Regulatory peptides
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Regulatory peptides · May 1999
ReviewGuanylin regulatory peptides: structures, biological activities mediated by cyclic GMP and pathobiology.
The guanylin family of bioactive peptides consists of three endogenous peptides, including guanylin, uroguanylin and lymphoguanylin, and one exogenous peptide toxin produced by enteric bacteria. These small cysteine-rich peptides activate cell-surface receptors, which have intrinsic guanylate cyclase activity, thus modulating cellular function via the intracellular second messenger, cyclic GMP. Membrane guanylate cyclase-C is an intestinal receptor for guanylin and uroguanylin that is responsible for stimulation of Cl- and HCO3- secretion into the intestinal lumen. ⋯ Lymphoguanylin is also produced in cells of the lymphoid-immune system where other physiological functions may be influenced by intracellular cyclic GMP. Observations of nature are providing insights into cellular mechanisms involving guanylin peptides in intestinal diseases such as colon cancer and diarrhea and in chronic renal diseases or cardiac disorders such as congestive heart failure where guanylin and/or uroguanylin levels in the circulation and/or urine are pathologically elevated. Guanylin peptides are clearly involved in the regulation of salt and water homeostasis, but new findings indicate that these novel peptides have diverse physiological roles in addition to those previously documented for control of intestinal and renal function.