Glucocorticoids exert part of their anti-inflammatory effect by inducing the synthesis of lipocortin-1 (annexin A1), which inhibits a key enzyme in eicosanoid biosynthesis. Which enzyme is inhibited?

• A Cyclooxygenase-1 (COX-1)
• B 5-Lipoxygenase (5-LOX)
• C Thromboxane synthase
• D Phospholipase A2 (cPLA2) ✓

Explanation

Lipocortin-1 inhibits cytosolic phospholipase A2 (cPLA2), preventing release of arachidonic acid from membrane phospholipids. This is the rate-limiting step in all eicosanoid synthesis. Aspirin and NSAIDs act downstream at COX. Zileuton inhibits 5-LOX directly, not via lipocortin.

Reference: Goodman and Gilman's The Pharmacological Basis of Therapeutics, 14th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

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