Leukotriene
A class of inflammatory lipid mediators derived from arachidonic acid that promote bronchoconstriction, vascular permeability, and immune cell recruitment. Leukotrienes contribute to allergic inflammation and asthma and are part of the broader inflammatory milieu modulated by immune-active peptide drugs.
Technical Context
Leukotrienes are synthesised from arachidonic acid by 5-lipoxygenase (5-LOX) → LTA4 → LTB4 (potent neutrophil chemoattractant via BLT1 receptor) or cysteinyl leukotrienes (LTC4, LTD4, LTE4 — formerly 'slow-reacting substance of anaphylaxis' — potent bronchoconstrictors, increase vascular permeability, stimulate mucus secretion; act through CysLT1 and CysLT2 receptors). Leukotrienes contribute to: asthma (bronchoconstriction, mucus hypersecretion, airway inflammation), allergic rhinitis, and anaphylaxis. Leukotriene receptor antagonists (montelukast) are established asthma therapies. Corticotropin-stimulated cortisol inhibits both COX (prostaglandin) and 5-LOX (leukotriene) pathways via lipocortin-1-mediated phospholipase A2 inhibition, providing broader anti-inflammatory coverage than NSAIDs (which only block COX). This dual pathway inhibition contributes to corticotropin's efficacy in inflammatory conditions.