n :  any of a group of eicosanoids that are generated in basophils, mast cells, macrophages, and human lung tissue by lipoxygenase-catalyzed oxygenation esp. of arachidonic acid and that participate in allergic responses (as bronchoconstriction in asthma) - see SLOW-REACTING SUBSTANCE OF ANAPHYLAXIS  .
 
 
 
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