Leukotriene

a family of products of eicosanoid metabolism (usually, arachidonic acid) with postulated physiologic activity such as mediation of inflammation and roles in allergic reactions

Description
Leukotrienes differ from the related prostaglandins and thromboxanes by not having a central ring; so named because they were originally discovered in association with leukocytes and of three conjugated double bonds; letters A through F identify the first six metabolites isolated, with subscript numbers to indicate the number of double bonds (e.g., leukotriene C4)