Effect of nephrectomy on the rate and pattern of the disappearance of exogenous gastrin in dogs

Severe Anemia from Multiple Gastric Hyperplastic Polyps in a Hemodialysis Patient after Long-term Use of a Proton-pump Inhibitor

A 90-year-old man on maintenance hemodialysis was admitted due to severe symptomatic anemia. Biopsies under esophagogastroduodenoscopy demonstrated that the cause of anemia was intermittent blood oozing from multiple gastric hyperplastic polyps. Even after successful eradication of Helicobacter pylori, he showed hypergastrinemia (480 pg/mL) owing to esomeprazole (proton-pump inhibitor) therapy for the past 4.5 years to treat reflux esophagitis. Seven months after we switched esomeprazole to famotidine (H2-receptor antagonist), those gastric polyps and anemia were remarkably ameliorated with lowered gastrin levels. This case indicates that long-term use of a proton-pump inhibitor triggers chronic hypergastrinemia, leading to gastric hyperplastic polyps and subsequent severe anemia.

Gastric acid secretion in experimental acute uremia

This study was conducted to evaluate gastric acid secretion in acute renal failure, highlighting the roles of renal mass and gastrin hormone. Acute uremic rats were divided into bilateral nephrectomized and bilateral ureteric obstruction groups. Gastric juice was collected for 2 h and analyzed for volume, free acidity, total acidity, and total acid output. Plasma levels of creatinine, urea, and gastrin were also determined. Bilateral nephrectomized and bilateral ureteric obstruction groups showed a significant increase in levels of free acidity, total acidity, and plasma gastrin. Compared with the ureteric obstruction group, nephrectomized rats showed a significant increase in gastric juice volume, total acid output, and plasma gastrin levels. Following pentagastrin stimulation, gastric juice volume, total acid output, free acidity, and total acidity were increased in the bilateral nephrectomy and ureteric obstruction groups compared with the respective control groups. The free and total acidity and total acid output also increased compared with the respective non-stimulated groups. Plasma creatinine and urea levels were significantly positively correlated with plasma gastrin, free acidity, and total acidity. Creatinine was positively correlated with total acid output, and gastrin was positively correlated with total acidity. In conclusion, acute renal failure promotes gastric acid hypersecretion that could potentially be attributed to high levels of gastrin hormone and uremic state per se.

Gastrin metabolism in neonatal pigs and grower-pigs

1. Half-life (1.7 +/- 0.1 min), distribution volume (146 +/- 12 ml/kg) and metabolic clearance rate (28 +/- 1 ml/kg/min) of little gastrin (G17) in neonatal pigs (N = 6; 3-12 days old) were significantly different from those in grower-pigs (N = 4; 161-170 days old) (2.4 +/- 0.1 min; 58 +/- 2 ml/kg; 7.9 +/- 0.3 ml/kg/min, respectively). 2. Half-life (33 +/- 4 min) and distribution volume (265 +/- 33 ml/kg) of big gastrin (G34) in neonatal pigs were greater but not significantly different from those in grower-pigs (24 +/- 2 min; 217 +/- 20 ml/kg, respectively). 3. Half-life of G17 in liver extracts from pigs 2-90 days old (40.4 +/- 4.2 min) was significantly longer than in kidney extracts (22.0 +/- 1.7 min). Half-lives of G34 in liver and kidney extracts from pigs 10-90 days old (78 +/- 6; 74 +/- 4 min, respectively) were significantly shorter than the corresponding values for 2-day-old pigs (134 +/- 3; 149 +/- 9 min, respectively). 4. Since G34 is the major circulating form of gastrin in neonatal pigs the relative longer half-life of G34 to G17 in these animals may contribute to the higher circulating gastrin concentration compared with that in older animals.

Serum gastrin in chronic renal failure: its relation to acid secretion, G-cell density, and upper gastrointestinal findings

The interrelations among fasting serum gastrin, serum creatinine, gastric acid secretion variables, and G-cell densities were analyzed in 47 patients with chronic renal failure (CRF). The patients also underwent gastroscopy and radiologic upper gastrointestinal barium examination. It is suggested that the hypergastrinemia seen in CRF is related to several factors: gastric acidity, grade of renal failure, G-cell density, and basal gastrin secretion rate. With regard to serum gastrin two different populations can be found, the cutting-off point being 300 ng/l. Although the group with high gastrin levels included significantly more patients with gastric body atrophy than the other group (4 of 11 versus of 1 of 36), most of them had no atrophy, which indicates that (an)other mechanism(s) is responsible for the hypergastrinemia. In the relation between serum gastrin and gastric acidity also, two differently behaving subgroups emerged. In the first, strong acidity change corresponded to minor gastrin change, whereas in the other, minor acidity change corresponded to marked gastrin change. The correlation coefficients between gastrin and acidity were high within both subgroups. During regular dialysis patients preserve the characteristics delineated from non-dialyzed values. Patients with signs of duodenal ulcer disease had high maximal acid output and low serum gastrin. Otherwise no associations were found between GI findings and the variables studied.

Effect of renal failure or portacaval shunt on release of neurotensin in man

Neurotensin-like immunoreactivity (NTLI) is released into the circulation following a meal. However, the factors influencing its degradation and metabolism are uncertain, but it is presumed that the kidneys and liver are involved. This study has determined the release of NTLI after a liquid fat meal (200 ml 20% Intralipid) in 10 healthy control subjects, five patients with stable chronic renal failure (CRF), and five patients after a portacaval shunt (PCS), to assess the possible role of the liver and kidney in NTLI metabolism. NTLI was measured by radioimmunoassay using both specific C and N terminally directed antisera. The results showed: Basal NTLI levels are similar in controls, after PCS, and in CRF. A liquid fat meal produces a single early peak of NTLI and levels are greater after PCS than in controls or CRF. Levels return much more slowly to basal in CRF and after PCS. Thus it is likely that both the liver and kidney are involved in the metabolism and clearance of NTLI.

The studies on the gastrin levels in the patients with renal failure

Fasting and postprandial gastrin levels were measured by radioimmunoassay in serum from 15 patients with renal failure and compared with those in 15 healthy controls. Pre- and posthemodialysis gastrin levels were also measured.

The fasting serum gastrin levels and serum gastrin response to a standard meal in the patients with renal failure were significantly higher than those in normal controls.

Fasting and meal stimulated gastrin levels were not significantly different in renal failure patients with peptic ulcer when compared with those in renal failure patients without peptic ulcer.

There were no statistically significant differences in the serum gastrin levels before and after hemodialysis in patients with renal failure.

Renal control of the peripheral uptake of exogenous gastrin in the dog

The extraction of plasma gastrin during intravenous infusion of exogenous hormone has been measured in the head, gastrointestinal tract, or kidney of dogs submitted to sham surgery, evisceration, or binephrectomy without or with subsequent kidney transplantation. A significant gastrin extraction was demonstrated not only in the kidney, but also in the head and in the gastrointestinal tract; moreover, plasma gastrin extraction in the head and the bowel was considerably reduced by binephrectomy and was brought back to control values after subsequent kidney transplantation. A non-specific effect of surgery and a variation in peripheral blood flow seem to be excluded. Thus a control by the kidney of the peripheral removal of blood gastrin is evidenced, the mechanism of which remains hypothetical.

Serum gastrin in patients with chronic renal failure

The realisation that circulating gastrin is heterogeneous necessitates a reappraisal of gastrin's role in the increased incidence of duodenal ulcer disease that occurs in chronic renal failure. Radioimmunoassays employing region-specific antisera have been used to examine renal and extrarenal factors controlling serum gastrin concentration in patients with chronic renal failure. The present study has shown that basal serum gastrin concentrations measured with a carboxyl-terminal specific antibody were significantly higher in eight patients with chronic renal failure treated by dietary restriction (388+/-196 pM) than in 14 patients with chronic renal failure treated by haemodialysis (28.7+/-4.6 pM). However, basal gastrin concentrations in both groups of patients were significantly higher than in 25 normal subjects (12.3+/-1.8 pM) and showed significant negative correlations with maximal gastric acid secretion (p < 0.01). Markedly raised basal gastrin concentrations were observed only in chronic renal failure patients who were also achlorhydric. Although the peak postprandial increment in big gastrin concentration in 11 chronic renal failure patients (34.0+/-7.5 pM) was significantly greater (p < 0.05) than in 25 normal subjects (19.5+/-4.6 pM), the little gastrin responses were not significantly different. In addition, clearance of exogenous little gastrin was similar in four chronic failure patients (clearance half time: 8.1+/-0.7 min) and four normal subjects (clearance half time: 6.5+/-1.2 min). These studies suggest that the human kidney is unimportant in the metabolism of little gastrin. As circulating little gastrin is six times more potent than big gastrin in stimulating acid secretion, these studies suggest that the raised gastrin concentrations observed in patients with chronic renal failure have little significance in terms of their increased incidence of duodenal ulcer disease.

Therapeutic effect of cimetidine in patients undergoing haemodialysis

Blood concentrations of cimetidine were measured and the therapeutic effect of the drug assessed patients undergoing maintenance haemodialysis. Thirteen patients were given a single oral 200-mg dose of cimetidine a mean of 2.7 hours before the start of dialysis. Dialysing for 6--12-6 m2 hours led to a mean fall of 71% in blood cimetidine concentration during haemodialysis. Nine patients with various upper gastrointestinal lesions diagnosed endoscopically were treated for up to six weeks with a reduced cimetidine dose of 200 mg 12-hourly; two patients received two courses of treatment. Repeat endoscopy after treatment disclosed satisfactory healing, and the drug did not accumulate. This lower dose regimen is recommended for patients receiving dialysis who develop upper gastrointestinal lesions for which a histamine H2-receptor antagonist is indicated.

Gastric function and histology in chronic renal failure

Gastric function and histology were investigated in 24 patients with untreated chronic renal failure. At endoscopy nine patients had oesophagitis, 12 patients were considered to have gastritis, and the duodenum appeared inflamed in 20 patients. Endoscopic biopsies were taken at standard sites in the stomach and duodenum; gastritis was found in all patients, and 17 patients had duodenitis. Stimulated acid secretion was impaired in seven out of 20 patients and acid hypersecretion was found in a further two patients. Pepsin output correlated well with acid output in these patients. Fasting serum gastrin levels were elevated in 12 of the 19 patients tested. Patients with atrophic gastritis had low acid outputs and hypergastrinaemia, and when extensive gastritis was present, the patients tended to have more severe renal failure and hyposecretion of acid. Three patients were studied again after regular haemodialysis or renal transplantation and were found to show marked endoscopic and histological improvement.

Serum level of immunoreactive gastrin: influence of kidney function

Serum gastrin levels have been studied in 70 patients with chronically reduced glomerular filtration rate (GFR) as estimated by 51Cr-EDTA clearance, creatinine, and beta2-microglobulin values. A strong dependence upon GFR was found, although the correlation between gastrin levels and GFR was not as high as that between beta2-microglobulin and GFR, indicating the existence of extrarenal factors regulating the levels of circulating gastrin. In a separate group of 31 patients on maintenance dialysis the mean gastrin level was 65.9 pmol/l--that is, a fourfold increase compared to healthy subjects. Three of the uraemic patients had pronounced rises in serum gastrin in the range 800-1800 pmol/l. Finally, the influence of acute alterations of kidney function on serum gastrin was studied in 11 patients undergoing renal transplantation. In addition to a GFR dependence the results indicate the existence of feedback mechanisms in gastrin homeostasis. Although the clinical importance of the increased gastrin levels in renal failure is unknown, hypergastrinaemia occurs with sufficient frequency to be involved in upper gastrointestinal complications of uraemic patients.

Disappearance half-time of endogenous and exogenous secretin in dogs

We have used a sensitive and specific radioimmunoassay to measurespectively. the disappearance half-times of exogenous porcine secretin and endogenous canine secretin in the dog and found them to be 2-45 and 2-85 minutes, respectively.

Gastric and duodenal ulcer and their associated diseases

Assessments of likely associations between ulcer and other diseases are hindered by the frequent lack of controls, by controls which are inadequate, and by inadequate descriptions of techniques used. The inherent biases in some of the techniques have also probably been insufficiently appreciated. Ulcer is common in the community and much of the evidence adduced to suggest ulcer/other-disease associations may well be describing oridinary ulcer frequency which has been underestimated. With such problems in mind, few of the proposed associations bear examination. Ulcer is probably unusually frequent in patients undergoing treatment for chronic renal failure. It is possibly more frequent in association with hyperparathyroidism and in cirrhotics, in cardiovascular disease (except hypertension), and in chronic respiratory disease. Evidence for other associations is not compelling.

Cholecystokinin metabolism in man and dogs

We have developed a sensitive, specific and reproducible radioimmunoassay for cholecystokinin (CCK) with which basal levels of CCK of between 400-800 pg/ml have been measured in normal man, in patients with diabetes and with duodenal ulcer disease, and in normal dogs. After a meal, circulating levels of CCK rose to 1000-1200 pg/ml in human subjects. Release of CCK was more rapid in diabetic and duodenal ulcer patients than in normal subjects, but elevated postprandial levels persisted much longer in normal subjects. Patients with the Zollinger-Ellison syndrome had elevated values of cholecystokinin which rose after a meal. Lack of correlation between elevated basal levels of gastrin and CCK in patients with the Zollinger-Ellison syndrome suggest that the hypercholecystokininemia may be absolute. The disappearance half-time of exogenous CCK was about 21/2 minutes in normal subjects as well as in diabetic and duodenal ulcer patients. Studies in dogs demonstrated no uptake of basal levels of cholecystokinin by the kidney; on infusion of exogenous CCK-33, the kidney extracted 43% of the total CCK presented and 56% of the integrated CCK. We conclude that: 1) circulating basal and postprandial levels of CCK may be measured in a reproducible fashion; 2) postprandial release of CCK is more rapid in diabetic and duodenal ulcer patients than in normal man; 3) the disappearance half-time of exogenous CCK in man and dogs is about 21/2 minutes; 4) the kidney is a major site for uptake of CCK.

Extraction of circulating endogenous gastrin by the gastric fundus

The effect of circulatory transit of the gastric fundus on serum levels of endogenous gastrin measured directly by radioimmunoassay has been studied in 14 dogs. Gastrin was measured in samples obtained simultaneously from the arterial inflow and venous outflow of the gastric fundus. During basal conditions, transit of the gastric fundus resulted in no change in gastrin concentration. During periods of stimulated gastrin release from the antrum, nine of the 14 dogs demonstrated a significant gastric acid secretory response. In these dogs there was a significant arteriovenous difference (approximately 30%) in circulating gastrin values. In the remaining five dogs, which did not demonstrate a significant gastric acid secretory response, there was no arteriovenous difference in circulating gastrin values. It is concluded that the gastric fundus is an important site for the inactivation of stimulated levels of circulating gastrin.