G protein-coupled receptors (GPRs) are a protein family of transmembrane receptors that transmit an extracellular signal (ligand binding) into an intra cellular signal (G protein activation). GPR signaling is an evolutionarily ancient mechanism used by all eukaryotes to sense environmental stimuli and mediate cell-cell communication. All of the receptors have seven membrane- spanning domains and the extracellular parts of the receptor can be glycosylated. These extracellular loops also contain two highly conserved cysteine residues which create disulfide bonds to stabilize the receptor structure. GPR119 is a 335 amino acid protein that is mainly expressed in the pancreas. It is an endogenous receptor for lysophosphatidylcholine (LPC), which is is a lipid mediator involved in insulin secretion from pancreatic ? cells. GPR119 may participate in this insulin secretion, suggesting that it may be potential target for new anti-diabetic drugs.