The inhibitory effects of
intravenous infusions of
secretin,
glucagon and
caerulein on the gastric acid response to
bombesin were studied in 8
duodenal ulcer patients.
Bombesin was found to be a very potent stimulator of gastric acid secretion in patients with
duodenal ulcer. There were no significant differences in
acid outputs per 15-min period between
bombesin infused in a dose of 0.9 microgram/kg/h and
pentagastrin infusion administered in a maximal dose, at a rate of 6.0 microgram/kg/h.
Secretin (1 U/kg/h),
glucagon (30 microgram/kg/h) and
caerulein (0.1 microgram/kg/h) produced significant decreases in gastric acid secretion evoked by
bombesin given in a dose of 0.9 microgram/kg/h. Percentages of inhibition were 48.6, 45.2 and 35.5, respectively. It is supposed that
secretin and
glucagon given in pharmacological doses are capable of interfering with the action of
gastrin released from antrum by means of
bombesin on the parietal cell by noncompetitive kinetics.
Caerulein administered in a pharmacological dosis, however, can inhibit the effect of
gastrin released by
bombesin on the parietal cells by a competitive kinetic.