     leukotrienes are a family of eicosanoid inflammatory mediators produced in leukocytes by the oxidation of arachidonic acid by the enzyme arachidonate 5-lipoxygenase. as their name implies, leukotrienes were first discovered in leukocytes, but have since been found in other immune cells. leukotrienes use lipid signaling to convey information to either the cell producing them (autocrine signaling) or neighboring cells (paracrine signaling) in order to regulate immune responses. leukotriene production is usually accompanied by the production of histamine and prostaglandins, which also act as inflammatory mediators. one of their roles (specifically, leukotriene d4) is to trigger contractions in the smooth muscles lining the bronchioles; their overproduction is a major cause of inflammation in asthma and allergic rhinitis.david l. nelson, michael m. cox. lehninger's principles of biochemistry, fifth edition. w.h. freeman and co., 2008, p. 359. leukotriene antagonists are used to treat these disorders by inhibiting the production or activity of leukotrienes. == history and name == the name leukotriene, introduced by swedish biochemist bengt samuelsson in 1979, comes from the words leukocyte and triene (indicating the compound's three conjugated double bonds). what would be later named leukotriene c, "slow reaction smooth muscle-stimulating substance" (srs) was originally described between 1938 and 1940 by feldberg and kellaway.feldberg w, kellaway ch. liberation of histamine and formation of lyscithin-like substances by cobra venom. j physiol 1938;94:187-226. feldberg w, holden hf, kellaway ch. the formation of lyscithin and of a muscle-stimulating substance b
Eicosanoids Immunology