Release of somatostatin, neurotensin and vasoactive intestinal peptide upon inhibition of gastric acid secretion by duodenal acid and hyperosmolal solutions in the conscious rat.

The inhibitory effect of duodenal exposure to acid and hyperosmolal solutions on pentagastrin-stimulated gastric acid secretion was studied in conscious rats equipped with chronic gastric fistula and duodenal Thiry-Vella loop. The loop was challenged with saline, HCl or hyperosmolal polyethylene glycol. Gastric acid secretion was measured in samples from the gastric fistula. Gut peptide concentrations were measured in duodenal perfusates collected each 30 min, and in plasma samples collected both during stimulated acid secretion alone, and at the end of experiments in combination with luminal challenges of the loops. During pentagastrin-stimulated gastric acid secretion, luminal perfusion of the duodenal loop with acid caused inhibition of acid secretion (P < 0.001) and a prominent release of somatostatin both to the lumen (P < 0.001) and to the circulation (P < 0.05). Also, neurotensin (P < 0.01) and vasoactive intestinal peptide (P < 0.01) were released to the lumen, but not to the circulation. Upon perfusion of the duodenal loop with hyperosmolal polyethylene glycol, acid secretion was inhibited (P < 0.05) and somatostatin alone was released to the luminal side (P < 0.01). In conclusion, duodenal exposure to acid inhibits pentagastrin-stimulated gastric acid secretion and releases SOM to the circulation that may directly inhibit acid secretion. Concomitantly, somatostatin (SOM), neurotensin and vasoactive intestinal peptide are released to the lumen. Duodenal exposure to hyperosmolal polyethylene glycol inhibits acid secretion with a luminal release of SOM only. Thus, luminal acid and hyperosmolal solutions inhibit gastric acid secretion by separate mechanisms. After acid or hyperosmolal challenge, the release of SOM to the circulation indicates gastric acid inhibition in an endocrine manner, while a luminal release of gut peptides indicates a local peptide overflow that might be of importance via paracrine regulatory mechanisms in the intact animal.

Transforming growth factor-alpha and epidermal growth factor inhibit gastric acid secretion and stimulate release of somatostatin and neurotensin in the conscious rat.

The study compared inhibitory actions of transforming growth factor-alpha (TGF alpha) and epidermal growth factor (EGF) on gastric acid secretion and effects of these peptides on release of gut peptides considered important for acid inhibitory and gastrointestinal protective mechanisms. TGF alpha and EGF did not affect basal acid secretion, but inhibited pentagastrin-stimulated acid secretion in a dose-dependent manner from 0.10 to 1.7 nmol kg-1 h-1 i.v. by maximally 72% for TGF alpha (P < 0.001) and 76% for EGF (P < 0.001). At the highest doses, TGF alpha and EGF caused 194% and 698% increase of somatostatin-like immunoreactivity (SOM-LI) in plasma, respectively (each P < 0.05). Neurotensin-like immunoreactivity (NT-LI) increased 438% by EGF (P < 0.05), but the increase of 700% with TGF alpha did not reach statistical significance. The levels of vasoactive intestinal peptide-like immunoreactivity (VIP-LI) did not change. In gastric juice, SOM-LI increased 80% by TGF alpha i.v. (P < 0.05), but NT- and VIP-LI did not change. EGF i.v. had no effects on levels of SOM-, NT- or VIP-LI in luminal juice. Thus, TGF alpha and EGF inhibit acid secretion, but also promote the release of SOM and NT into the circulation and may be involved in the acid inhibitory effects of these growth factors.

Ten-year follow-up of a prospective, randomized trial of selective proximal vagotomy with ulcer excision and partial gastrectomy with gastroduodenostomy for treating corporeal gastric ulcer.

Between 1975 and 1980, 30 patients with type I corporeal gastric ulcer were randomly allocated to undergo selective proximal vagotomy with ulcer excision or partial gastrectomy with gastroduodenostomy. Sixteen patients underwent selective proximal vagotomy (1 was excluded from the follow-up since microscopic examination of the excised ulcer revealed an early gastric cancer) and 14 underwent partial gastrectomy. No significant differences in the clinical results were found 3 years after surgery. During a median follow-up of 10 years, ulcer recurred in 3 patients after selective proximal vagotomy and in 2 after partial gastrectomy. One patient in each group had recurrent ulcer without symptoms and received no treatment. Two selective proximal vagotomy patients and three partial gastrectomy patients had epigastric pain with or without ulcer. One patient with selective proximal vagotomy underwent a second operation because of epigastric pain and recurrent ulcer. Bowel habits remained unchanged in all but one patient in each group, and mild or moderate dumping was recorded for two patients in each group. Very good or good results (modified Visick scale) were recorded for 11 of 15 patients after selective proximal vagotomy and for 10 of 14 patients after partial gastrectomy. Except for one patient in each group who had moderate dumping, patients classified as Visick III or IV had no symptoms during treatment with antacids or H2-blockers, or had asymptomatic ulcers and needed no treatment. Selective proximal vagotomy reduced the median acid response to insulin hypoglycemia and to pentagastrin by 100% and 80%, respectively, for at least 3 to 5 years, and partial gastrectomy reduced the median acid response to pentagastrin by 97%. In our opinion, selective proximal vagotomy with ulcer excision is an alternative to partial gastrectomy for surgically treating type I gastric ulcer.

Six-year results of a prospective, randomized trial of selective proximal vagotomy with and without pyloroplasty in the treatment of duodenal, pyloric, and prepyloric ulcers.

In a consecutive series of patients with uncomplicated prepyloric, pyloric, or duodenal ulcer, 39 patients were randomly allocated to selective proximal vagotomy with pyloroplasty, and 40 patients to selective proximal vagotomy alone with no operative mortality. Before surgery, all patients had undergone H2-receptor antagonist treatment. No patient was lost for follow-up. At an average follow-up of 6 years, recurrent ulcer was recorded in 15% and 20%, respectively, after selective proximal vagotomy with and without pyloroplasty. Three of 14 recurrent ulcers were asymptomatic. Epigastric pain with or without ulcer was significantly less common after selective proximal vagotomy with (13%) than without pyloroplasty (40%). Mild diarrhea or mild dumping was recorded in a few patients. The overall results were very good or good (Visick I or II) in 77% and 55% (significant difference) after vagotomy with and without pyloroplasty, respectively, and in 82% and 58%, if asymptomatic ulcers were graded as Visick I or II results. Of the 27 patients with Visick III or IV results, three patients needed no treatment (asymptomatic ulcers), and 10 patients had no symptoms during medical treatment. Two patients with vagotomy and pyloroplasty and nine with vagotomy alone were reoperated. There were no deaths, and the results were graded as Visick I or II in 10 patients and as Visick III in one patient. The authors conclude that selective proximal vagotomy with pyloroplasty is superior to vagotomy alone for the treatment of prepyloric-pyloric and duodenal ulcer. Recurrent ulcer after vagotomy has a benign course and responds well to ranitidine treatment.