Current Understanding of Guanylin Peptides Actions

Abstract

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.

Metabolic responses to xenin-25 are altered in humans with Roux-en-Y gastric bypass surgery

“…The loss of this inhibitory pathway could play an important role in the exaggerated postprandial GLP-1 release after RYGB. Intriguingly, guanylin peptide is produced in the same region of the bowel as GLP-1, causes diarrhea, and is secreted in response to neural input [44–47]. Thus, altered neural signaling to distal bowel could also explain the reduction in diarrhea in the RYGB group.…”

Absorption, Transport, and Retention

“…Bile is an alkaline liquid that is yellow, green, brown, or nearly black (Sutor and Wilkie, 1976). Bile that has been stored in the gallbladder is significantly more concentrated than freshly secreted bile.…”

Development of an enterotoxigenic Escherichia coli vaccine based on the heat-stable toxin

“…18,31,32 An additional receptor for guanylin and uroguanylin has been identified, namely GC-D, which is exclusively expressed in olfactory neurons. 33,34 In kidneys, however, guanylin and uroguanylin act primarily through GC-C independent receptors that are not yet identified. 35 The structure of a fully toxic truncated synthetic STp analog, where C5 was substituted with β-mercaptopropionic acid, was solved by X-ray crystallography in 1991.…”