The effect of cigarette smoking on gastric acid secretion and gastric mucosal blood flow in man.

Smoking leads to a higher incidence of peptic ulcer and delays healing of those ulcers. Possible mechanisms include increased gastric acid secretion, reduced gastric mucosal blood flow, and reduced duodenal bicarbonate production. In six subjects we determined the effect of one hour of cigarette smoking on gastric mucosal blood flow (14C-aminopyrine clearance), acid secretion (triple lumen perfused oro-gastric tube), and plasma levels of gastrin and pancreatic polypeptide. Smoking reduced acid secretion from a median of 433 (range 160-707) mumol/min to 166 (47-340) mumol/min (p less than 0.05) and blood flow from 66 (40-70) ml/min to 36 (22-58) ml/min (p less than 0.05). There was no change in plasma gastrin and the small rise in pancreatic polypeptide would be insufficient to affect duodenal bicarbonate production. We conclude that cigarette smoking decreased gastric acid secretion and gastric mucosal blood flow. The increased incidence of gastric ulcers seen in smokers may be related to this reduction in gastric mucosal blood flow.