Prouroguanylin is a 112-amino-acid prohormone precursor of uroguanylin- mature biologically active 16-amino-acid peptide cleaved from its C-terminus. Guanylin binds to receptor-guanylate cyclases (CG-C) resulting in increased intracellular cGMP levels leading to CFTCR (Cystic Fibrosis Transmembrane Conductance Regulator) activation and subsequent rise in fluid and electrolyte secretion into the lumen.Prouroguanyline knock-out mice showed impaired renal excretion of external NaCl leading to elevated blood pressure independent of the level of diatary salt intake.Prouroguanylin is the predominant circulating molecular form found in circulation and in biological fluids Synonyms: Guanylate cyclase activator 2B, UGN, GCAP-II, GUCA2B.