gnih is a neurohormone classified as an rfamide (rfa) or rfamide-related peptide (rfrp), coded by the npvf gene in mammals. the complete amino acid sequence varies by species, but all rfa and rfrp peptides contain an arginine-phenylalanine-amine sequence at the c-terminal. this is seen in both coturnix japonica gnih rfa (ser-ile-lys-pro-ser-ala-tyr-leu-pro-leu-arg-phe-nh2), and the human homolog, rfrp-3 (val-pro-asp-leu-pro-glu-arg-phe-nh2).