RFRP-3 (Neuropeptide VF(124-131))(human), a human GnIH peptide homolog, is a potent inhibitor of gonadotropin secretion by inhibiting Ca2+ mobilization. RFRP-3(human) is a NPFF1 receptor agonist, it inhibits forskolin-induced production of cAMP with an IC50 of 0.7 nM.