Fatty acids arachidonic

The key substrate for synthesis of the eicosanoids is the omega-6,20-carbon fatty acid arachidonic acid ... 

MUFA- monounsaturated fatty acid PUFA - polyunsaturated fatty acid. Arachidonic acid itself can function as a messenger (see below). 

A summary of the processes for producing the eicosanoids from the polyunsaturated fatty acid, arachidonic acid, is presented in Figure 11.27. The two enzymes separate for synthesising the prostanoids or the leucotrienes are cyclooxygenase and lipoxygenase, respectively. Whether prostanoids or leucotrienes are produced in any given tissue will depend on the relative activities of these two enzymes in that tissue. 

The major omega-3 fatty acid in hsh oil is eicosapentae-noic acid, which contains hve double bonds compared with only four present in the omega-6 fatty acid, arachidonic acid. When eicosapentaenoic acid is substrate for eico-sanoid production, it gives rise to prostacyclins and thromboxanes of the three series (Figure 22.9(a)) whereas when arachidonic acid is substrate, it gives rise to the two series, thromboxane A2 and prostacyclin I2. Thromboxane A3 has... 

Another commercially available product containing naturally occurring marine products is Formulaid , produced by Martek Biosciences as a nutritional supplement for infant formulas. Formulaid contains two fatty acids, arachidonic acid (ARA) and docosahexaenoic acid (DHA), extracted from a variety of marine microalgae. ARA and DHA are the most abundant polyunsaturated fatty acids found in breast milk, and they are the most important fatty acids used in the development of brain gray matter. They are especially desirable for use in infant formulas because they come from nonmeat sources and can be advertised as vegetarian additives to the product. 

Essential fatty acids are fatty acids that have to be supplied in the diet. Without exception, these are all polyunsaturated fatty acids the C20 fatty acid arachidonic add (20 4 5,8,11,14) and the two Cis acids linoleic add (18 2 9,12) and linolenic add (18 3 9,12,15). The animal organism requires arachidonic acid to synthesize eicosanoids... 

The eicosanoids are a group of signaling substances that arise from the C-20 fatty acid arachidonic add and therefore usually contain 20 C atoms (Greek eicosa = 20). As mediators, they influence a large number of physiological processes (see below). Eicosanoid metabolism is therefore an important drug target. As short-lived substances, eicosanoids only act in the vicinity of their site of synthesis (paracrine effect see p.372). 

Biosynthesis. Almost all of the body s cells form eicosanoids. Membrane phospholipids that contain the polyunsaturated fatty acid arachidonic acid (20 4 see p.48) provide the starting material. 

Figure 1.9. Overview of the biosynthesis of ecosanoids. The 20 carbon fatty acid arachidonic acid is released from cell membrane phospholipids by the actions of phospholipase A2. Free arachidonic acid forms the precursor of prostaglandins and thromboxanes via the multi-enz5une cyclooxygenase pathway, while leukotrienes are formed via the lipoxygenase pathway...

The eicosanoids, so called because of their derivation from a 20-carbon unsaturated fatty acid, arachidonic acid (eicosatetraenoic acid), are obtained from membrane phospholipids and synthesized de novo at the time of cellular stimulation. Arachidonic acid is cleaved from membrane-bound phosphatidylcholine by the enzyme phospholipase A2. Alternatively, arachidonic acid may be derived by the sequential actions of phospholipase C and diacylglyceryl lipase. Arachidonic acid can then follow either of two enzymatic pathways that result in the production of inflammatory mediators. The pathway initiated by cyclooxygenase (COX) produces prostaglandins the lipoxygenase pathway generates leukotrienes (Fig. 36.2). 

Prostaglandins, thromboxane, and the leukotrienes are lipids that are collectively called eicosanoids, since they are all derived from the C20 fatty acid, arachidonic acid [eicosa (Gr.) = twenty]. Over the past twenty years, the eicosanoids have emerged as important molecules around which to target drug design and development. 

Eicosanoids The eicosanoid hormones (prostaglandins, thromboxanes, and leukotrienes) are derived from the 20-carbon polyunsaturated fatty acid arachidonate. 

AB Rifkind Cornell University Medical Center, Ithaca, NY Use a chick embryo model to investigate whether 2,3,7,8-TCDD-induced P-450 participates in 2,3,7,8-TCDD toxicity by metabolizing endogenous compounds, such as the membrane fatty acid, arachidonic acid (AA), to biologically active metabolites that can affect cell signals and thereby modulate toxicity ... 

The first part of PI consists of two fatty acids esterified to a glycerol. One of the fatty acids is the unsaturated fatty acid arachidonic acid (20 4), bound to carbon 2 of the glycerol. The other fatty acid is usually stearate (18 0). The combination of two fatty acids esterified to glycerol is called diacylglycerol, abbreviated DAG. 

Prostaglandins Endogenous chemical mediators involved in inflammation derived from the cellular membrane unsaturated fatty acid arachidonic acid. 

CYP4 5 12 Fatty acids, arachidonic acid, eicosanoids... 

Highly Unsaturated Fatty Acids Arachidonic acid (AA) C20 4 0)6 C20 4A 5.8.11.14 cA-jCW-jCA-jCW-S,8,11,14-Eicosatetraenoic acid... 

The discovery of cannabinoid receptors naturally stimulated a search for an endogenous ligand with which the receptors naturally interact. Such a substance was isolated from the pig brain. It was found to be chemically different from plant cannabinoids it is a derivative of the fatty acid arachidonic acid (arachidonyl ethanolamide) related to the prostaglandins. This endogenous substance was named anandamide after the Sanskrit word for bliss, ananda. It has a high affinity for CBi receptors and has most of the actions of THC. 

Prostanoids, consisting of prostaglandins (PGs) and thromboxanes (TXs), are members of the lipid mediators derived enzymatically from fatty acids. Arachidonic acid, a C2o essential fatty acid for most mammalians, is freed from the phospholipid molecule by phospholipase A2, which cleaves off the fatty acid precursor. Prostanoids are produced in a wide variety of cells throughout the body from the sequential oxidation of arachidonic acid by cyclooxygenase, PG hydroperoxidase, and a series of prostaglandin synthases (Figure 2.1). 

COX-1 [Cyclo-oxygenase-1] An enzyme that catalyzes the synthesis of prostaglandins from the polyunsaturated fatty acid arachidonic acid. COX-1 is responsible for baseline levels of prostaglandins. Cyclo-oxygenase activity is inhibited by aspirin-like drugs, accounting for their antiinflammatory effects. 

Anandamide (arachidonoylethanolamide) is just one of a family of lipids known as W-acylethanolamines (NAEs), which are generated from membrane phospholipids via a common enzymatic pathway (see below). The occurrence of anandamide in an organism is dependent on (1) the presence of the fatty acid arachidonic acid as a component of membrane phospholipids and (2) the presence of enzymes that can catalyse formation of NAEs from membrane phospholipids. Therefore, the phylogenetic distribution of anandamide is likely to reflect a combination of both the phylogenetic distribution of arachidonic acid as a fatty acid component of membrane lipids and the phylogenetic distribution of the enzymes that can catalyse formation of NAEs. 

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