guanylin

Guanylin is an endogenous peptide hormone that acts as a ligand for the receptor guanylate cyclase C (GC-C), primarily expressed on the apical membrane of intestinal mucosal cells. Its activation of GC-C leads to the production of intracellular cyclic guanosine monophosphate (cGMP), which subsequently activates protein kinase G II (PKGII) and the cystic fibrosis transmembrane conductance regulator (CFTR). This signaling pathway is crucial for regulating intestinal fluid and electrolyte balance, maintaining intestinal pH, and preventing hypernatremia. Guanylin also plays a role in maintaining the hydrated state of colonic mucus, influencing commensal microorganisms and bowel clearance. Dysregulation of the GC-C/cGMP signaling axis, including loss of guanylin expression, is implicated in various conditions such as functional gastrointestinal disorders, inflammatory bowel disease, visceral pain, and colorectal cancer, making the GC-C pathway a promising therapeutic target.