Which lipid mediator is produced by mast cells and basophils by the action of lipoxygenase on arachidonic acid and is responsible for bronchoconstriction and mucus hypersecretion in asthma?

• A Prostaglandin E2 (PGE2)
• B Thromboxane A2 (TXA2)
• C Platelet-activating factor (PAF)
• D Leukotriene C4 (LTC4) ✓

Explanation

Cysteinyl leukotrienes (LTC4, LTD4, LTE4) are produced by mast cells, basophils, and eosinophils via 5-lipoxygenase acting on arachidonic acid. They are potent bronchoconstrictors (1000x more potent than histamine), increase vascular permeability, promote mucus secretion, and recruit eosinophils. They are the molecular basis for leukotriene receptor antagonists (montelukast) in asthma therapy. PGE2 has both bronchoconstrictor and dilator actions. TXA2 primarily causes platelet aggregation and vasoconstriction. PAF causes bronchoconstriction and is derived from membrane phospholipids, not via lipoxygenase.

Reference: Robbins & Cotran Pathologic Basis of Disease, 10th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.