Uroguanylin

Where it comes from

Made in

Enterochromaffin cells of the duodenum and small intestine; also found in urine

Sent out by

After salty meals; it works in the acid duodenum where guanylin does not

Acts on

• Small-intestinal epithelium
• Kidney (sodium excretion)
• Hypothalamus (satiety, in mice)

What it does

• Secretes fluid and bicarbonate in the upper gut ¹
• Tells the kidney to shed sodium after a salty meal ¹
• Signals fullness in mice; not confirmed in people ³

In medicine

• Plecanatide is uroguanylin with one amino acid changed, approved for chronic constipation and IBS with constipation ²
• No clinical test measures it; the assays are difficult because the peptide is small, bridged and present in tiny amounts ¹

Beyond the body’s own use

• Its satiety role came from mice, where uroguanylin made in the gut reached the hypothalamus and cut food intake, and where deleting the receptor made the animals eat more ³. No human data followed and no obesity medicine came of it
• Low uroguanylin is reported in obesity, which would fit that story, but the measurements are hard and nothing shows which way the cause runs ¹