other نقش لکوترین ها در دستگاه تنفس و بیماری آسم بین رشته ای ( مدیریت آموزشی، تحقیقات آموزشی، آموزش پزشکی ) Interdisciplinary (Educational Management, Educational research, Statistics, Medical education مروری Review <span style="font-family:tahoma;">این مقاله چکیده فارسی ندارد.</span> Polyunsaturated fatty acids play a role as precursors of biolo&shy;gically active compounds that can act as mediators or modulators&nbsp; of various cell functions. Thus three main groups of derivatives&shy; the prostaglandins, the thromboxanes, and recently discovered&nbsp; leukotrienes are formed by oxygenation and further transformation&nbsp;of various polyunsaturated fatty acids of which arachidonic acid&nbsp; plays the most significant role. In man the predominant prostag&shy;<br> landin precursor is arachidonic acid,released from membrane&nbsp; phospholipids by one or more lipases. Arachidonic acid then be&shy; comes substrate for two enzymes: cyclooxygenase, Which transforms&nbsp;arachidonic acid into prostaglandins and thromboxanes, and lipoxy_&nbsp;genase which is involved in the formation of the leukotrienes.&nbsp; The enzyme cyclooxygenase in ubiquitous in mammalian tissues and&nbsp; is a microsomal enzyme that in the presence of oxygen, attacks the&nbsp; arachidonic acid, whereas 5-or 12-lipoxygenases have been indenti&shy;fied only in platelets, lungs, white cells and epicardium. The soluble enzyme lipoxygenase introduces a hydroperoxide group into arachidonic acid, resulting in the formation of hydroperoxyeicosatetraenoate&nbsp; (HPETE). This product can either be dicomposed to the hydroxyeicos&shy; atetraenoic acid(HETE) or to the unstable intermediate oxidoeicosa&shy;tetraenoate, called leukotriene A4(LTA4). Hydrolysis of LTA4 leads&nbsp; to the formation of leukotriene B4(LTB4). Alternatively, LTA4 can&nbsp;be conjugated with glutathione to yieled the formation of leuko&shy;triene C4(LTC4). Successive decomposition of the amino acids leads&nbsp;to the metabolic products leukotriene D4(LTD4) and leukotriene&nbsp;E4(LTE4). Further steps in the metabolism of leukotrienes are as&nbsp;yet unknown.&nbsp;The prefix leuko in leukotrienes results from the fact that these&nbsp;compounds were originally isolated from leukocytes, and suffix&nbsp;triene indicates that the compounds all contain a triene structure.&nbsp;The capital letters A-E repre$ent the chronological division of&nbsp; the discovered structures. Slow reacting substance of anaphylaxis&nbsp; (SRS-A) is released by various stimuli, including immunological&nbsp; challenge, and has long been considered as mediator of immediate&nbsp;hypersensitivity reactions,such as bronchoconstriction in&nbsp; allergic asthma. The chemical composition of this mediator was&nbsp;recently determined and shwon to be a mixture of 5-lipoxygenase&nbsp; derived products, namely leukotrienes. Leukotriene C4(LTC4) and&nbsp; its two immediate metabolites, leukotriene D4 and E4 have been&nbsp; identified the major active constituents of SRS-A. These three&nbsp;leukotrienes are outstanding bronchoconstrictors and potent&nbsp; inducers of tissue edema-Perturbations that indeed play a major&nbsp;role in the pathophysiology of bronchial asthma.&nbsp;The purpose of this review is to present information which can help. لکوترین, دستگاه تنفس, آسم Leukotrienes, Respiratory, Tract, Asthma 48 57 http://pejouhesh.sbmu.ac.ir/browse.php?a_code=A-10-3973-321&slc_lang=other&sid=1 Mohammad Nouri محمد نوری 100319475328460019512 100319475328460019512 Yes Jundi Shabour University, Ahvaz, Iran. دانشگاه جندی شابور، اهواز، ایران.