THE GUANYLIN AND UROGUANYLIN PEPTIDE-HORMONES AND THEIR RECEPTORS

Guanylin and uroguanylin are newly discovered, related peptides that a ctivate common guanylyl cyclase signaling molecules and via 3',5'-guan osine cyclic monophosphate regulate the activity of a variety of tissu es and organs. Additionally, the message for both peptides is expresse d in a variety of tissues and organs including the intestinal tract an d kidney and thus may serve RS part of a functional endocrine axis lin king these two major organ systems in fluid/volume homeostasis. This m anuscript reviews the discovery and nature of the guanylin and uroguan ylin peptides, their actions on the intestinal mucosa and kidney, the distribution and molecular biology of the guanylyl cyclase C receptor, and explores the future directions of this rapidly developing, expand ing field of inquiry.