach lining and cause platelet aggregation
• D. Promote gastric acid secretion

Answer: (C)

COX-1 is constitutively active and produces prostaglandins that support normal bodily functions, including protecting the stomach and helping with blood clotting. The prostaglandins made by COX-1 in the gastric mucosa help maintain the protective lining by stimulating mucus and bicarbonate production and maintaining mucosal blood flow. In platelets, COX-1 drives production of thromboxane A2, which promotes platelet aggregation and clot formation. That combination—gastric protection and hemostasis—is what COX-1–derived prostaglandins do.

This contrasts with the other effects associated with COX-2, which is more involved in promoting inflammation and fever, and with the idea of increasing gastric acid secretion, which COX-1–mediated prostaglandins do not promote (they tend to protect against acid injury).