Free Fatty Acid Receptor Antibodies

Free fatty acid receptors (FFA) are activated by free fatty acids. Long-chain saturated and unsaturated fatty acids including myristic acid, palmitic acid, oleic acid, linoleic acid and arachidonic acid activate FFA1 and FFA4 receptors, while short chain fatty acids including acetic acid, propanoic acid, butyric acid and pentanoic acid activate FFA2 and FFA3 receptors. In addition, GPR84 is putatively activated by medium-chain fatty acids. Long-chain fatty acids are thought to reach levels of 0.01-10 μM in the circulation, mainly being products of dietary intake, adipose recycling and hepatic turnover of neutral fats. Short chain fatty acids are generated during fermentation of resistant starches and indigestible fiber by anaerobic gut flora and can reach millimolar concentrations in the hind-gut. Short chain fatty acids can also be generated as metabolic byproducts of anaerobic bacteria and following alcohol ingestion. The concentration of total short chain fatty acids in human peripheral blood is 50-100 μM and 300-450 μM in portal blood.  It is possible that, rather than being redundant, that receptor tissue distribution combined with local fatty acid levels and their carbon chain-lengths and degree of saturation will determine the physiological role of the receptors. The role of FFA1 is best understood due to the phenotyping of transgenic mice and identification of selective small-molecule agonists and an antagonist. With the central role that fatty acids play in metabolism and other physiological functions including regulation of the immune response, the FFA receptor family currently provide a key focus for development of novel therapeutic agents.