Neuropeptide RFRP-1 acts as a potent negative regulator of gonadotropin synthesis and secretion. Neuropeptides NPSF and NPVF efficiently inhibit forskolin-induced production of cAMP, but RFRP-2 shows no inhibitory activity. Neuropeptide RFRP-1 induces secretion of prolactin in rats. Neuropeptide NPVF blocks morphine-induced analgesia.