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Abstract
The term eicosanoids is a name of compounds which are derived from acid precursor, arachidonic acid . Eicosa means 20 carbon atom , enoic means containing double bond
They are among the most prevalent autacoids(local hormones that do not have specific target organ as the well known” endocrine hormones” and mainly found in every tissue and body fluid
Chemical or mechanical stimulation of the cell membrane induces arachidonic acid release from membrane phospholipids. Once free, it activates several enzyme systems that are variably distributed among different cells. Each cell primarily synthesizes specific eicosanoids
These enzyme systems include Cyclooxygenase (COX) enzyme (with its three isomers COX-1, COX-2 and COX-3), lipoxygenase (LOX) enzyme and epoxygenase enzymes (sytochrome P450 enzymes). these enzyme systems yield different types of eicosanoids including: Prostaglandins(PGs) “ PGD, PGE , PGF2? and PGI2 “ and thromboxanes (TXs) through the syclooxygenase pathway leukotrienes(LTs) “ LTA , LTB , LTC , LTD , LTE” through lipoxygenase pathway. Also, variable biologically active compounds are produced through epoxygenase pathway” still under research” . Via binding to specific G-protein –coupled receptors, eicosanoids exert their cellular effect