%0 Journal Article
%T Current Understanding of Guanylin Peptides Actions
%A Aleksandra Sindic
%J ISRN Nephrology
%D 2013
%R 10.5402/2013/813648
%X Guanylin peptides (GPs) family includes guanylin (GN), uroguanylin (UGN), lymphoguanylin, and recently discovered renoguanylin. This growing family is proposed to be intestinal natriuretic peptides. After ingestion of a salty meal, GN and UGN are secreted into the intestinal lumen, where they inhibit sodium absorption and induce anion and water secretion. At the same conditions, those hormones stimulate renal electrolyte excretion by inducing natriuresis, kaliuresis, and diuresis and therefore prevent hypernatremia and hypervolemia after salty meals. In the intestine, a well-known receptor for GPs is guanylate cyclase C (GC-C) whose activation increases intracellular concentration of cGMP. However, in the kidney of GC-C-deficient mice, effects of GPs are unaltered, which could be by new cGMP-independent signaling pathway (G-protein-coupled receptor). This is not unusual as atrial natriuretic peptide also activates two different types of receptors: guanylate cylcase A and clearance receptor which is also G-protein coupled receptor. Physiological role of GPs in other organs (liver, pancreas, lung, sweat glands, and male reproductive system) needs to be discovered. However, it is known that they are involved in pathological conditions like cystic fibrosis, asthma, intestinal tumors, kidney and heart failure, obesity, and metabolic syndrome. 1. Introduction The physiological importance of digestive system is not only to digest and absorb nutrients but also to prepare the body for an increase in blood concentrations of glucose, amino acids, electrolytes, and water. It is well known that several hormones secreted by intestine after a meal, like gastrin, secretin, cholecystokinin, and especially gastric inhibitory peptide increase insulin production even before the concentrations of glucose and amino acids significantly increase in the blood. Lennane et al. in 1975 showed that salt taken per os will increase secretion of electrolyte and water by the kidneys more than the same amount of the salt given intravenously, proposing the existence of intestinal hormones that regulate kidney function [1]. After a salty meal, intestinal natriuretic peptides also known as guanylin peptides (GPs) are secreted by intestine where the inhibit sodium absorption from intestinal lumen by inhibiting sodium/hydrogen exchange (NHE), increase bicarbonate and chloride secretion, inhibit water absorption [2, 3], and increase renal sodium and potassium secretion [4¨C6]. Effects of GPs on sodium transport in the intestine and the kidneys prevent postprandial hypernatremia, gastric
%U http://www.hindawi.com/journals/isrn.nephrology/2013/813648/