The effect of antral distension on acid secretion and plasma gastrin in duodenal ulcer patients

The effect of antral balloon distension on acid secretion and the plasma gastrin concentration was studied in 8 duodenal ulcer patients. Antral distension significantly increased the acid secretion to about 30% of the peak acid response to pentagastrin without any change in the plasma gastrin concentration. Antral distension and concomitant intragastric neutralization, with the intention of facilitating release of antral gastrin, produced about the same acid response and did not evoke any plasma gastrin increment. The results suggest that the acid response to antral distension in duodenal ulcer patients is evoked without contribution of the gastrin mechanism, and that the acid response is probably mediated via a pyloro-oxyntic reflex. In this respect the duodenal ulcer patient seems to differ from the healthy subject, in whom antral distension produces no acid response, and from the dog, in which release of gastrin as well as pyloro-oxyntic reflex participate in the acid response to antral distension.     

Differences in antral response to meat extract in duodenal ulcer patients

Although acid secretion is important in the pathogenesis of duodenal ulcer formation, the antral phase of gastric secretion has not been adequately studied. In 60 duodenal ulcer and 12 normal patients, basal, antral and peak acid secretion was investigated. Antral function was assessed by instilling meat extract sodium and measuring acid and serum gastrin output. Two groups of patients were thus identified: 1. Antral responders in whom meat extract caused a significant increase in serum gastrin and acid output. 2. Antral nonresponders in whom meat extract did not significantly lead to an elevation in gastrin and acid output.     

Association between serum gastrin levels, gastric acid secretion and age in early gastric cancer

This study evaluated the effect of gastric acid secretion and serum gastrin response on tumor differentiation for early gastric cancer according to patients' age. We investigated the association between serum gastrin levels, gastric acid secretion and the histologic types of 335 early gastric carcinomas limited to the mucosal and submucosal layers in comparison with 450 gastric and 197 duodenal ulcers. The preoperatively examined basal acid output, maximal acid output and peak acid output after administration of tetragastrin and serum gastrin levels before and after ingestion of a test meal were determined. Patients with differentiated cancer and duodenal ulcer showed a significant negative correlation between gastric acid secretion and age, while the former group also had a significant positive correlation between serum gastrin levels and age. On the other hand, patients with undifferentiated cancer did not show any such correlation between gastric acid and age, but showed a significant positive correlation between serum gastrin, integrated gastrin response and age. Patients with gastric ulcer did not show any such correlations. These data suggest that both low acid secretion and endogenous hypergastrinemia, especially in the elderly, may play an important role in differentiated and undifferentiated gastric carcinomas.     

The role of the beta-adrnergic receptor in the secretion of gastrin: studies in normal subjects and in patients with duodenal ulcers

Intravenous infusion of isoproterenol, a beta-adrenergic receptor stimulatory agent, increased serum gastrin concentration significantly more in patients with a duodenal ulcer than in healthy subjects. The rise in pulse rate, blood glucose concentration and in serum insulin was the same in both groups of subjects. Gastrin secretion was also increased significantly more in the patients than in the control subjects after a beef-meal. Basal serum gastrin concentrations were higher in the patients than in the control subjects and correlated to the rise in serum gastrin during both tests in the patients with a duodenal ulcer. Isoproterenol and meal stimulated gastrin secretion, expressed as percent of the basal value, were twice as higher in the patients as in the control subjects. The combined administration of isoproterenol and the meal had an additive effect on the rise in serum gastrin. Isoproterenol stimulated gastrin secretion was completely suppressed by propranolol, a beta-adrenergic receptor blocking agent, which had no effect on meal stimulated gastrin secretion. It is concluded that the mechanism of the hypersecretion of gastrin in patients with a duodenal ulcer did not involve a specific abnormality of the beta-adrenergic receptor or the receptor which recognized proteins and their digested products. There is no established role of beta-adrenergic receptor activity in the hypersecretion of gastrin in patients with duodenal ulcers. It is suggested that the beta-adrenergic receptor may have some yet unknown function unrelated to the acute secretory response of gastrin.     

Percutaneous trephine lung biopsy: evolving role

In 9 normal and 42 duodenal ulcer patients, acid and gastrin studies were performed. Basal, Oxo and Histalog stimulated acid secretion was conducted on each patient. In 24 patients post vagotomy pyloroplasty or vagotomy antrectomy, these studies were repeated within three months after surgery. Two groups of duodenal ulcer patients were identified; those who did respond and those who did not respond to Oxo stimulation. In the "responders," Oxo stimulated acid output and gastrin secretion increased significantly over basal values. Both vagotomy pyloroplasty and vagotomy antrectomy caused a similar significant decrease in Oxo and Histalog stimulated acid output. In two patients with incomplete vagotomy, antrectomy, but not pyloroplasty abolished the Oxo stimulated acid response. These data suggest that OXO stimulation test can select patients with a significant antral component in whom vagotomy and antrectomy would be the appropriate procedure. Our results also indicate that antrectomy will protect against recurrent ulceration in patients with incomplete vagotomy and may explain the lower incidence of stomal ulceration in patients with vagotomy antrectomy, compared to vagotomy pyloroplasty.     

Platelet-derived growth factor BB mediated regulation of 12-lipoxygenase in porcine aortic smooth muscle cells

BACKGROUND & AIMS: Recently, we postulated a new concept of duodenal ulcer pathogenesis suggesting that antral Helicobacter pylori infection blocks inhibitory pathways to the gastrin and parietal cells, resulting in an increased and prolonged postprandial acid secretion. the aim of this study was to examine duodenal acid load and duodenal bulb pH after a meal before and after eradication of H. pylori. METHODS: Using a marker-dilution method and a pH electrode in the duodenal bulb, gastric emptying, acid secretion, gastrin release, duodenal acid load, and duodenal bulb pH were studied during 2 hours after peptone meals of pH 7.0 and 2.0 in 8 H. pylori-negative controls and 8 H. pylori-infected subjects before and 6 months after eradication. RESULTS: The H. pylori-infected subjects had an increased gastric emptying, gastrin release, and acid secretion, higher duodenal acid load, and lower duodenal bulb pH after the meals. These responses were normalized after eradication. CONCLUSIONS: H. pylori-infected subjects have an increased and prolonged postprandial acid secretion, partly caused by an impaired low pH inhibition of acid secretion, gastrin release, and gastric emptying, resulting in an increased duodenal acid load and a prolongation of low pH in the duodenal bulb, as a general prerequisite for the development of duodenal ulcer disease.     

Targeted studies as a learning tool in outcomes assessment

BACKGROUND: Gastric lipase secretion is stimulated by gastrin in plasma, but its regulation by secretin is unknown. METHODS: In 7 normal persons we investigated the effect of exogenous secretin on the output of gastric lipase stimulated by intravenous gastrin-17. The gastric content was measured using a nasogastric tube for aspiration. The quantitative lipase secretion was measured by an enzyme-linked immunosorbant assay (ELISA) and the lipolytic activity by a kinetic assay. Plasma concentrations of secretin and gastrin were measured by radioimmunoassay. RESULTS: Gastric lipase secretion (the quantity as well as the lipolytic activity) was significantly stimulated by gastrin. In response to secretin infusion, the lipolytic activity increased as acid secretion decreased. CONCLUSION: Secretin in postprandial concentrations does not influence the quantitative gastric lipase secretion stimulated by gastrin, but it increases lipolytic activity due to inhibition of acid secretion.     

Possible new mechanism for the antiparkinsonian effect of amantadine

An obese mouse model (Cpefat/Cpefat) that has hyperproinsulinemia and late onset obesity has been described. Cpefat/Cpefat mice have a missense mutation in carboxypeptidase E (CPE), a processing enzyme essential for production of biologically active endocrine and neuroendocrine peptides. We have reported previously that CPE activity was absent in the antrum of the stomach and that processing of progastrin to the amidated biologically active form of gastrin is reduced. Since gastrin is a major secretagogue for gastric acid secretion, the purpose of the present experiments was to examine gastric acid secretion in Cpefat/Cpefat mice. In addition, secretion of amidated gastrin in response to inhibition of acid secretion was tested in Cpefat/Cpefat. Both gastric acid and challenged gastrin secretion are reduced in Cpefat/Cpefat mice. We conclude that stomach CPE activity is essential for gastric secretory activity and for challenged gastrin release.     

Roles of gastrin and somatostatin in the regulation of gastric acid secretion in the fetal rabbit

In adult gastric epithelium, gastrin and somatostatin regulate parietal cell acid secretion; however, their expression and function in the fetus are largely unknown. We defined the developmental expression of gastrin and somatostatin in the fetal rabbit stomach and determined their effects on fetal acid secretion. To define peptide expression, fetuses from 12 time-mated New Zealand white rabbit does were analyzed at successive ages during the third trimester (term is 31 days). Peptides were extracted from fetal gastric tissue by boiling in water and then in acetic acid. Amidated gastrin and somatostatin levels were measured by radioimmunoassay using antisera 1296 for gastrin and 8402 for somatostatin. To determine the effects of gastrin and somatostatin, pentagastrin (64 microg/kg/hr) or octreotide (35 microg/kg/hr) were infused intravenously in conscious pregnant rabbits at 28 days of gestation for 3 hr. Fetuses (n = 45) were harvested and gastric acid was titrated with 0.02 N NaOH. Gastrin and somatostatin tissue content were 12 +/- 3 and 51 +/- 6 pmol/g at gestational day 20, respectively, and increased to 146 +/- 10 and 162 +/- 5 pmole/g by day 30 (P < 0.05). Between days 24 and 26, when gastric acid was first detectable, the molar ratio of somatostatin to gastrin decreased from 5.0 +/- 1.0 to 1.1 +/- 0.1 (P < 0.05). Fetal gastric acid content (micromole) was 28.5 +/- 1.7 in controls, 27.5 +/- 1.9 with pentagastrin treatment, and 15.8 +/- 1.4 micromole with octreotide (P < 0.05). In summary, 1) In fetal gastric tissue, gastrin increased 12-fold and somatostatin increased 3-fold between days 20 and 30 of gestation. 2) The decreased ratio of somatostatin to gastrin between days 24 and 26 of gestation coincides with the onset of fetal gastric acid secretion in the fetal rabbit. 3) Maternal administration of octreotide inhibited fetal gastric acid content; however, pentagastrin had no effect. We conclude that, in the fetal rabbit stomach, the relative expression of gastrin and somatostatin may regulate the onset of parietal cell acid secretion.     

Developmental regulation of gastric somatostatin secretion in the sheep

Gastric somatostatin (SRIF) regulates gastric acidity by inhibiting gastric acid and gastrin secretion. SRIF secretion is increased by gastric acidity and also directly by regulators of gastric acid secretion such as gastrin. This direct effect has not been described in the developing animal, nor have the roles of intermediaries such as histamine and gastric acidity been defined. The present study aimed to establish the regulatory role of gastrin and histamine during development on SRIF secretion and also to determine whether the effects of gastrin and histamine are independent of gastric pH. Pentagastrin and histamine were infused on separate occasions into fetal sheep, newborn lambs, and 28-day-old lambs. To determine the roles of endogenous histamine and gastric pH, ranitidine (a histamine-2 receptor antagonist) and omeprazole (a H+/K+ ATPase inhibitor) were coinfused with the agonists. Plasma SRIF and gastrin concentrations were measured by RIA. Pentagastrin stimulated SRIF secretion in the fetus after 131 days of gestation (term is 147 days), whereas stimulation by histamine was effective only after birth. The SRIF stimulatory effect of pentagastrin in 28-day-old lambs was abolished by ranitidine, which also reduced this effect in the adult sheep. This inhibitory effect of ranitidine was shown to be a result of blockade of stimulatory H2 receptors, because in the adult blockade of acid secretion with omeprazole failed to attenuate the response of histamine. These results indicate that in the fetus, gastrin receptors, but not histamine receptors, are functionally involved in the stimulation of SRIF secretion. After birth, both gastrin and histamine stimulate SRIF, but the effect of gastrin is mediated at least in part by the release of endogenous histamine. These responses occur independently of changes in gastric acidity, supporting the concept of a direct negative feedback between SRIF and gastrin.     

Vagal and hormonal influences on gastric secretion in duodenal ulcer disease

Current concepts on the pathophysiology of gastric hypersecretion in duodenal ulcer disease have been presented and the role of vagal nerves and gastrointestinal hormones particularly gastrin has been discussed. Duodenal ulcer patients form a heterogenous group with regard to the gastric acid and pepsin secretion and gastrin release. They may differ from healthy subjects by several wall defined defects including an increased mass of parietal and peptic cells, increased capacity to secrete acid and pepsin, increased vagal drive to the parietal cells, hyperreactivity of antrum, decreased effectiveness of antral and duodenal autoregulatory mechanisms, defective release of secretin, increased gastric emptying and defective removal of gastric acid load from the duodenum. Very little is known what proportion of duodenal ulcer patients suffer from various pathologic disturbences and what are the mechanisms underlying these changes.     

Transplantation of hepatocytes for prevention of intracranial hypertension in pigs with ischemic liver failure

BACKGROUND: How Helicobacter pylori infection affects gastric acid secretion is still unclear. METHODS: Gastric juice pH, ammonia concentration in gastric juice, serum gastrin level, and grade of gastritis in accordance with the Sydney System were determined for patients with gastric ulcer (GU) and duodenal ulcer (DU) before and after treatment with lansoprazole and amoxicillin, and results were compared with those of H. pylori-negative controls. RESULTS: Scores for H. pylori density, atrophy, metaplasia, and activity of gastritis in the corpus were higher in patients with GU, especially those with proximally located GU, than in those with DU. Gastric juice pH was significantly higher in GU patients than in DU patients and controls. After H. pylori eradication, gastric juice pH and serum gastrin levels in both GU and DU patients were significantly decreased to control levels. In patients without eradication, no significant changes in these factors were observed. CONCLUSIONS: These findings suggest that H. pylori infection and gastritis in the corpus suppress acid secretion and increase gastric juice pH, resulting in hypergastrinemia, and that eradication of H. pylori normalizes acid secretion and serum gastrin levels.     

Marked increase in gastric acid secretory capacity after omeprazole treatment

BACKGROUND: In contrast with the histamine2 (H2) blockers, proton pump inhibitors have not been shown to give rebound hypersecretion of acid. Taking into consideration the hyperplasia of the enterochromaffin-like (ECL) cell provoked by hypergastrinaemia secondary to profound acid inhibition and the central role of histamine from ECL cells in the regulation of acid secretion, the lack of any rebound acid hypersecretion after treatment with proton pump inhibitors has been questioned. AIMS: To reassess the effect of treatment with omeprazole on post-treatment acid secretion. METHODS AND PATIENTS: Basal and pentagastrin stimulated acid secretion were determined in nine patients with reflux oesophagitis before and 14 days after termination of a 90 day treatment period with the proton pump inhibitor omeprazole (40 mg daily). Basal gastrin release were determined before and during omeprazole treatment. Furthermore, biopsy samples from the oxyntic mucosa were taken before and at the end of the treatment period for chemical (histamine and chromogranin A (CgA)) evaluation of the ECL cell mass. RESULTS: A substantial increase in meal stimulated gastrin release during omeprazole treatment resulted in an increased ECL cell mass. Furthermore, CgA in serum increased during omeprazole treatment suggesting that serum CgA may be used as a test to evaluate ECL cell hyperplasia. A significant increase in basal and a marked (50%) and significant increase in pentagastrin stimulated acid secretion were found after treatment with omeprazole. CONCLUSIONS: Increased acid secretion after a conventional treatment period with a proton pump inhibitor is probably due to ECL cell hyperplasia and may have negative consequences for acid related diseases.     

Gastric acid and serum gastrin responses to insulin and 2-deoxy-d-glucose in duodenal ulcer patients before and after partial gastrectomy

Gastric acid and serum gastrin (radioimmunoassay) responses to insulin (0.2 U/kg i.v.) and 2-deoxy-D-glucose (2DG) (50 mg/kg i.v.) were determined in 11 male duodenal ulcer patients before and after partial gastrectomy involving complete antral resection. In 8 of the patients the acid response to pentagastrin (6 mug/kg subc.) was also determined. Before operation, 2DG produced higher acid and gastrin responses than insulin. Partial gastrectomy reduced basal acid secretion by 54% but did not alter the basal gastrin level, suggesting that this gastrin is of extra-antral origin. Partial gastrectomy reduced the acid responses to insulin and 2DG by 66% and 78%, respectively; after operation the acid responses to these stimulants were equal. The ratio for the acid response to insulin and pentagastrin was 65% before and 56% after partial gastrectomy; corresponding ratios for 2DG and pentagastrin were 112% and 48%. Partial gastrectomy abolished the peak gastrin response to insulin hypoglycemia and reduced that to 2DG by 64%. The integrated gastrin response to insulin and 2DG was insignificant in the operated patients. Both insulin and 2DG release mainly antral gastrin which appears to be of greater importance for the acid response to 2DG than insulin.     

Biological activity of carboxy-terminal gastrin analogs

Amidated forms of gastrin are derived by post-translational processing of a large precursor peptide and stimulate gastric acid secretion via the gastrin/CCK(B) receptor. Non-amidated biosynthetic intermediates may exert biological effects through other mechanisms, but their effect on gastric acid secretion is unclear. Amidated gastrins stimulate acid secretion mainly by releasing histamine from mucosal enterochromaffin-like cells. This study examines the effects on histamine release from the vascularly perfused rat stomach of amidated gastrin-17, COOH-terminal glycine-extended gastrin-17, gastrin-17 extended at the COOH-terminal including the remaining progastrin sequence, and carboxy-terminal progastrin fragments (SAEDEN and GRRSAEDEN). Carboxy-terminal extended gastrins induced histamine release which was inhibited by the gastrin/CCK(B) antagonist L-740,093, but had to be given in concentrations 100-fold higher than amidated gastrin-17 to produce comparable effects. These progastrin-derived peptides are found in high concentrations in some patients with the Zollinger-Ellison syndrome and may contribute to acid hypersecretion and other gastrin/CCK(B) receptor mediated responses.     

Effect of intrajejunal fat on meal-stimulated acid and gastrin secretion in man

The effect of intrajejunal fat infusion on meal-stimulated gastric acid and gastrin secretion was studied in 8 healthy volunteers. Intrajejunal fat significantly reduced the acid response to a meal, measured by intragastric titration, as compared to intrajejunal infusion of saline. While serum gastrin concentrations rose from fasting levels to a constant plateau after the meal when saline was infused, fat infusion resulted in a transitory decrease in serum gastrin concentration followed by a significant increase. It is concluded that inhibition of gastrin release only plays a minor role, if any, in the observed fat-induced jejuanl inhibition of meal-stimulated acid secretion.     

Effects of ranitidine bismuth citrate on gastric acid secretion and gastrin release in subjects with and without Helicobacter pylori infection

BACKGROUND: Ranitidine bismuth citrate is a novel antiulcerant that provides the antisecretory activity of ranitidine and the gastric mucosal protection and antibacterial properties of bismuth. METHODS: This randomized, double-blind, placebo-controlled study evaluated the effects of single doses of ranitidine bismuth citrate 200 mg, 400 mg and 800 mg and ranitidine hydrochloride 150 mg on gastrin release and suppression of gastric acid secretion, and compared acid secretory profiles and gastrin release between Helicobacter pylori-negative and -positive patients. Plasma gastrin concentrations were determined by radioimmunoassay under basal conditions and in response to peptone meal stimulation. Acid secretion was measured under basal conditions and in response to peptone meal stimulation. Presence of H. pylori was determined by both 14C-urea breath test and ELISA serology. RESULTS: Inhibition of gastric acid output by ranitidine bismuth citrate was both time- and dose-dependent over the 9-h post-dose study period. Doses of ranitidine bismuth citrate 400 mg and ranitidine hydrochloride 150 mg, which are equimolar, produced similar suppression of acid output regardless of H. pylori status. Ranitidine bismuth citrate had no effect on plasma gastrin concentrations regardless of H. pylori status. All doses of ranitidine bismuth citrate were well tolerated. CONCLUSIONS: Ranitidine bismuth citrate caused time- and dose-dependent reductions in meal-stimulated and between-meal gastric acid output regardless of H. pylori status. The magnitude of decreased acid secretion was similar with ranitidine bismuth citrate 400 mg and ranitidine hydrochloride 150 mg. Ranitidine bismuth citrate had no effect on plasma gastrin concentrations.     

Rebound hypersecretion after omeprazole and its relation to on-treatment acid suppression and Helicobacter pylori status

BACKGROUND & AIMS: There have been conflicting reports regarding acid secretion after treatment with omeprazole. This study examined acid secretion after treatment with omeprazole and its relation to Helicobacter pylori status and on-treatment gastric function. METHODS: Twelve H. pylori-negative and 9 H. pylori-positive subjects were examined before, on, and at day 15 after an 8-week course of 40 mg/day omeprazole. On each occasion, plasma gastrin, intragastric pH, and acid output were measured basally and in response to increasing doses of gastrin 17. RESULTS: In the H. pylori-negative subjects at day 15 after omeprazole treatment, basal acid output was 82% higher (P < 0.007) and maximal acid output 28% higher (P < 0.003) than before omeprazole. The degree of increase in maximal acid output was related to both on-treatment pH and on-treatment fasting gastrin levels, being 48.0% in subjects with an on-treatment pH of >4 vs. 21. 0% in those with a pH of <4 (P < 0.02) and 49.2% in subjects with an on-treatment gastrin of >25 ng. L-1 vs. 19.8% in those with a fasting gastrin of <25 ng. L-1 (P < 0.006). At day 15 after omeprazole treatment, the H. pylori-positive subjects showed a heterogeneous response with some having increased acid output and others persisting suppression. CONCLUSIONS: Rebound acid hypersecretion occurs in H. pylori-negative subjects after omeprazole treatment. Its severity is related to the degree of elevation of pH on treatment. Persisting suppression of acid secretion masks the phenomenon in H. pylori-positive subjects.     

Gastric ulcer: effect of healing on gastric acid secretion and fasting serum gastrin levels

In 15 patients with uncomplicated gastric ulcers, basal and peak gastric acid outputs and fasting serum gastrin levels were studied before and after healing. The mean basal acid output [4.0 +/- 1.3 (SEM) mEq H+/hr], the mean peak acid output (29.5 +/- 5.1 mEq H+/hr), and the mean fasting serum gastrin level (80.3 +/- 16.7 pg/ml) in these patients did not change significantly with healing. Failure of gastric secretory function to change with healing suggests that mucosal resistance factors are more important than gastric acid secretion in the pathogenesis of a gastric ulcer.     

The fine structure of fins and finrays of Tilapia mossambica (Peters)

Gastrin release and gastric acid secretion were induced by electrical stimulation of the vagi in anesthetized cats. No correlation was found between the peripheral gastrin levels and the magnitudes of the concomitant secretory responses. In experiments in which a high rate of secretion was induced the peripheral gastrin levels were found to be unchanged or at most slightly elevated, whereas the levels were sometimes substantially elevated in animals in which there was little or no acid secretory response. An arterio-venous difference in gastrin levels was detected in the corpus blood during periods of gastric secretion. This clearance of gastrin (104-540 pg/min) was large enough to influence the peripheral gastrin levels. The mechanism behind and the significance of the gastric clearance of gastrin is discussed.