Leukotriene C4 (LTC4) is the parent cysteinyl leukotriene produced by the LTC4 synthase catalyzed conjugation of glutathione to LTA4. LTC4 is produced by neutrophils, macrophages, mast cells, and by transcellular metabolism in platelets. It is one of the constituents of slow-reacting substance of anaphylaxis (SRS-A) and exhibits potent smooth muscle contracting activity. LTC4-induced bronchoconstriction and enhanced vascular permeability contribute to the pathogenesis of asthma and acute allergic hypersensitivity. The concentration of LTC4 required to produce marked contractions of lung parenchymal strips and isolated tracheal rings is about 1 nM.
