QRFP is a 26-amino acid peptide (QRFP-26) that, widely distributed among vertebrates, is a member of the RF amide peptide family harboring the arginine-phenylalanine-amide (Arg-Phe-NH₂) sequence motif in their carboxyl terminal. It is the cognate ligand of the human orphan receptor GPR103, a G protein-coupled receptor. Like other members of the super family, QRFP receptor has an extracellular N-terminal tail and intracellular C-terminus.

Its QRFP N-terminus binds with high affinity to GPR103 and has the efficacy to inhibit cAMP synthesis. QRFP has been shown to affect locomotor activity, energy homeostasis, reproduction, bone formation, blood pressure, hormone regulation, nociception, and appetite stimulation.

QRFP expressing neurons have shown to be expressed in various hypothalamic nuclei including the ventromedial hypothalamic nucleus, the lateral hypothalamic area, retrochiasmatic area and the arcuate nucleus^1,2. The receptor is detected in the CNS and in peripheral tissues, notably in bone, heart, kidney, pancreas and testis.

Increasing data suggest the ligand/receptor system plays an important role in the regulation of food intake and glucose homeostasis¹.