GPR103 is a G-protein coupled receptor that has been shown to be expressed primarily in brain, heart, kidney, adrenal gland, retina and testis. Its ligand has been identified as a 43-residue RF-amide peptide known as QRFP. When administered centrally in mice, QRFP was shown to increase feeding, behavioral arousal and blood pressure. When administered iv, this peptide caused release of aldosterone. Knockout mice (GPR103 -/-) have suggested a role of GPR103 in regulating bone formation. These diverse but important physiological functions of this receptor and ligand make them important possible targets for drug discovery in several fields.