Eicosanoid

eicosanoidsarachidonic acid derivativesEicosanoid Metabolism
Eicosanoids are signaling molecules made by the enzymatic or non-enzymatic oxidation of arachidonic acid or other polyunsaturated fatty acids (PUFAs) that are, similar to arachidonic acid, 20 carbon units in length.wikipedia
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20-Hydroxyeicosatetraenoic acid

20-hydroxyarachidonic acid
A subset of cytochrome P450 (CYP450) microsome-bound ω-hydroxylases (see 20-Hydroxyeicosatetraenoic acid) metabolize arachidonic acid to 20-Hydroxyeicosatetraenoic acid (20-HETE) and 19-hydroxyeicosatetraenoic acid by an omega oxidation reaction.
20-Hydroxyeicosatetraenoic acid, also known as 20-HETE or 20-hydroxy-5Z,8Z,11Z,14Z-eicosatetraenoic acid, is an eicosanoid metabolite of arachidonic acid that has a wide range of effects on the vascular system including the regulation of vascular tone, blood flow to specific organs, sodium and fluid transport in the kidney, and vascular pathway remodeling.

Endocrine system

endocrineendocrinologicalendocrine organ
Eicosanoids may also act as endocrine agents to control the function of distant cells.
Hormones can consist of either amino acid complexes, steroids, eicosanoids, leukotrienes, or prostaglandins.

Eoxin

Eoxins
There are multiple subfamilies of eicosanoids, including most prominently the prostaglandins, thromboxanes, leukotrienes, lipoxins, resolvins, and eoxins.
Eoxins are proposed to be a family of proinflammatory eicosanoids (signaling compounds that regulate inflammatory and immune responses).

Inflammation

inflammatoryinflammatory responseinflamed
Eicosanoids function in diverse physiological systems and pathological processes such as: mounting or inhibiting inflammation, allergy, fever and other immune responses; regulating the abortion of pregnancy and normal childbirth; contributing to the perception of pain; regulating cell growth; controlling blood pressure; and modulating the regional flow of blood to tissues.
Upon contact with PAMPs, tissue macrophages and mastocytes release vasoactive amines such as histamine and serotonin, as well as eicosanoids such as prostaglandin E2 and leukotriene B4 to remodel the local vasculature.

Arachidonic acid

arachidonic acid metabolismarachidonatearachidonic
Eicosanoids are signaling molecules made by the enzymatic or non-enzymatic oxidation of arachidonic acid or other polyunsaturated fatty acids (PUFAs) that are, similar to arachidonic acid, 20 carbon units in length. The enzyme 5-lipoxygenase (5-LO or ALOX5) converts arachidonic acid into 5-hydroperoxyeicosatetraenoic acid (5-HPETE), which may be released and rapidly reduced to 5-hydroxyeicosatetraenoic acid (5-HETE) by ubiquitous cellular glutathione-dependent peroxidases.

Prostacyclin

epoprostenolPGI2Flolan
Prostacyclin (also called prostaglandin I2 or PGI 2 ) is a prostaglandin member of the eicosanoid family of lipid molecules.

Cyclopentenone prostaglandins

Cyclopentenone prostaglandin
It is metabolized by (see diagram in Prostanoids: a) the Prostaglandin E synthase pathway in which any one of three isozymes, PTGES, PTGES2, or PTGES3, convert PGH2 to PGE2 (subsequent products of this pathway include PGA2 and PGB2 (see Prostanoid#Biosynthesis); b) PGF synthase which converts PGH2 to PGF2α; c) Prostaglandin D2 synthase which converts PGH2 to PGD2 (subsequent products in this pathway include 15-dPGJ2 (see Cyclopentenone prostaglandin); d) thromboxane synthase which converts PGH2 to TXA2 (subsequent products in this pathway include TXB2); and e) Prostacyclin synthase which converts PGH2 to PGI2 (subsequent products in this pathway include 6-keto-PGFα.
Cyclopentenone prostaglandins are a subset of prostaglandins (PGs) or prostanoids (see eicosanoid#classic eicosanoids and eicosanoid#nonclassic eicosanoids) that has 15-deoxy-Δ12,14-prostaglandin J2 (15-d-Δ12,14-PGJ2), Δ12-PGJ2, and PGJ2 as its most prominent members but also including PGA2, PGA1, and, while not classified as such, other PGs.

Eicosapentaenoic acid

EPA20:5n-3eicosapentaenoate
The same CYPs but also CYP4A1, CYP4F8, and CYP4F12 metabolize eicosapentaenoic acid to five epoxide epoxyeicosatetraenoic acids (EEQs) viz., 17,18-EEQ, 14,15-EEQ, 11,12-EEQ.
EPA is a polyunsaturated fatty acid (PUFA) that acts as a precursor for prostaglandin-3 (which inhibits platelet aggregation), thromboxane-3, and leukotriene-5 eicosanoids.

Nonclassic eicosanoid

nonclassical eicosanoid
Nonclassic eicosanoids are biologically active signaling molecules made by oxygenation of twenty-carbon fatty acids other than the classic eicosanoids.

Cannabinoid

cannabinoidsendocannabinoidendocannabinoids
Synthetic cannabinoids encompass a variety of distinct chemical classes: the classical cannabinoids structurally related to THC, the nonclassical cannabinoids (cannabimimetics) including the aminoalkylindoles, 1,5-diarylpyrazoles, quinolines, and arylsulfonamides as well as eicosanoids related to endocannabinoids.

Oxylipin

oxylipinsoxidized lipid
Eicosanoids are a sub-category of oxylipins, i.e. oxidized fatty acids of diverse carbon units in length, and are distinguished from other oxylipins by their overwhelming importance as cell signaling molecules.
Oxylipins in animals, referred to as eicosanoids (Greek icosa; twenty) because of their formation from twenty-carbon essential fatty acids, have potent and often opposing effects on e.g. smooth muscle (vasculature, myometrium) and blood platelets.

Virodhamine

O-arachidonoyl-ethanolamine
Virodhamine (O-arachidonoyl ethanolamine; O-AEA) is an endocannabinoid and a nonclassic eicosanoid, derived from arachidonic acid.

Phospholipase A2

phospholipase A 2 PLA2cPLA2
The activated cells then mobilize enzymes, termed phospholipase A 2 's (PLA 2 s), capable of releasing ω-6 and ω-3 fatty acids from membrane storage.
Upon downstream modification by cyclooxygenases or lipoxygenases, arachidonic acid is modified into active compounds called eicosanoids.

Essential fatty acid interactions

arachidonic acidarachidonic acid cascadeEssential fatty acid interactions: The paradox of dietary GLA
These two parallel cascades soften the inflammatory promoting effects of certain eicosanoids made from AA.

Prostaglandin

prostaglandinsprostoglandinprostaglandins a
There are multiple subfamilies of eicosanoids, including most prominently the prostaglandins, thromboxanes, leukotrienes, lipoxins, resolvins, and eoxins.
The prostaglandins (PG) are a group of physiologically active lipid compounds called eicosanoids having diverse hormone-like effects in animals.

5-Hydroxyeicosatetraenoic acid

5-HETE5-Hydroxyicosatetraenoic acid5-Hydroxyicosatetraenoic acid and 5-oxo-eicosatetraenoic acid
The enzyme 5-lipoxygenase (5-LO or ALOX5) converts arachidonic acid into 5-hydroperoxyeicosatetraenoic acid (5-HPETE), which may be released and rapidly reduced to 5-hydroxyeicosatetraenoic acid (5-HETE) by ubiquitous cellular glutathione-dependent peroxidases.
5-Hydroxyeicosatetraenoic acid (5-HETE, 5(S)-HETE, or 5S-HETE) is an eicosanoid, i.e. a metabolite of arachidonic acid.

Leukotriene

leukotrienesleukotriene a4anti-leukotrienes
There are multiple subfamilies of eicosanoids, including most prominently the prostaglandins, thromboxanes, leukotrienes, lipoxins, resolvins, and eoxins.
Leukotrienes are a family of eicosanoid inflammatory mediators produced in leukocytes by the oxidation of arachidonic acid (AA) and the essential fatty acid eicosapentaenoic acid (EPA) by the enzyme arachidonate 5-lipoxygenase.

Lipid

lipidsglycerolipidfat
Examples of biologically important fatty acids include the eicosanoids, derived primarily from arachidonic acid and eicosapentaenoic acid, that include prostaglandins, leukotrienes, and thromboxanes.

Thromboxane

thromboxanesreceptors, thromboxanethromboxane A 2
There are multiple subfamilies of eicosanoids, including most prominently the prostaglandins, thromboxanes, leukotrienes, lipoxins, resolvins, and eoxins.
Thromboxane is a member of the family of lipids known as eicosanoids.

Epoxygenase

cytochrome P450 epoxygenase
This polyunsaturated fatty acid is metabolized by cyclooxygenases to various prostaglandin, thromboxane, and prostacyclin metabolites in what has been termed the first pathway of eicosanoid production; it is also metabolized by various lipoxygenases to hydroxyeicosatetraenoic acids (e.g. 5-Hydroxyeicosatetraenoic acid, 12-Hydroxyeicosatetraenoic acid, 15-hydroxyicosatetraenoic acid) and leukotrienes (e.g. leukotriene B4, leukotriene C4) in what has been termed the second pathway of eicosanoid production.

Prostanoid

prostanoids
It is metabolized by (see diagram in Prostanoids: a) the Prostaglandin E synthase pathway in which any one of three isozymes, PTGES, PTGES2, or PTGES3, convert PGH2 to PGE2 (subsequent products of this pathway include PGA2 and PGB2 (see Prostanoid#Biosynthesis); b) PGF synthase which converts PGH2 to PGF2α; c) Prostaglandin D2 synthase which converts PGH2 to PGD2 (subsequent products in this pathway include 15-dPGJ2 (see Cyclopentenone prostaglandin); d) thromboxane synthase which converts PGH2 to TXA2 (subsequent products in this pathway include TXB2); and e) Prostacyclin synthase which converts PGH2 to PGI2 (subsequent products in this pathway include 6-keto-PGFα.
Prostanoids are a subclass of eicosanoids consisting of the prostaglandins (mediators of inflammatory and anaphylactic reactions), the thromboxanes (mediators of vasoconstriction), and the prostacyclins (active in the resolution phase of inflammation.)

Hepoxilin

Hepoxilins
The enzyme arachidonate 12-lipoxygenase (12-LO or ALOX12) metabolizes arachidonic acid to the S stereoisomer of 12-hydroperoxyeicosatetraenoic acid (5-HPETE) which is rapidly reduced by cellular peroxidases to the S stereoisomer of 12-hydroxyeicosatetraenoic acid (12-HETE) or further metabolized to hepoxilins (Hx) such as HxA3 and HxB.
HxA3, HxB3, and their isomers are distinguished from most other eicosanoids (i.e. signaling molecules made by oxidation of 20-carbon fatty acids) in that they contain both epoxide and hydroxyl residues; they are structurally differentiated in particular from two other classes of arachidonic acid-derived eicosanoids, the leukotrienes and lipoxins, in that they lack conjugated double bonds.

15-Hydroxyeicosatetraenoic acid

15-Hydroxyicosatetraenoic acid15(''S'')-hydroperoxyeicosapentaenoic acid15(S)-hydroperoxyeicosatetraenoic acid
The enzymes 15-lipoxygenase-1 (15-LO-1 or ALOX15) and 15-lipoxygenase-2 (15-LO-2, ALOX15B) metabolize arachidonic acid to the S stereoisomer of 15-Hydroperoxyeicosatetraenoic acid (15(S)-HPETE) which is rapidly reduced by cellular peroxidases to the S stereoisomer of 15-Hydroxyicosatetraenoic acid (15(S)-HETE).
15-Hydroxyeicosatetraenoic acid (also termed 15-HETE, 15(S)-HETE, and 15S-HETE) is an eicosanoid, i.e. a metabolite of arachidonic acid.

Lipoxygenase

lipoxygenaseslipoxidase5-lipoxygenase
The eicosanoid pathways (via lipoxygenase or COX) add molecular oxygen (O 2 ).
In mammals a number of lipoxygenases isozymes are involved in the metabolism of eicosanoids (such as prostaglandins, leukotrienes and nonclassic eicosanoids).