Effect of gastric alkalinization on serum gastrin concentrations in humans.

Previous studies have shown that alkalinizing the stomach with sodium bicarbonate for periods up to 3 h does not cause an increase in serum gastrin concentration. We evaluated the effect of a 5-h period of continuous intragastric alkalinization on serum gastrin concentration in 12 healthy humans and 12 asymptomatic duodenal ulcer patients. On the first day, intragastric pH was maintained between 6.0 and 7.0 for 5 h by infusing 0.3 N sodium bicarbonate into the stomach. On the second day, an identical amount of sodium bicarbonate was infused intravenously while intragastric pH was permitted to remain at its natural level for 5 h. Serum gastrin concentration was also measured in each subject and patient after infusion of a homogenized steak meal. In both healthy subjects and duodenal ulcer patients, mean serum gastrin concentrations were significantly (p less than 0.05) higher after 5 h of intragastric bicarbonate infusion than after 5 h of intravenous bicarbonate infusion during which intragastric pH remained at its natural level. Increases in serum gastrin concentration with alkalinization averaged 23% and 30% of the increases in serum gastrin after a homogenized steak meal in the same subjects and patients, respectively. We conclude that continuous gastric alkalinization for 5 h increases serum gastrin concentrations in humans.