The GPR40 and GPR120 receptors are also known as the Free Fatty Acid Receptor (1 and 4 respectively). All of them are members of the A11 subfamily of GPCR receptors. Four (1-4) subtypes of the FFA receptors are known to date. They are a critical component of the body’s nutrient sensing apparatus, and small molecule agonists and antagonists of these receptors show considerable promise in the management of diabetes and its complications. Unlike the classic ‘lock and key’ relationship between receptors and their ligands, nutrient receptors are considered to be promiscuous in that they can be activated by a range of ligands.
 Free fatty acid receptors: emerging targets for treatment of diabetes and its complications V. Vangaveti, V. Shashidhar, G. Jarrod, B.T. Baune, R.L. Kennedy. Ther. Adv. Endocrinol. Metab. 2010, 1, 165-175