Inhibition of gastrin release induced by fundic distension. Evidence of a defective inhibition in duodenal ulcer patients.

The serum gastrin response to an infusion of gastrin-releasing peptide (GRP), with or without simultaneous fundic distension, was studied in healthy volunteers and in patients with duodenal ulcer disease before and after a complete proximal gastric vagotomy (PGV). We also studied the effect of fundic distension alone on gastrin release and intraluminal gastric pressure in healthy volunteers and in patients after PGV. We observed an increased intraluminal pressure in patients after PGV compared with healthy subjects. During fundic distension with 600 ml of air no significant increase in gastrin values was observed in healthy subjects or in duodenal ulcer patients. In healthy subjects fundic distension significantly inhibited the gastrin response to the higher dose of GRP. This inhibitory effect exerted by fundic distension was counteracted by cholinergic blockade. In contrast, fundic distension did not alter the gastrin response to GRP in duodenal ulcer patients, suggesting a defective inhibitory mechanism in duodenal ulcer patients. After PGV, GRP infusion resulted in an enhanced gastrin response, and fundic distension seemed to facilitate the gastrin-stimulatory effect of GRP. This supports the concept of a vagally dependent inhibitory oxyntopyloric mechanism and that fundic distension can elicit both inhibitory and stimulatory secretory mechanisms.