Histamine synthesis and gastric secretion after portacaval shunt.

In man there is an increased incidence of peptic ulcer after portacaval shunt. In the rat, 2 months after portacaval anastomosis, there is a generalized increase in the histamine content of the soft tissues, and the increase is most marked in the acid-secreting portion of the stomach. This appears to be secondary to increased activity of the histamine-synthesizing enzyme, histidine decarboxylase. A histidine decarboxylase inhibitor can prevent such hypersecretion of acid in the stomach of these animals.