EFFECT OF GASTRIC STIMULANTS ON HISTAMINE-RELEASE AND CIRCULATORY RESPONSES

The effects of pentagastrin (6-mu-g/kg/h) or insulin (0.15 U/kg/h) on histamine release and blood circulation in nine anaesthetized dogs were studied by measuring (1) plasma histamine Concentrations in the iliac artery, iliac vein, hepatic vein and portal vein, (2) the corresponding blood pressures, and (3) blood flow in the hepatic artery and the portal vein. In the portal vein, pentagastrin induced an overall 204% rise (p < 0.01) in plasma histamine and a 28% rise (p < 0.01) in blood flow while other measurements did not change significantly. Insulin did not induce similar rises. Three patients with duodenal ulcer (DU) undergoing proximal gastric vagotomy (PGV) were given pentagastrin (6-mu-g/kg) by bolus injection. Plasma histamine concentrations in the gastric veins draining the oxyntic cell area rose by 68%, 15 min after injection. Thus, specific histamine release may act as a mediator for pentagastrin-stimulated gastric acid secretion and as a vasodilator to facilitate gastric circulation. Insulin did not promote histamine release in the present study.