Role of Urease in the Gastric Mucosa

Abstract

Studies of the effect on gastric secretion of injns. of urea into the blood supply of the histamine-stimulated dog with its stomach isolated by ligation at the cardiac and pyloric ends have shown that (1) the concn. of gastric juice ammonium ion was a function of the plasma urea concn. and the gastric ammonia was derived from the plasma urea through gastric urease action; (2) the concn. of ammonium N in the gastric juice was less than half that of urea nitrogen in the plasma; (3) gastric juice acidity and pH were essentially unaltered under the conditions of the expts. at plasma urea N levels as high as 80 mg. %;(4) only traces of urea appeared in the gastric juices. Apparently gastric urease regulates the acidity of the secretion but slightly under normal conditions, but it might influence it in conditions of very high plasma urea concn. The gastric urease might have a protective intramucosal function in providing ammonia for neutralization of acid in particular histological regions.