Inhibition of gastric acid secretion by a glycoprotein isolated from human urine (human urinary gastric inhibitor).

The gastric antisecretory activity of an inhibitor newly isolated from human urine (Human Urinary Gastric Inhibitor or HUGI) has been studied. HUGI was given intravenously and its activity determined in the following test systems: gastric secretion in the rat with pyloric ligation; gastric secretion in the dog with a Heidenhain pouch stimulated with pentagastrin, histamine and a protein meal; acid secretion by the isolated gastric mucosa of the rat; gastrointestinal motility; bile flow and gall-bladder tone and arterial and venous blood pressure and heart rate. HUGI was found to have marked activity only in the pyloric-ligated rats and in the dogs with Heidenhain pouches stimulated by a protein meal. Particularly in the dog, HUGI (0.1 to 6.4 micrograms/kg, i.v) markedly inhibited gastric secretion, dose-dependently and without changing the plasma gastrin concentration. Negative results were obtained in the other tests, but these results serve to demonstrate that HUGI is an inhibitor well-differentiated from other glycoproteins or peptides with gastric antisecretory activity, such as urogastrone and GIP. The results obtained to date are not sufficient to allow the mechanism of action of HUGI to be defined.