Arachidonic acid released from membrane phospholipids by phospholipase A2 can be metabolized via the COX pathway or the lipoxygenase pathway. Leukotriene B4 (LTB4), produced by the lipoxygenase pathway, mediates which primary inflammatory action?

• A Fever induction by acting on the hypothalamic thermoregulatory center
• B Vasodilation and increased vascular permeability
• C Platelet aggregation and vasoconstriction
• D Potent chemotaxis and activation of neutrophils ✓

Explanation

LTB4 is produced by neutrophils and macrophages via 5-lipoxygenase and is a potent chemotactic agent for neutrophils, eosinophils, and monocytes. Cysteinyl leukotrienes (LTC4, LTD4, LTE4) cause bronchoconstriction, vasodilation, and increased permeability. PGE2 causes fever. TXA2 causes platelet aggregation and vasoconstriction.

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

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

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