In biochemistry, eicosanoids are a class of oxygenated hydrophobic cytokines that largely function as a autocrine and paracrine mediators. All eicosanoids derive from arachidonic acid, a polyunsaturated fatty acid. ==Nomenclature== Eicosa (Greek language: twenty, see eicosahedron) denotes the amount of carbon atoms in arachidonic acid. The numbering of eicosanoids is used to denote the number of double bonds. The prostanoids generally have two, while the leukotrienes have four. ==Synthesis== The first step of eicosanoid biosynthesis is the release of arachidonic acid from phospholipids (by phospholipase A2) or diacylglycerol (by phospholipase C). Arachidonic acid has two possible fates: * Lipoxygenases pathway: ** Leukotrienes * Cyclooxygenase pathway ("prostanoids"): ** Prostaglandins ** Prostacyclin ** Thromboxanes === Leukotrienes === 5-lipoxygenase uses the nuclear-membrane protein cofactor (biochemistry) 5-lipoxygenase-activating protein (FLAP) to sequentially convert arachidonic acid, first into 5-hydroperoxyeicosatetraenoic acid (5-HPETE), and then 5-HPETE into leukotriene A4 (LTA4). LTA4 may be converted into LTB4 by the enzyme leukotriene A4 epoxide hydrolase. Eosinophils, mast cells, and alveoli macrophages use the enzyme leukotriene C4 synthase to conjugate glutathione with LTA4 to make leukotriene C4 (LTC4). LTC4 is transported out of the cell, where a glutamic acid moiety is removed from it to make leukotriene D4 (LTD4). LTD4 is cleaved by dipeptidases to make leukotriene E4 (LTE4). LTC4, LTD4 and LTE4 all contain cysteine and are collectively known as the cysteinyl leukotrienes. ===Prostanoids=== All prostanoids originate from prostaglandin H2 (PGH2), which is converted by different enzymes into the various compounds. The enzyme PGH2-synthase is in fact a combination of a peroxidase and a cyclooxygenase (''Cox-1'' or ''Cox-2''). The ''Cox'' enzymes are the molecular target of the NSAIDs, such as aspirin (see below). PGH2 is converted: * By PGE synthetase into PGE (which in turn is converted into PGF) * By PGD synthetase into PGD * By Prostacyclin synthase into prostacyclin (PGI2) * By Thromboxane synthase into thromboxanes ==Receptors== There are specific receptors for all eicosanoids (see also specific articles): * Leukotrienes: ** CysLT1 (Cysteinyl leukotriene receptor type 1) ** CysLT2 (Cysteinyl leukotriene receptor type 2) ** BLT1 (Leukotriene B4 receptor) * Prostanoids: ** PGD2: DP-(PGD2) ** PGE2: *** EP1-(PGE2) *** EP2-(PGE2) *** EP3-(PGE2) *** EP4-(PGE2) ** PGF2α: FP-(PGF2α) ** PGI2 (prostacyclin): IP-(PGI2) ** TXA2 (thromboxane): TP-(TXA2) ==Function and pharmacology== ===Leukotrienes=== Leukotrienes play an important role in inflammation, and blocking leukotriene receptors can play a role in the management of asthma (montelukast, zafirlukast). ===Prostanoids=== ''See also the main article prostaglandin'' Prostanoids mediate local symptoms of inflammation: vasoconstriction or vasodilation, coagulation, pain and fever. Inhibition of cyclooxygenase, specifically the inducible COX II isoform, is the hallmark of NSAIDs (non-steroidal anti-inflammatory drugs), such as aspirin. COX II is responsible for pain and inflammation, while COX I is responsible for platelet clotting actions. Lipids Eicosanoids
This page looks good. I've never studied this topic, so there's not much that I can say about it. It might be nice to add some diagrams of molecular structures. I know that Canvas is a good program for this, but I won't be able to draw them any time soon. Do you know anything about the receptors for these hormones? I'm going on a Wiki-vacation, so I won't be available for more input for a while. Keep up the good work! User:AdamRetchless 08:15, 4 May 2004 (UTC) :My source has quite a bit on the receptors, but they are quite specific for leukotrienes, prostacyclin etc. I thought it would be better to include this in the related articles, rather than on eicosanoid proper. User:Jfdwolff
User:Jfdwolff | User_talk:Jfdwolff 09:28, 4 May 2004 (UTC)
See other meanings of words starting from letter:
Words begining with Eicosanoid:
Eicosanoid
Eicosanoid
Eicosanoids
Eicosanoids
Eicosanoids
Eicosanoid
In biochemistry, eicosanoids are a class of oxygenated hydrophobic cytokines that largely function as a autocrine and paracrine mediators. All eicosanoids derive from arachidonic acid, a polyunsaturated fatty acid. ==Nomenclature== Eicosa (Greek language: twenty, see eicosahedron) denotes the amount of carbon atoms in arachidonic acid. The numbering of eicosanoids is used to denote the number of double bonds. The prostanoids generally have two, while the leukotrienes have four. ==Synthesis== The first step of eicosanoid biosynthesis is the release of arachidonic acid from phospholipids (by phospholipase A2) or diacylglycerol (by phospholipase C). Arachidonic acid has two possible fates: * Lipoxygenases pathway: ** Leukotrienes * Cyclooxygenase pathway ("prostanoids"): ** Prostaglandins ** Prostacyclin ** Thromboxanes === Leukotrienes === 5-lipoxygenase uses the nuclear-membrane protein cofactor (biochemistry) 5-lipoxygenase-activating protein (FLAP) to sequentially convert arachidonic acid, first into 5-hydroperoxyeicosatetraenoic acid (5-HPETE), and then 5-HPETE into leukotriene A4 (LTA4). LTA4 may be converted into LTB4 by the enzyme leukotriene A4 epoxide hydrolase. Eosinophils, mast cells, and alveoli macrophages use the enzyme leukotriene C4 synthase to conjugate glutathione with LTA4 to make leukotriene C4 (LTC4). LTC4 is transported out of the cell, where a glutamic acid moiety is removed from it to make leukotriene D4 (LTD4). LTD4 is cleaved by dipeptidases to make leukotriene E4 (LTE4). LTC4, LTD4 and LTE4 all contain cysteine and are collectively known as the cysteinyl leukotrienes. ===Prostanoids=== All prostanoids originate from prostaglandin H2 (PGH2), which is converted by different enzymes into the various compounds. The enzyme PGH2-synthase is in fact a combination of a peroxidase and a cyclooxygenase (''Cox-1'' or ''Cox-2''). The ''Cox'' enzymes are the molecular target of the NSAIDs, such as aspirin (see below). PGH2 is converted: * By PGE synthetase into PGE (which in turn is converted into PGF) * By PGD synthetase into PGD * By Prostacyclin synthase into prostacyclin (PGI2) * By Thromboxane synthase into thromboxanes ==Receptors== There are specific receptors for all eicosanoids (see also specific articles): * Leukotrienes: ** CysLT1 (Cysteinyl leukotriene receptor type 1) ** CysLT2 (Cysteinyl leukotriene receptor type 2) ** BLT1 (Leukotriene B4 receptor) * Prostanoids: ** PGD2: DP-(PGD2) ** PGE2: *** EP1-(PGE2) *** EP2-(PGE2) *** EP3-(PGE2) *** EP4-(PGE2) ** PGF2α: FP-(PGF2α) ** PGI2 (prostacyclin): IP-(PGI2) ** TXA2 (thromboxane): TP-(TXA2) ==Function and pharmacology== ===Leukotrienes=== Leukotrienes play an important role in inflammation, and blocking leukotriene receptors can play a role in the management of asthma (montelukast, zafirlukast). ===Prostanoids=== ''See also the main article prostaglandin'' Prostanoids mediate local symptoms of inflammation: vasoconstriction or vasodilation, coagulation, pain and fever. Inhibition of cyclooxygenase, specifically the inducible COX II isoform, is the hallmark of NSAIDs (non-steroidal anti-inflammatory drugs), such as aspirin. COX II is responsible for pain and inflammation, while COX I is responsible for platelet clotting actions. Lipids Eicosanoids
Eicosanoid
This page looks good. I've never studied this topic, so there's not much that I can say about it. It might be nice to add some diagrams of molecular structures. I know that Canvas is a good program for this, but I won't be able to draw them any time soon. Do you know anything about the receptors for these hormones? I'm going on a Wiki-vacation, so I won't be available for more input for a while. Keep up the good work! User:AdamRetchless 08:15, 4 May 2004 (UTC) :My source has quite a bit on the receptors, but they are quite specific for leukotrienes, prostacyclin etc. I thought it would be better to include this in the related articles, rather than on eicosanoid proper. User:Jfdwolff
User:Jfdwolff | User_talk:Jfdwolff 09:28, 4 May 2004 (UTC)
See other meanings of words starting from letter:
E
EA | EB | EC | ED | EF | EG | EH | EI | EJ | EK | EL | EM | EN | EO | EP | ER | ES | ET | EU | EW | EX | EY | EZ |Words begining with Eicosanoid:
Eicosanoid
Eicosanoid
Eicosanoids
Eicosanoids
Eicosanoids
These materials are based on Wikipedia and licensed under the GNU FDL
Untitled Document
| Linki sponsorowane | Tani hosting | Pozycjonowanie |
YouTube.com videos better site than Turbo Tax 2007
