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Serum gastrin and gastrin-immunoreactive cells in the antral mucosa of patients with alcoholic liver disease.

BACKGROUND/AIMS: Hypergastrinaemia has been reported in liver cirrhosis; meanwhile, it is unclear whether it is associated with an increase in gastrin cell function. The serum gastrin concentration and the number of gastrin cells in antral biopsies were studied in patients with alcoholic liver disease. METHODS: Immunocytochemical and quantification techniques were used to localize and determine the number of gastrin cells. RESULTS: Slight non-significantly higher serum gastrin values were observed in the alcoholic liver disease patients compared with controls, but the individual variation within the groups was considerable. The frequency of gastrin cells did not differ between groups. However, the size of the gastrin cell nuclei was larger in patients with liver disease than in controls, indicating increased cellular activity. CONCLUSIONS: Alcoholic liver disease, with a disturbed liver function, influences the gastrin cells. The observed alterations may reflect the effect of alcohol and/or malnutrition, or may be secondary to the influence of liver disease on other regulatory peptides.

Adult↗

Aging and gastrin production: changes in serum and antral gastrin concentrations in the rat.

Serum gastrin concentration and antral gastrin content were measured in 4-5- and 26-28-mo rats under fed conditions, after 3 days of starvation, and after 1 day of refeeding after starvation, to determine whether gastrin homeostasis is altered during aging. Gastric weight was 29% greater, but antral weight and DNA were less in the older rats. Serum gastrin fell during starvation and rose during refeeding in both groups, but it was lower in aging rats only during refeeding. Antral gastrin content in older animals was 60% of that in young rats. Starvation reduced antral gastrin only in the young, whereas refeeding lowered antral gastrin in the older animals. We conclude that, in aging rats, the relationship of serum and antral gastrin is altered during changes in food intake.

Aging↗

Serum gastrin in Zollinger-Ellison syndrome: II. Prospective study of gastrin provocative testing in 293 patients from the National Institutes of Health and comparison with 537 cases from the literature. evaluation of diagnostic criteria, proposal of new criteria, and correlations with clinical and tumoral features.

In two-thirds of patients with Zollinger-Ellison syndrome (ZES), fasting serum gastrin (FSG) levels overlap with values seen in other conditions. In these patients, gastrin provocative tests are needed to establish the diagnosis of ZES. Whereas numerous gastrin provocative tests have been proposed, only the secretin, calcium, and meal tests are widely used today. Many studies have analyzed gastrin provocative test results in ZES, but they are limited by small patient numbers and methodologic differences. To address this issue, we report the results of a prospective National Institutes of Health (NIH) study of gastrin provocative tests in 293 patients with ZES and compare these data with those from 537 ZES and 462 non-ZES patients from the literature. In 97%-99% of gastrinoma patients, an increase in serum gastrin post secretin (Delta secretin) or post calcium (Delta calcium) occurred. In NIH ZES patients with <10-fold increase in FSG, the sensitivity/specificity of the widely used criteria were as follows: Delta secretin > or =200 pg/mL (83%/100%), Delta secretin >50% (86%/93%), Delta calcium > or =395 pg/mL (54%/100%), and Delta calcium >50% (78%/83%). A systematic analysis of the sensitivity and specificity of other possible criteria for a positive secretin or calcium test allowed us to identify a new criterion for secretin testing (Delta > or =120 pg/mL) with the highest sensitivity/specificity (94%/100%) and to confirm the commonly used criterion for calcium tests (Delta > or =395 pg/mL) (62%/100%). This analysis further showed that the secretin test was more sensitive than the calcium test (94% vs. 62%). Our results suggest that secretin stimulation should be used as the first-line provocative test because of its greater sensitivity and simplicity and lack of side effects. In ZES patients with a negative secretin test, 38%-50% have a positive calcium test. Therefore the calcium test should be considered in patients with a strong clinical suspicion of ZES but a negative secretin test. Furthermore, we found that some clinical (diarrhea, duration of medical treatment), laboratory (basal acid output), and tumoral (size, extent) characteristics correlate with the serum gastrin increase post secretin and post calcium. However, using the proposed criteria, the result of these provocative tests (that is, positive or negative) is minimally influenced by these factors, so secretin and calcium provocative tests are reliable in patients with different clinical, laboratory, and tumor characteristics. A systematic analysis of meal testing showed that 54%-77% of ZES patients have a <50% postprandial serum gastrin increase. However, 9%-20% of ZES patients had a >100% increase post meal, causing significant overlap with antral syndromes. Furthermore, we could not confirm the usefulness of meal tests for localization of duodenal gastrinomas. We conclude that the secretin test is a crucial element in the diagnosis of most ZES patients, the calcium test may be useful in selected patients, but the meal test is not helpful in the management of ZES. For secretin testing, the criterion with the highest sensitivity and specificity is an increase of > or =120 pg/mL, which should replace other criteria commonly used today.

Calcium↗

The metabolism of gastrin-52 and gastrin-6 in pigs.

The kinetics and metabolism in various organs of three bioactive products of progastrin, the small sulfated and nonsulfated gastrin-6 and the large nonsulfated gastrin-52, were examined during intravenous administration in anesthetized pigs. The kidney, hindlimb, liver, head, and gut eliminated the hexapeptides efficiently, with a fractional extraction ranging from 0.50 to 0.28 (P<0.001-0.05). No metabolism was recorded in the lungs, and sulfation was without influence on the extraction of gastrin-6. Gastrin-52 was eliminated only in the kidney and the head, with a fractional extraction between 0.23 and 0.11 (P<0.01-0.05). The half-life of sulfated and nonsulfated gastrin-6 was 1.5+/-0.4 and 1.4+/-0.3 min, the metabolic clearance rate (MCR) was 80.8+/-7.6 and 116.0+/-13.5 ml x kg(-1) x min(-1) (P<0.05), and the apparent volume of distribution (V(dss)) was 199.3+/-70.1 and 231.4+/-37.3 ml/kg, respectively. The decay of gastrin-52 in plasma was biexponential. The half-lives of this biexponential after a bolus injection were 3.9+/-0.5 (T(1/2alpha)) and 25.7+/-1.4 (T(1/2beta)) min, and the MCR and V(dss) were 4.2+/-0.4 ml. kg(-1) x min(-1) and 116.2+/-16.2 ml/kg(1). We conclude that there is a differential elimination of progastrin products in splanchnic and nonsplanchnic tissue, which depends on the chain length of the peptides. Sulfation of gastrin-6 had no influence on the organ-specific extraction but reduced the MCR. Our results are in keeping with previous studies of nonsulfated gastrin-17, which is extracted in the kidney, head, limb, and gut but not in the liver.

Anesthesia↗

[Is there a feed-back mechanism between serum gastrin concentration and gastrin release (author's transl)].

The dialysability of gastrin heptadecapeptide was investigated in a model arrangement. The amounts of gastrin passing through the dialysis membrane during a 6-hour dialysis procedure are very small. Furthermore, the serum gastrin concentrations were measured during a 6-hour haemodialysis session with and without simultaneous pentagastrin infusion (0.003 mug/kg/h) in 8 patients on intermittent haemodialysis. There is a continuous decrease in the serum gastrin concentration during the 6-hour dialysis period with simultaneous pentagastrin infusion, while in the investigation without pentagastrin infusion phases of increase in serum gastrin levels are observed. In view of this different response of the serum gastrin curve it is suggested that a direct feed-back mechanism exists between the serum gastrin concentration and gastrin release, a mechanism which was interrupted by the pentagastrin infusion in the present investigation.

Feedback↗

Antiproliferative effects of gastrin receptor antagonists and antibodies to gastrin on human colon carcinoma cell lines.

The gastrointestinal hormone gastrin has been shown to stimulate the growth of normal colonic mucosa. To examine for a possible role of gastrin in the proliferation of cultured colon tumor cells, we have studied the effects of two gastrin receptor antagonists, proglumide and benzotript, and of antibodies to gastrin. We find that proglumide (50% effective concentration, 2 to 5 mM) and benzotript (50% effective concentration, 0.4 to 0.8 mM) inhibit the monolayer growth of six human colon cancer cell lines. Addition of exogenous gastrin abrogated the growth-inhibitory effect of proglumide. The anchorage-independent growth of colon carcinoma cells was also inhibited by the two gastrin antagonists. Also, a dose-dependent increase in carcinoembryonic antigen secretion was observed upon treatment with proglumide and benzotript in three cell lines examined. Half-maximal inhibition of labeled gastrin binding was observed at concentrations of 0.4 mM benzotript and 8.6 mM proglumide. In addition, antigastrin antiserum added to HCT 116 cells adapted to growth in serum-free medium resulted in a concentration-dependent inhibition of cellular proliferation. These data suggest that gastrin may function as an autocrine growth factor in colon carcinoma.

Antibodies↗

Plasma gastrin responses to bombesin and antral gastrin concentrations in patients with the intestinal type of gastric cancer.

Mucosal atrophy of the gastric antrum (type B atrophic gastritis) is generally accepted as predisposing to the development of the intestinal type of gastric cancer. Since bombesin stimulates gastrin release selectively from the antral mucosa, the response can be used as a marker for antral mucosal atrophy. In this study we have investigated bombesin-stimulated plasma gastrin responses in 21 patients with the intestinal type of gastric cancer and we have compared the results with 12 patients with the diffuse type of gastric cancer, 17 patients with benign gastric ulcer, and 30 dyspeptic patients without endoscopical or histological abnormalities. Gastrin concentrations were also measured in extracts of antral biopsies. Basal plasma gastrin concentrations were not significantly different. In contrast, patients with the intestinal type of gastric cancer had a significantly lower plasma gastrin response to bombesin than did the normal subjects (P less than 0.01) and patients with the diffuse type of gastric cancer (P less than 0.05), but the result was not significantly different from that of the gastric ulcer patients. The antral gastrin content of the patients with the intestinal type of gastric cancer was significantly lower than in controls (P less than 0.005), the patients with the diffuse type of gastric cancer (P less than 0.05), and those with gastric ulcer (P less than 0.05). It is concluded that patients with the intestinal type of gastric cancer have, in contrast to those with the diffuse type of gastric cancer, an abnormally low plasma gastrin response to bombesin. This low response is due to a reduced gastrin content of the antral mucosa.

Aged↗

Effects of prolonged administration of metiamide on serum gastrin, gastrin content of the antrum and gastric corpus, and G-cell population in the rat.

The effect of prolonged metiamide administration on serum gastrin, gastrin content of the antrum and gastric corpus, and G-cell population was studied in the rat. A single subcutaneous injection of metiamide (200 mg/kg) at the onset of 16 days of continous treatment with three daily injections was followed by a fivefold increase in serum gastrin level at 4 hr in fasted and at 4 and 6 hr in fed rats. After 16 days of metiamide, the fed rats showed a peak in serum gastrin level of the same magnitude as on day 1, but only at 4 hr. Two hours later, the levels decreased rapidly to basal values. In the fasted animals, the response to metiamide was reduced to a threefold increase at 2 hr. There was no difference in gastrin content of the antrum and gastric corpus nor in volume density of the G-cells after the prolonged treatment compared with the controls. It is concluded that in spite of rises in serum gastrin, prolonged metiamide medication has no effect on the gastrin content of the antrum and gastric corpus nor on the G-cell population in the rat. Furthermore, after prolonged treatment, metiamide-induced gastrin release is diminished.

Animals↗

Role of cholecystokinin, gastrin and gastrin-releasing peptide in the regulation of pancreatic secretion in cats.

This study performed on 6 conscious cats with chronic pancreatic fistulas was designed to determine the role of cholecystokinin (CCK), gastrin and gastrin-releasing peptide (GRP) in stimulation of pancreatic secretion in this species. Pancreatic response to GRP infused intravenously in graded doses appears to be mediated predominantly by CCK because a CCK receptor antagonist, L-364,718, abolished this response. Also, gastrin appears to mediate in part the secretory response to GRP because blockade of gastrin receptors by L-365,260, given at the dose that completely abolished the pancreatic response to exogenous gastrin, caused a significant reduction in the bombesin-induced pancreatic secretion. CCK and partly gastrin appear to mediate the postprandial pancreatic secretion in cats as the administration of L-364,718 and L-365,260 inhibited this secretion by over 90 and 30%, respectively. In contrast, GRP does not seem to contribute to food-induced pancreatic secretory stimulation, because the blockade of GRP receptors using novel bombesin/GRP antagonist (RC-3100) failed to affect this secretion. We conclude that CCK and partly gastrin, but not GRP, play an essential role in the postprandial pancreatic secretion.

Amylases↗

Fasting and postprandial serum gastrin levels before and after highly selective gastric vagotomy, truncal vagotomy with pyloroplasty and truncal vagotomy with antrectomy: is there a cholinergic antral gastrin inhibitory and releasing mechanism?

Fasting serum gastrin levels and postprandial gastrin response were measured before and 1 month after highly selective vagotomy, truncal vagotomy with pyloroplasty and truncal vagotomy with antrectomy. The three groups of patients, 12 in each group, were closely matched for age, sex, maximum acid output and completeness of vagotomy. After highly selective and truncal vagotomy an identical and significant increase in fasting gastrin was observed, whereas after truncal vagotomy with antrectomy the pre- and postoperative fasting gastrin levels were not different. The net postprandial gastrin output over basal value was significantly increased after highly selective vagotomy, unchanged after truncal vagotomy and significantly lowered after truncal vagotomy with antrectomy. These results suggest the presence in the intact subject of a cholinergic inhibitory mechanism in the gastric body and fundus for the release of antral gastrin in the fasting and postprandial states and a possible cholinergic facilitatory mechanism for the release of antral gastrin after meals.

Clinical Trials as Topic↗

Growth of colorectal carcinoma cells: regulation in vitro by gastrin, pentagastrin and the gastrin-receptor antagonist proglumide.

The growth-regulating effects of pentagastrin, gastrin and the gastrin-receptor antagonist proglumide were investigated in three established cell lines derived from human colorectal carcinomas in vitro and after transplantation into nude mice. In vitro a significant increase of cell growth in the SW 403 cell line incubated with pentagastrin or gastrin was observed. In the Lovo cell line this effect was only detected after synchronization of cell growth. Pentagastrin and gastrin had no effect on the growth of the Ls 174 T cell line. Proglumide reduced cell proliferation in all three cell lines as well as in the L929S cell line derived from fibroblasts, which served as control. After transplantation into nude mice all tumor cell lines increased, Lovo and Ls 174 T as undifferentiated tumor, SW 403 as differentiated. Pentagastrin increased and proglumide decreased growth in SW 403 tumors, whereas no effect was observed on Ls 174 T and Lovo tumors. We therefore conclude that growth of some colorectal carcinomas is regulated by gastrin, but that the effect of proglumide is unspecific rather than related to blockage of gastrin receptors. The growth-regulating effect of gastrin could be due to tumor differentiation.

Animals↗

[The effect of antrectomy or total gastrectomy on calcium-induced gastrin secretion and gastrin release in man (author's transl)].

The effect of induced hypercalcemia on serum gastrin concentrations, measured by radioimmunoassay, and gastric acid secretion was studied in 20 healthy subjects, 8 patients after antrectomy and gastroduodenostomy (Billroth I), 12 patients after antrectomy and gastrojejunostomy (Billroth II) and in 9 patients after total gastrectomy and esophagojejunostomy. In normal man calcium stimulates gastric secretion and gastrin release. After antrectomy gastric secretion is still stimulated by calcium without changing serum gastrin levels. After total gastrectomy basal serum gastrin concentration is further reduced; calcium does not liberate gastrin. These results show that calcium-induced gastric secretion is caused by direct action at the parietal cell level besides the gastrin release from the antrum. In man, extra antral gastrin cannot be released by induced hypercalcemia.

Adult↗

Neural and paracrine regulation of gastrin release using rat antral mucosa in tissue culture--the effect of carbachol, bombesin, and anti-somatostatin antibody on gastrin release.

Gastrin release was significantly stimulated by the cholinergic agent carbachol at doses of 10(-4) M, 10(-5) M, and 10(-6) M. Peak stimulation was observed at 10(-5) M. Gastrin release was also significantly stimulated by bombesin at a dose of 10(-8) M, and 10(-6) M atropine which abolished the effect of carbachol in stimulating gastrin release had no effect on the bombesin-stimulated gastrin release. In addition, anti-somatostatin antiserum significantly stimulated gastrin release. These findings suggest that gastrin release is regulated by cholinergic and noncholinergic neurons the latter being thought to be a bombesin-containing neuron, and that antral somatostatin exerts a continuous restraint on gastrin release by the paracrine mechanism.

Animals↗

In vivo mitogenic effects of estradiol on colon cancers: role of gastrin and gastrin receptors.

We have previously reported mitogenic effects of gastrin on a mouse colon cancer (MC-26) cell line in vivo. The present studies were undertaken to determine if gonadal hormones can influence the mitogenic response of MC-26 cells to gastrin. The female gonadal hormone, estradiol (E2), was determined to be as mitogenic as pentagastrin (PG) for the growth of MC-26 tumors in mice; the mitogenic effects of E2 and PG were not additive. Female gonadal hormones were furthermore as effective as PG in maximally up-regulating gastrin receptor (GR) concentrations on MC-26 tumor membranes, which was confirmed in autoradiographic studies. Since PG and E2 had similar and non-additive trophic effects it was hypothesized that gastrin may be mediating the trophic effects of E2. Serum gastrin concentrations were significantly increased in E2 treated ovariectomized mice that correlated with an increase in tumor weights; E2 however was ineffective in stimulating the release of gastrin from perfused rat stomachs indicating that the increase in serum gastrin concentration on long-term treatment with E2 was mediated by some other mechanism. Saturable high-affinity E2 binding sites were not measured in MC-26 cells and tumors, supporting the possibility that mitogenic effects of E2 were probably mediated via indirect mechanisms. In summary our results indicate that both E2 and PG are equally mitogenic for colon cancer cells in vivo which may explain the sex- and age-related discrepancy in the incidence of human colon cancers.

Animals↗

Mutual relationships between chromogranins A and B and gastrin in individual gastrin cells.

The chromogranins A and B (CgA and CgB, respectively), originally detected in the adrenal medulla, are present in various endocrine organs. Remarkably, their immunoreactivities vary among different endocrine cell types and also within a given endocrine cell population. With densitometric techniques at the cellular level, individual gastrin cells (n = 318) from guinea pig antral mucosa were studied to measure their content of immunoreactive CgA, CgB, and gastrin. The composition of these secretory proteins in individual gastrin cells varied considerably but with predictable components. Statistical evaluation of the data showed that immunoreactivities for gastrin and CgA correlated negatively in these cells; CgA and CgB immunoreactivities also correlated inversely. On the other hand, immunoreactivities for gastrin and CgB exhibited a high positive correlation. The mutual relationships between gastrin, CgA, and CgB suggest that under physiological conditions biosynthetic pathways of these secretory constituents are linked to each other in individual gastrin cells.

Animals↗

Lessons from the gastrin and gastrin receptor knockout mice.

The gastric hormone gastrin was first recognized for its ability to induce acid secretion. Following the purification and subsequent development of specific radioimmunoassays for gastrin, it was also shown to be a regulator of oxyntic mucosal growth. To examine the importance of gastrin or its receptors during development in general and for gastric physiology specifically both have been knocked out. Gastrin and gastrin receptor knockout mice are viable, develop without any gross abnormalities, and are fertile. Even though gastrin acts as a growth factor during hypergastrinemia there was no general atrophy of the gastric mucosa in the knockout mice. However, the maturation of both parietal and ECL cells was disturbed and the number of parietal cells was reduced. Basal acid secretion was impaired and rendered the parietal cells unresponsive to secretagogues. Outside the stomach the mice had no apparent phenotype. However, studies have suggested that progastrin and glycine-extended proforms of gastrin may have biological importance, but these results are still circumstantial and identification of the implicated receptors will be crucial for further studies.

Animals↗

The effects of gastrin and gastrin analogues on pancreatic acinar cell membrane potential and resistance.

1 Intracellular recordings of membrane potentials and input resistance have been made from the exocrine acinar cells of mouse and rat pancreas placed in a tissue bath perfused with Krebs-Henseleit solution.2 The resting acinar cell membrane potential was about -38 mV. The acinar cells were stimulated by cholecystokinin-pancreozymin (CCK-PZ), gastrin and the gastrin-related polypeptides, caerulein and desulphated caerulein. The immediate effect of stimulation with these secretagogues was always a depolarization and a concomitant reduction in input resistance and time constant. Depolarization of the acinar cell membrane by these secretagogues was not abolished in the presence of atropine (1.4 muM).3 These peptide secretagogues were divided into the gastrin group and the CCK-PZ group according to the time course of the depolarizations and the shape of the dose-response curve. The depolarization evoked by the gastrin group returned quickly to the resting level but that evoked by the CCK-PZ group was long lasting. The time course and the dose-response curve for desulphated caerulein was identical with that of gastrin.4 It was confirmed electrophysiologically that the activity of gastrin is exerted by the C-terminal tetrapeptide; but the activity of caerulein depends on the C-terminal heptapeptide, especially the presence in the molecule of the sulphated tyrosyl residue at position 7 (numbering from the C-terminus). The equivalent sulphated tyrosyl residue in CCK-PZ is probably necessary for optimal activity of this polypeptide.5 The dose-response curves obtained by electrophysiological methods indicated that the relative potencies of the peptides on mouse pancreatic acinar cells were caerulein > CCK-PZ > gastrin. Synthetic human gastrin I was found to have a higher potency than either tetra- or pentagastrin.

Acetylcholine↗

Gastric clearance of gastrin during acid secretory responses to vagal activation and its effect on peripheral gastrin levels. A study on anesthetized cats.

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.

Animals↗