Uroguanylin is a 16 amino acid peptide that is secreted by enterochromaffin cells in the duodenum and proximal small intestine.
Guanylin acts as an agonist of the guanylyl cyclase receptor guanylate cyclase 2C (GC-C), and regulates electrolyte and water transport in intestinal and renal epithelia.
By agonizing this guanylyl cyclase receptor, uroguanylin and guanylin cause intestinal secretion of chloride and bicarbonate to dramatically increase; this process is helped by the second messenger cGMP.
In humans, the uroguanylin peptide is encoded by the GUCA2B gene.
[2][3] Uroguanylin may be involved in appetite and perceptions of 'fullness' after eating meals, as suggested by a study into mice.