Arachidonic Acid, 500mg

Arachidonic Acid is an essential fatty acid. Occurs in liver, brain, glandular organs, and depot fats of animals, in small amounts in human depot fats, and is a constituent of animal phosphatides. Arachidonic Acid is a precursor in the biosynthesis of prostaglandins, thromboxanes, and leukotrienes. Arachidonic acid plays a key role in cellular regulation and is controlled through multiple interconnected pathways. Arachidonic acid (AA) is an unsaturated ω6 fatty acid constituent of the phospholipids of cell membranes. Phospholipase A2 releases AA from the membrane phospholipids in response to inflammation. AA is subsequently metabolized to prostaglandins and thromboxanes by at least two cyclooxygenase (COX) isoforms, to leukotrienes and lipoxins by lipoxygenases, and to epoxyeicosatrienoic acids via cytochrome p450-catalyzed metabolism. AA and its metabolites play important roles in a variety of biological processes, including signal transduction, smooth muscle contraction, chemotaxis, cell proliferation and differentiation, and apoptosis. AA has been demonstrated to bind to the a subunit of G protein and inhibit the activity of Ras GTPase-activating proteins (GAPs). Cellular uptake of AA is energy dependent and involves protein-facilitated transport across the plasma membrane. If ethanol is undesirable, arachidonic acid may be dissolved in acetonitrile, DMF, or DMSO. Simply evaporate the ethanol under a gentle stream of nitrogen (be certain not to evaporate the material to dryness) and redissolve the arachidonic acid in the solvent of choice. Just prior to use, make dilutions of the stock solution into aqueous buffer or isotonic saline to bring the arachidonic acid to the desired concentration. Ensure that the residual amount of organic solvent is insignificant, since organic solvents may have physiologic effects at low concentrations. A control using the solvent in the absence of the prostaglandin will address this potential variable. We do not recommend storing the aqueous solution for more than one day. It is difficult to obtain aqueous solutions of arachidonic acid directly. However, an organic solvent free solution of arachidonic acid can be prepared using concentrated basic buffers (pH > 8.0 and ionic strength not less than 0.1 M). Add 400 μL of cold buffer (0°C) per mg of arachidonic acid and agitate vigorously and/or ultrasonicate.