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PubMedDate not supplied

Importance of sulfation of gastrin or cholecystokinin (CCK) on affinity for gastrin and CCK receptors.

We investigated the importance of sulfation of gastrin or cholecystokinin (CCK) on influencing their affinity for gastrin or CCK receptors by comparing the abilities of sulfated gastrin-17 (gastrin-17-II), desulfated gastrin-17 (gastrin-17-I), CCK-8 and desulfated CCK-8 [des(SO3)CCK-8] to interact with CCK or gastrin receptors on guinea pig pancreatic acini. For inhibiting binding of 125I-gastrin to gastrin receptors, gastrin-17-II (Kd 0.08 nM) greater than CCK-8 (Kd 0.4 nM) greater than gastrin-17-I (Kd 1.5 nM) greater than des(SO3)CCK-8 (Kd 28 nM). For inhibiting binding of 125I-Bolton Hunter-labeled CCK-8 to CCK receptors the relative potencies were: CCK-8 much greater than des(SO3)CCK-8 = gastrin-17-II greater than gastrin-17-I. Each peptide interacted with both high and low affinity CCK binding sites. The relative abilities of each peptide to interact with high affinity CCK receptors showed a close correlation with their abilities to cause half-maximal stimulation of enzyme secretion. These results demonstrate that, in contrast to older studies, sulfation of both CCK and gastrin increase their affinities for both gastrin and CCK receptors. Moreover, the gastrin receptor is relatively insensitive to the position of the sulfate moiety, whereas the CCK receptor is extremely sensitive to both the presence and exact position of the sulfate moiety.

Amylases↗
PubMed1984

[Changes of gastrin levels in autoimmune thyroid disorders. Part I: Thyroid functions and gastrin levels].

The relationship between thyroid disorders and gastric pathophysiology has been studied mainly from standpoints of gastric histology and gastric acid output capacity. Though anti-gastric antibody has been thought to play a part in this relationship, there have been no clear conclusions obtained about that. Since blood gastrin levels are easily measurable by radioimmunoassay today, the relationship between thyroid disorders and gastric pathophysiology has drawn attention again from a standpoint of gastrin levels. Seino et al. have reported about hypergastrinemia in hyperthyroidism, speculating that beta-adrenergic hyperresponsiveness of gastrin-producing cells could be the mechanism of hypergastrinemia. However, there are other reports which mentioned feedback mechanism between gastrin and gastric acid or interaction of gastrointestinal hormones as the main mechanism of hypergastrinemia. In this study, the problem of gastrin in Graves' disease and chronic thyroiditis were studied by measurement of fasting serum gastrin levels and gastric juice excretion in view of feedback mechanism between gastrin-producing cells and parietal cells which are the target cells of gastrin. Following results were obtained. Fasting serum gastrin levels in Graves' disease were 236.2 +/- 39.1 (mean +/- SE) pg/ml for 39 hyperthyroid patients and 126.3 +/- 23.9 pg/ml for 35 euthyroid patients. These levels were significantly higher than those of sex and age-matched control subjects with P less than 0.001 and P less than 0.05, respectively. Fasting serum gastrin levels in serial studies of 13 patients with Graves' disease were 222.3 +/- 56.7 pg/ml before treatment and 167.3 +/- 56.6 pg/ml at the time of euthyroid state after a mean observation period of 6.6 +/- 1.1 months. Fasting serum gastrin levels at the time of euthyroid state decreased significantly when compared with fasting serum gastrin levels before treatment (P less than 0.05). Fasting serum gastrin levels in chronic thyroiditis were 160.7 +/- 51.1 pg/ml for 24 hypothyroid patients and 96.4 +/- 24.7 pg/ml for 31 euthyroid patients. Each of these levels had no significant differences when compared with sex and age-matched control subjects. Fasting serum gastrin levels in serial studies of 10 patients with chronic thyroiditis were 81.1 +/- 18.0 pg/ml at the time of hypothyroid state and 91.5 +/- 15.2 pg/ml at the time of euthyroid state after a mean observation period of 7.1 +/- 2.1 months. Fasting serum gastrin levels before treatment had no significant differences when compared with fasting serum gastrin levels in euthyroid state.(ABSTRACT TRUNCATED AT 400 WORDS)

Adolescent↗
PubMed1990

Relationship between gastrin cell number, serum, antral mucosa and luminal gastrin concentration and gastric acidity in antral atrophic gastritis.

The aim of our study was to investigate the relationship between gastrin producing cell density with antral mucosa, luminal and serum gastrin concentration in antral atrophic gastritis. Our study group consisted of 17 patients: six with mild atrophic gastritis, seven with moderate atrophic gastritis and four with severe atrophic gastritis. None of the patients had type-A atrophic gastritis but the body mucosa was affected by superficial gastritis at various extent in some. A group of 15 healthy subjects served as control. All subjects underwent gastroscopic examination with multiple bioptic sampling. Radioimmunoassay was used for gastrin determination and photomicroscopy for gastrin producing cell density assessment. Electron microscopy was used to assess the gastrin producing granule density index. Patients with moderate and severe atrophic gastritis showed a lower gastric acidity and acid output as compared to control. Serum gastrin did not show significant differences among the groups. In moderate and severe atrophic gastritis, gastrin producing cell granule density index, gastrin producing cell density and antral mucosa gastrin concentration were significantly lower when compared with control and decreased with advancing of the severity of atrophic gastritis. In atrophic gastritis, however, the latter two measurements were not correlated. In moderate and severe atrophic gastritis luminal gastrin concentration significantly increased, compared with control, after the severity of atrophic gastritis. Gastrin producing cell granule density index and luminal gastrin concentration showed a significant correlation with gastric pH. These data suggest that in antral atrophic gastritis with reduced gastric acidity, the decrement of gastrin producing cells is followed by gastrin producing cell hyperfunction with increased luminal release of gastrin.

Adult↗
PubMed1997

The effect of gastrin-releasing peptide on gastrin and somatostatin messenger RNAs in humans infected with Helicobacter pylori.

BACKGROUND & AIMS: Gastrin-releasing peptide stimulates gastrin secretion but also inhibits its release via somatostatin. Exogenous gastrin-releasing peptide stimulates a greater increase in plasma gastrin concentrations in patients infected with Helicobacter pylori than in uninfected controls. Because this infection suppressed gastric mucosal somatostatin, we studied whether the increased gastrin response was a result of an abnormal response of the somatostatin cell. METHODS: Patients without dyspeptic ulcers received an infusion of either gastrin-releasing peptide or saline on separate occasions. Acid secretion was measured, and gastric biopsy specimens were taken for gastrin and somatostatin messenger RNA (mRNA) analysis and H. pylori diagnosis. RESULTS: In response to gastrin-releasing peptide, the increase in plasma gastrin concentrations in the infected patients was significantly higher than in the uninfected. Antral gastrin mRNA also increased significantly in the infected group but decreased significantly in the uninfected group. Basal somatostatin was lower in the infected group; gastrin-releasing peptide produced a significant increase in antral somatostatin mRNA concentration in infected, but not uninfected, patients. CONCLUSIONS: The somatostatin cell responds to gastrin-releasing peptide in H. pylori infection. Gastrin-releasing peptide normally inhibits gastrin mRNA expression, but inhibition is deficient in H. pylori infection, possibly because of low stimulated somatostatin levels.

Adult↗
PubMed2001

Plasma levels of progastrin but not amidated gastrin or glycine extended gastrin are elevated in patients with colorectal carcinoma.

BACKGROUND: The relationship between plasma gastrin levels and colorectal cancer is controversial. When confounding factors which increase plasma gastrin levels are taken into account, it has been shown that gastrin levels are not elevated in patients with colorectal cancer. However, these studies only measured amidated gastrin. Total gastrin (which includes unprocessed, partially processed, and mature forms of gastrin) has been shown to be elevated in patients with colorectal cancer. AIMS: The aim of this study was to determine whether fasting plasma levels of progastrin, amidated gastrin, or glycine extended gastrin are elevated in patients with colorectal cancer or colorectal polyps compared with controls. METHODS: Progastrin, amidated gastrin, and glycine extended gastrin were estimated by radioimmunoassay using the following antibodies: L289, 109-21, and L2. Blood samples were analysed for Helicobacter pylori by an enzyme linked immunosorbent assay. RESULTS: Median progastrin levels were significantly higher in the cancer group (27.5 pmol/l) than in the polyp (< or =15 pmol/l) or control (< or =15 pmol/l) group (p=0.0001 There was no difference in median levels of amidated gastrin between groups. Median levels of amidated gastrin were significantly higher in H pylori positive patients (19 pmol/l) than in H pylori negative patients (8 pmol/l) (p=0.0022). Median plasma progastrin levels were significantly higher for moderately dysplastic polyps (38 pmol/l) compared with mildly dysplastic (15 pmol/l) and severely dysplastic (15 pmol/l) polyps (p=0.05). CONCLUSIONS: Plasma levels of progastrin, but not amidated gastrin or glycine extended gastrin, are significantly elevated in patients with colorectal cancer compared with those with colorectal polyps or controls, irrespective of their H pylori status. We conclude that measuring plasma progastrin levels in patients with colorectal cancer is warranted.

Adult↗
PubMed1991

Influence of gastrin, gastrin receptor blockers, epidermal growth factor, and difluoromethylornithine on the growth and the activity of ornithine decarboxylase of colonic carcinoma cells.

Polyamines are essential factors of cell growth and differentiation. Modulation of the cellular polyamine content by 2-difluoromethylornithine (DFMO) inhibiting ornithine decarboxylase (ODC), or by hormones inducing ODC, influences cell growth. Gastrin acts trophically on some colonic carcinomas and their growth is inhibited by gastrin receptor blockers. The mechanism of the trophic action of gastrin on colonic carcinomas is not known. In this study the effect of gastrin, gastrin receptor blockers, epidermal growth factor (EGF) and DFMO on growth and ODC activity of four human colon carcinoma cell lines (SW 403, SW 1116, LS 174 T and Lovo) was investigated. Growth and ODC activity of all cell lines were inhibited by DFMO. Growth of the SW 403 cell line was increased by gastrin and inhibited by the gastrin receptor blocker benzotrypte. The other cell lines did not respond to gastrin and the gastrin receptor blocker. In SW 403 cells ODC activity was increased by gastrin, and was also elevated after treatment with the gastrin receptor blocker. These in vitro results were confirmed by studies on tumours that developed from SW 403 cells in nude mice. Combination of benzotrypte and DFMO did not enhance the antiproliferative effect. EGF increased growth of SW 403 cells, but no induction of ODC activity was measured. LS 174 T cells were not stimulated by EGF. Medium replacement was the strongest stimulus of ODC activity in SW 403 cells already inducing ODC after 3 h. During cell culture ODC activity was high after seeding and decreased continuously with increasing cell density. These data suggest that gastrin induces ODC in gastrin-sensitive colonic carcinoma cells. DFMO appears to be a valuable antiproliferative agent in colonic carcinoma cells.

Animals↗
PubMed1994

Synthesis and characterization of a new labeled gastrin ligand, 125-I-BH-[Leu15]-gastrin-(5-17), on binding to canine fundic mucosal cells and Jurkat cells.

In the course of our study concerning gastrin and cholecystokinin (CCK) receptors, we have synthesized and characterized a new labeled gastrin ligand, 125I-BH-[Leu15]-gastrin-(5-17) [(3-[125I]iodo-4-hydroxyphenyl)-propionyl-[Leu15]-gastrin-(5-17)]. Binding of 125I-BH-[Leu15]-gastrin-(5-17) to isolated canine fundic mucosal cells was specific, saturable and of high affinity. 125I-BH-[Leu15]-gastrin- (5-17) and 125I-BH-CCK-8[(3-[125I]iodo-4-hydroxyphenyl)-propionyl-CCK-8] interact with isolated canine fundic mucosal cells with small differences in maximal binding capacities and affinities, 3800 +/- 900 binding sites/cell (Kd = 0.52 +/- 0.23 nM) and 6200 +/- 1100 binding sites/cell (Kd = 0.31 +/- 0.18 nM), respectively. The relative order of potencies for gastrin and CCK analogs in displacing 125I-BH-[Leu15]-gastrin-(5-17) binding correlated well with those obtained using 125I-BH-CCK-8. Selective CCK/gastrin antagonists L-364,718 (MK-329) and L-365,260 also inhibited 125I-BH-[Leu15]-gastrin-(5-17) binding. These results indicate that 125I-BH-[Leu15]-gastrin-(5-17) binds to gastrin receptors in isolated canine fundic mucosal cells. We have also characterized 125I-BH-[Leu15]-gastrin-(5-17) binding to the human Jurkat lymphoblastic cell line (Jurkat cells) known to express the CCK-B/gastrin receptor. Saturation experiments have shown that both 125I-BH-[Leu15]-gastrin-(5-17) and 125I-BH-CCK-8 interact with a single class of high-affinity binding sites in the Jurkat cell line.(ABSTRACT TRUNCATED AT 250 WORDS)

Amino Acid Sequence↗
PubMed2000

Gastrin and gastrin receptor activation: an early event in the adenoma-carcinoma sequence.

BACKGROUND AND AIMS: Gastrin and the cholecystokinin type B/gastrin receptor (CCKBR) have been shown to be expressed in colorectal adenocarcinoma. Both exogenous and autocrine gastrin have been demonstrated to stimulate growth of colorectal cancer but it is not known if gastrin affects the growth of colonic polyps. The purpose of this study was to determine if gastrin and CCKBR are expressed in human colonic polyps and to determine at which stage of progression this occurs. METHODS: A range of human colonic polyps was assessed for gastrin and CCKBR gene and protein expression. RESULTS: Normal colonic mucosa did not express gastrin or CCKBR. Gastrin and CCKBR reverse transcription-polymerase chain reaction products were detected and verified by specific hybridisation with an oligo probe on Southern blots. Gastrin and CCKBR were expressed in 78% and 81% of polyps, respectively. Both genes were coexpressed in 97% of cases. Immunohistochemistry identified progastrin in 91%, glycine extended gastrin 17 in 80%, and amidated gastrin 17 in only 47% of polyps. CCKBR was present in 96% of polyps. Expression of gastrin and CCKBR was seen in all histological types and sizes of polyps. CONCLUSIONS: This study is the first to show widespread expression of both gastrin and its receptor in colorectal polyps. Their activation occurs early in the adenoma-carcinoma sequence. Gastrin may promote progression through the adenoma-carcinoma sequence.

Adenoma↗
PubMed1986

Role of gastrin and gastrin receptors on the growth of a transplantable mouse colon carcinoma (MC-26) in BALB/c mice.

We recently reported trophic response of transplantable mouse colon cancer cells (MC-26) to pentagastrin, in vivo, and demonstrated gastrin receptors on MC-26 cells, in vitro. In the present study, growth of MC-26 cells in mice, in response to pentagastrin, was studied in relation to binding kinetics and capacity of gastrin receptor. Gastrin receptor levels on mouse fundic and colonic membranes and on MC-26 cellular membranes were determined before MC-26 cell inoculation and designated as Day 0 levels. Four groups of mice were next inoculated with MC-26 cells and given injections of either pentagastrin (treated) or normal saline (control) for 10 or 15 days. At the end of the treatment periods, body, tumor, fundic, and colon weights were noted and gastrin receptor measured. tumor and fundic weights increased significantly within 15 days of pentagastrin treatment, compared to control values. In control (non-pentagastrin treated) mice, the binding affinity of gastrin receptor on tumor membranes was significantly decreased and associated with the complete loss of high-affinity gastrin receptor (Kd = less than 0.5 nM) by Day 15 of tumor growth. On the other hand, both the binding affinity and gastrin receptor levels of tumor membranes were maintained at Day 0 values by pentagastrin treatment. Endogenous gastrin was therefore ineffective in maintaining high-affinity gastrin receptor on control tumors. A significant number of low-affinity gastrin-binding sites (Kd = less than 2 nM) appeared in control tumors by Day 15, which could reflect rapid dedifferentiation or conformational changes of gastrin receptor in the absence of high levels of normal regulatory hormones. These studies demonstrate that the trophic effects of gastrin on MC-26 cells are probably mediated by its regulation and maintenance of the binding affinity and capacity of gastrin receptor on the cancer cells, in vivo.

Animals↗
PubMed1983

Endogenous gastrin release and antral gastrin concentration in gastroesophageal reflux patients and normal subjects.

In this study we compared both endogenous gastrin release to a known gastrin stimulant, phenylalanine, and fasting antral mucosal gastrin concentration in normal subjects and patients with documented gastroesophageal reflux. Resting lower esophageal sphincter pressure in the reflux patients (14.7 +/- 1.5 mm Hg) was significantly less (p less than 0.01) than in the normal subjects (27.5 +/- 2.7 mm Hg). Basal serum gastrin concentrations were similar in the two groups. There were significant (p less than 0.05) increases in peak serum gastrin in response to intragastric administration of phenylalanine in both normal subjects (20.6 +/- 6.7 pg/ml, p less than 0.05) and refluxers (22.4 +/- 3.0 pg/ml, p less than 0.01) but there were no significant differences in these responses between normals and refluxers. Mean integrated gastrin response to phenylalanine in the reflux patients (812 +/- 116 pg ml-1 h-1) was slightly higher than that in normals (609 +/- 328 pg ml-1 h-1) although the difference was not significant. Antral gastrin concentration was slightly higher in reflux patients (15.7 +/- 2.2 ng/mg tissue) than in normals (10.4 +/- 4.2 ng/mg tissue), although this difference was not significant. There was no correlation between antral gastrin concentration and either integrated serum gastrin response or gastric acid output. We conclude that there is no difference between patients with gastroesophageal reflux and normal subjects with regard to serum gastrin levels, endogenous gastrin release, or antral gastrin concentration. These observations suggest no role for gastrin in the mediation of lower esophageal sphincter incompetence or the pathophysiology of gastroesophageal reflux.

Adult↗
PubMed1997

Time-dependent changes of serum gastrin and gastrin receptors in the rat oxyntic mucosa after proximal gastric vagotomy.

Proximal gastric vagotomy (PGV) is a first-choice approach for the surgical treatment of duodenal peptic ulcer. However, a high percentage of recidivism takes place after this surgical strategy. To study the possible involvement of gastrin in ulcer recidivism, serum gastrin levels and gastrin receptors in gastric mucosa were determined at several times after PGV in rats. Gastrin concentration was determined using a commercial radioimmunoassay kit and gastrin receptors were analyzed in oxyntic mucosa membrane preparations using 125I-labeled 15-Leu-gastrin-17 as label. Our results show a significant, time-dependent increase in serum gastrin concentration, reaching highest values at 12 weeks after PGV. Similarly, a significant increase in the number of gastrin receptors (Bmax) and in the dissociation constant (Kd) occurred from 1 to 12 weeks post-PGV. Since gastrin exerts a positive feedback effect on its receptors, the PGV-dependent increase in serum gastrin concentration explains the up-regulation of the gastrin receptors in the rat oxyntic mucosa. Furthermore, an increase in the number of gastrin receptors after vagotomy may be at least partially responsible for the recidivism in duodenal peptic ulcers after this surgical approach.

Animals↗
PubMed1976

Current problems in the measurement of gastrin release. A reproducible measure of physiological gastrin release.

The interpretation of gastrin release is confused because of variation in the technique of the radioimmuoassay of gastrin, the lack of a standard stimulus for the release of gastrin and diversity in the method used to express the results. These problems have been analysed (a) by examining the cross-reactivity of three gastrin antisera and using each of the antisera to measure basal gastrin levels in fasting normal subjects, duodenal ulcer and post-vagotomy patients; (b) by determining a satisfactory stimulus for gastrin release in normal subjects; (c) by examining the results to determine the best method of presenting the data. The different a ntisera used were found to give different levels of plasma gastrin in the same sample of plasma. This was not related to the cross reactivity of the antisera. An English breakfast was found to be the most satisfactory stimulus for the release of gastrin. The expression of the results of such a stimulus of gastrin release was affected least by assay variation when the incremental integrated gastrin response was used. It is concluded that the incremental integrated gastrin response to an English breakfast is a satisfactory method for exploring variations in gastrin release.

Adult↗
PubMed1976

Is gastrin a major determinant of basal lower esophageal sphincter pressure? A double-blind controlled study using high titer gastrin antiserum.

Studies were performed in anesthetized opossums to determine the influence of binding of circulating gastrin with a high titer gastrin antiserum on lower esophageal sphincter pressure. Gastrin antiserum or control antiserum was administered intravenously in successive doses of 0.02, 0.1, and 0.5 ml/kg on separate days. The lower esophageal sphincter pressures were measured for 1 h before and for 1 h after antiserum administration. The control serum caused no binding of opossum circulating gastrin, nor did it modify lower esophageal sphincter pressure. On the other hand, the administration of gastrin antiserum resulted in the binding of 85-90% of circulating gastrin, but it did not reduce sphincter pressure. A continuous infusion of 0.25 mug-kg-1-h-1 of synthetic human gastrin I caused a significant (P less than 0.05) increase in the sphincter pressure, a 30-fold increase in gastric acid output, and a fourfold increase in immunoreactive gastrin in the opossum blood. Prior treatment with 0.1 ml/kg of gastrin antiserum antagonized and 0.2 ml/kg of the antiserum abolished the gastrin-stimulated gastric acid secretion and the stimulating effect of gastrin on lower esophageal sphincter pressure. However, neither dose of antiserum modified basal lower esophageal sphincter pressure. It is concluded that circulating gastrin may be an important determinant of basal sphincter pressure.

Animals↗
PubMed1986

Identification of a gastrin binding protein in porcine gastric mucosal membranes by covalent cross-linking with iodinated gastrin.

A gastrin binding protein (GBP) has been identified in detergent extracts of porcine gastric mucosal membranes by covalent cross-linking to 125I-[Nle15]gastrin with disuccinimidyl suberate. The apparent molecular weight of the cross-linked complex (80,000) is uneffected by reduction suggesting that the GBP is not composed of disulfide-bonded subunits. Subtraction of the molecular weight of 125I-gastrin indicates that the molecular weight of the GBP is 78,000. A similar molecular weight has been observed previously for the gastrin receptor (74,000) on intact canine parietal cells and plasma membranes therefrom, and for the receptor for the related hormone cholecystokinin (76,000-85,000) on pancreatic acinar membranes under reducing conditions. The similarity in molecular weight between the gastrin receptor and the solubilized GBP suggests that the latter protein is probably the gastrin receptor. However, the concentration (2 microM) of [Nle15]gastrin required for 50% inhibition of cross-linking of gastrin to the GBP solubilized in 0.1% Triton X-100 is 200-fold greater than the value (10 nM) observed for the gastrin receptor on isolated canine gastric parietal cells. A lower concentration (0.3 microM) of [Nle15]gastrin was required to inhibit cross-linking in a milder detergent (0.4% digitonin, 0.08% cholate). Thus, the reduced affinity for gastrin of the putative solubilized form of the gastrin receptor appears to be a result of detergent extraction.

Animals↗
PubMed1987

Beta-adrenergic stimulation of gastrin release mediated by gastrin-releasing peptide in rat antral mucosa.

The present studies were directed to examine the effects of beta-adrenergic and cholinergic stimulation on gastrin release and to assess the potential role of gastrin-releasing peptide in exerting these effects, utilizing incubated rat antral mucosa. Rat antral mucosa was incubated at 37 degrees C in Krebs-Henseleit bicarbonate buffer, pH 7.4, continuously gassed with 95% O2-5% CO2. After 1 h media were sampled for radioimmunoassay measurement of gastrin content. Inclusion of carbachol (2.5 X 10(-6) M) in culture medium increased medium gastrin concentration by 106 +/- 28% (P less than 0.01); addition of specific antibodies to gastrin-releasing peptide to the culture medium did not affect carbachol-stimulated gastrin release. Inclusion of isoproterenol (10(-9) M) in culture medium did not affect somatostatin release into the medium, but increased medium gastrin by 234 +/- 24% (P less than 0.001). However, in contrast to carbachol, addition of antibodies to gastrin-releasing peptide to culture medium decreased isoproterenol-stimulated gastrin release by 67 +/- 9% (P less than 0.001). Results of these studies indicate that, under the conditions of these experiments, beta-adrenergic, but not muscarinic, stimulation of gastrin release may be mediated, at least in part, through gastrin-releasing peptide.

Animals↗
PubMed1987

Origin of gastrin liberated by gastrin releasing peptide in man.

Gastrin release induced by gastrin releasing peptide (GRP) in man has been studied in patients before and after complete resection of the antrum and duodenal bulb, as well as after pancreaticoduodenectomy according to Whipple. Studies in healthy subjects showed that 400 pmol/kg an hour of GRP induced a maximal release of gastrin. Infusion of this dose of GRP after a complete resection of the antrum and duodenal bulb induced a small, but significant increase in gastrin concentrations. After pancreaticoduodenectomy, however, GRP infusion had no effect on serum gastrin concentrations. In patients previously subjected to an incomplete antrectomy, GRP infusion was followed by a gastrin response considerably higher than after a complete antrectomy. Our results would suggest that GRP is capable of releasing gastrin predominantly from the antrum and the duodenal bulb, but also a small amount of gastrin from the remaining part of the duodenum. Gastrin releasing peptide infusion and determination of gastrin release may be of clinical significance in showing remaining significant gastrin pools in patients with recurrent ulceration after previous gastric resections.

Adult↗
PubMed1989

Studies of the release of gastrin from the human duodenum induced by gastrin-releasing peptide.

In the present study the influence of duodenal exclusion and vagotomy on basal release of gastrin from extra-antral stores has been investigated in addition to the consequences of these procedures on the gastrin response to gastrin-releasing peptide (GRP) infusion. Basal gastrin concentrations and the response to GRP were measured in seven patients after a Whipple operation, in seven patients after antrectomy combined with selective gastric vagotomy and B I reconstruction, in seven patients operated on with antrectomy, selective gastric vagotomy, and Roux-en-Y reconstruction, and finally in seven patients after antrectomy, truncal vagotomy, and Roux-en-Y reconstruction. Gastrin was measured by a highly specific radioimmunoassay. Very low concentrations were obtained after a Whipple operation, and no increase followed GRP infusion. The basal gastrin concentrations were slightly higher in antrectomized patients, irrespective of whether a selective gastric vagotomy had been added. However, in these patients a significant gastrin response followed GRP infusion. Duodenal exclusion seemed not to influence the response to GRP. On the other hand, extragastric vagotomy was followed by low gastrin concentrations in the basal state and only a marginal response to GRP administration. These results strongly suggest that GRP releases gastrin from the human duodenal mucosa and that duodenal exclusion does not alter the response of the duodenal gastrin cells to GRP stimulation. Vagal denervation of the duodenal mucosa seems to suppress the gastrin response to GRP, indicating an excitatory influence of the vagus nerve.

Adult↗
PubMed1988

Effect of aging on gastric acid secretion, serum gastrin, and antral gastrin content in rats.

The purpose of this study was to characterize the effects of aging on gastric acid secretion and on serum and antral concentrations of gastrin in rats. Young and old Fischer 344 rats were prepared with gastric fistulas. Twenty-four hours after surgery, graded doses of human synthetic gastrin-17 (SHG-17) (2, 5, 10, 20, and 40 micrograms/kg) were given intravenously in random order. Gastric secretions were collected for gastric acid measurement before and at 15-min intervals after each dose of gastrin. In a separate study, blood was collected and the stomachs were removed for antral gastrin extraction from fed young and old rats. Serum and antral gastrin was measured by radioimmunoassay. The basal and gastrin-stimulated acid secretions were significantly decreased in aged rats compared to the young rats. The basal acid output was 0.4 +/- 0.2 microeq/15 min in the aged rats and 1.5 +/- 0.5 microeq/15 min in the young. The maximal acid output stimulated by gastrin was 11.1 +/- 1.8 microeq/15 min in the aged rats and 24.2 +/- 2.8 microeq/15 min in the young. Both serum and antral concentrations of gastrin were significantly decreased in aged rats. Serum gastrin concentration was 114.8 +/- 7.4 pg/ml in the aged rats and 192.0 +/- 14.4 pg/ml in the young. Antral gastrin concentration was 3.9 +/- 0.5 micrograms/g tissue in the aged rats, which was significantly less than the concentration in the young (6.5 +/- 0.4 micrograms/g tissue). Antral gastrin content did not change with aging.(ABSTRACT TRUNCATED AT 250 WORDS)

Aging↗