Laparotomy and proximal gastric vagotomy in Zollinger-Ellison syndrome: results of a 16-year prospective study.

OBJECTIVE: Pharmacological control of gastric acid hypersecretion in the Zollinger-Ellison syndrome has steadily improved, but medical treatment does not address the underlying tumor. The objective of this study was to evaluate the long-term effectiveness of a surgical approach to both tumor and acid hypersecretion in 22 patients with the Zollinger-Ellison syndrome. METHODS: Patients underwent laparotomy to resect tumors, combined with vagotomy to reduce acid secretion, followed by postoperative antisecretory therapy, if necessary. RESULTS: No surgical mortality or serious morbidity occurred. Tumor was found at laparotomy in nine patients (41%) and during long-term follow-up in an additional two patients (9%). Ten-year survival is 81%, with a long-term cure rate of at least 14%. Most patients (86%) have had long-term inhibition of acid secretion. Eight patients have discontinued regular use of acid-inhibiting medications. Patients requiring medication need less of it, and they have an improved acid inhibitory response to medication for up to 16 yr after surgery. CONCLUSION: Cure of the Zollinger-Ellison syndrome is possible in a minority of patients. Acid secretion can be safely reduced in almost all patients with laparotomy/vagotomy, usually allowing discontinuation, or reduced dose, of acid-inhibiting drugs. Long-term survival and quality of life are generally excellent.

Effects of aging and gastritis on gastric acid and pepsin secretion in humans: a prospective study.

BACKGROUND & AIMS: Recent studies suggesting that gastric secretion does not decrease with aging included few elderly individuals and measured only acid secretion. The aims of this study were to measure gastric acid and pepsin output in 206 health Americans (age range, 18-98 years) and to compare secretion rates with gastric histology. METHODS: Immediately after basal and pentagastrin-stimulated acid and pepsin outputs were measured, oxyntic biopsy samples were obtained. RESULTS: Gastric acid and pepsin output rates were similar in young (age range, 18-34 years) and middle-aged (age range, 35-64 years) groups. Stimulated acid output was reduced approximately 30% in the elderly (age range, 65-98 years). However, after adjustment for histology, Helicobacter pylori infection, and other variables, age had no independent effect on acid output. The decline in acid secretion in the elderly was primarily related to a higher prevalence of chronic atrophic gastritis and a lower prevalence of smoking. Pepsin output was reduced by approximately 40% in the elderly. After adjustment for other variables, age remained a robust predictor of reduced pepsin output. CONCLUSION: Although advancing age has no independent effect on gastric acid secretion, it is associated with reduced pepsin output independent of atrophic gastritis, H. pylori infection, and smoking.

Review article: drug-induced pancreatitis.

Drugs are a relatively uncommon cause of pancreatitis in adult patients, but should be considered when other reasonable causes of pancreatitis are not present. A wide variety of drugs have been reported to cause pancreatitis. Drug-induced pancreatitis is almost always acute and may be mild to fatal in severity. Definite proof that a drug causes pancreatitis requires that pancreatitis develops during treatment with the drug, that other likely causes of pancreatitis are not present, that pancreatitis resolves upon discontinuing the drug, and that pancreatitis usually recurs upon readministration of the drug. For ethical reasons, rechallenge with the suspect drug can be done only if the drug is necessary to treat a serious condition; thus this highly convincing piece of evidence relating the drug to pancreatitis may not be available. Information about drug-related pancreatitis is often not readily available, particularly for newer drugs. Clinicians should consider obtaining information directly from regulatory agencies and manufacturers as well as the literature.

Prostaglandin E2 desensitizes cAMP-mediated pepsinogen secretion in chief cells.

To evaluate whether pretreatment with prostaglandin E2 (PGE2) could desensitize pepsinogen secretion in chief cells from guinea pig, chief cells were pretreated with 10 microM PGE2 for up to 30 min. Desensitization of subsequent PGE2-stimulated secretion was maximal after 15 min, averaging only 29 +/- 9% (SE) of pepsinogen secretion in control cells stimulated with 10 microM PGE2. Desensitization was half-maximal with 30 nM PGE2. PGE2 pretreatment at 4 degrees C did not cause desensitization. In cells pretreated with 10 microM PGE2 for 15 min and then given 60 min to recover, responsiveness increased to 79 +/- 7% of that for control cells stimulated with PGE2. Thus the desensitization was reversible. Pretreatment with PGD2 and PGF2a did not alter subsequent PGE2-mediated secretion. PGE2-induced desensitization was heterologous but mediator specific because pepsinogen secretion was reduced in response to adenosine 3',5'-cyclic monophosphate (cAMP)-mediated agents (secretin and vasoactive intestinal peptide) but not Ca(2+)-mediated agents (CCK-8, gastrin, or carbachol). Pretreating chief cells with 10 microM PGE2 did not significantly alter cAMP generation in response to PGE2, secretin, or 3-isobutyl-1-methylxanthine, suggesting that desensitization was not mediated by an alteration in the receptor-coupled adenylate cyclase system. Because PGE2 pretreatment also desensitized pepsinogen secretion induced by the synthetic cAMP analogues 8-BrcAMP and 2'-O-monobutyryl-8-BrcAMP, it is likely that the ability of PGE2 to desensitize pepsinogen secretion in chief cells isolated from guinea pig is due to a mechanism distal to generation of cAMP.

Gastric acid and pepsin hypersecretion in conscious rabbits.

In conscious, gastric fistula rabbits, gastric acid and pepsin secretion averaged 4.5 +/- 0.1 mmol/h (1.3 mmol.kg-1.h-1) and 4.9 +/- 0.3 IU/h (1.6 IU.kg-1.h-1), respectively; these values represent approximately 40-50% of maximal output. Basal serum gastrin concentrations averaged 24 +/- 4 pg/ml and did not correlate with basal acid secretion. Atropine and vagotomy incompletely inhibited basal acid secretion (by 84 and 50%, respectively) and completely inhibited 2-deoxy-D-glucose-stimulated gastric acid secretion. Atropine and vagotomy similarly inhibited basal pepsin secretion by 50 and 40%, respectively. Ranitidine decreased acid and pepsin secretion, but as with atropine, inhibition was not complete (73 and 37%, respectively). Although omeprazole did not affect pepsin secretion, omeprazole completely inhibited basal acid secretion and elevated postprandial intragastric pH above 5.0. Conscious, gastric fistula rabbits have the highest basal acid and pepsin output among species commonly studied. Both vagal-cholinergic pathways and histamine drive basal acid and pepsin secretion in the rabbit.

Gastrin-releasing peptide directly releases pepsinogen from guinea pig chief cells.

Gastrin-releasing peptide (GRP) and bombesin can stimulate pepsinogen release by both gastrin-dependent and -independent mechanisms. Using isolated guinea pig gastric chief cells, we determined that GRP can act directly on the guinea pig chief cell to cause pepsinogen release. GRP and bombesin stimulated a 2.5- to 3-fold increase in pepsinogen release above basal release. Substance P also stimulated a small but significant increase in pepsinogen release. No gastrin immunoreactivity was detected in the supernatants of cells stimulated with up to 1 microM GRP or bombesin or 1 mM carbachol. GRP-stimulated pepsinogen release was completely inhibited by GRP/bombesin receptor agonists as well as substance P receptor antagonist but not by antagonists to receptors for gastrin, the octapeptide of cholecystokinin (CCK-8), secretin, vasoactive intestinal peptide (VIP), or muscarinic agents. Substance P-stimulated pepsinogen release was completely inhibited by substance P receptor antagonist but not by GRP/bombesin receptor antagonists. An additive effect on pepsinogen release was seen when GRP was combined with maximally effective concentrations of adenosine 3',5'-cyclic monophosphate (cAMP)-mediated agents (VIP, secretin, 8-BrcAMP) but not with calcium-mediated agents (carbachol, CCK-8, gastrin). These results indicate that GRP can directly stimulate pepsinogen release from guinea pig chief cells by a specific GRP receptor that mobilizes intracellular calcium.

Gastric acid secretion, gastrin release, and gastric emptying in humans as affected by liquid meal temperature.

We investigated the effect of the temperature of a liquid meal on intragastric temperature, gastric acid secretion, gastrin release, and gastric emptying in normal human subjects. Coffee (360 mL) was infused into the stomach through a nasogastric tube at 58 (steaming hot), 37, or 4 degrees C (ice cold). Intragastric temperature, measured by an intragastric temperature sensor attached to the nasogastric tube, returned to body temperature 16.7 +/- 2.7 min after the hot meal and 23.8 +/- 1.1 min after the cold meal. Gastric acid secretion increased after hot, warm, and cold coffee but the initial temperature of the meal had no effect on gastric acid secretion. The temperature of the meal also had no effect on serum gastrin concentrations, which increased significantly after all the meals. Gastric emptying of hot, warm, or cold coffee meals was similar. These findings indicate that over a wide temperature range, the temperature of a liquid meal has little effect on gastric function in humans.

Soy protein meals stimulate less gastric acid secretion and gastrin release than beef meals.

Soy protein is a widely used, inexpensive, and nutritious source of dietary protein. In contrast to beef protein, the effects of soy protein on gastric acid secretion and serum gastrin concentration have not been evaluated. We compared the effects of meals containing the same amounts of either isolated soy or beef protein on acid secretion and serum gastrin concentration in normal humans. Acid secretion measured by in vivo intragastric titration was 30%-40% less with soy than beef protein (p less than 0.05), whether isolated soy protein alone was compared with a mixed beef meal containing carbohydrate and fat or whether soy or beef meals containing similar amounts of fat were compared. Average gastrin rises were 65%-75% less with soy than with beef (p less than 0.01). The explanation for less gastrin release with soy than with beef is unclear, but lower serum gastrin concentrations with soy probably accounted for reduced acid secretion. These results indicate that the source of dietary protein in a meal may be an important determinant of gastric acid secretion and gastrointestinal hormone release.

Cimetidine pharmacokinetics in patients with Zollinger-Ellison syndrome.

Although most patients with Zollinger-Ellison syndrome can be effectively treated with histamine H2-receptor antagonists, many patients require large doses of drug to inhibit gastric acid secretion adequately. The purpose of the present study was to compare the pharmacokinetics of a 1200-mg oral dose of cimetidine in 9 patients with Zollinger-Ellison syndrome requiring more than 2.4 g/day of cimetidine with 5 age-matched normal volunteers receiving intravenous pentagastrin infusions. Poor responsiveness to cimetidine in patients with Zollinger-Ellison syndrome has several different causes. The concentration of cimetidine in the blood required to inhibit gastric acid secretion by 50% was markedly increased in 3 of the patients with Zollinger-Ellison syndrome, suggesting parietal cell resistance. One patient showed a substantial decrease in cimetidine absorption and 4 patients had delayed cimetidine absorption. Thus 7 of the 9 patients with Zollinger-Ellison syndrome who required more than 2.4 g/day of cimetidine to inhibit gastric acid secretion had abnormal cimetidine pharmacokinetics.

Characterization of receptors for VIP on pancreatic acinar cell plasma membranes using covalent cross-linking.

Vasoactive intestinal peptide (VIP) receptors on guinea pig pancreatic acini differ from those on all other tissues in containing a high-affinity VIP receptor and a low-affinity VIP receptor that has a high affinity for secretin. To characterize the molecular components of these receptors, 125I-VIP was covalently cross-linked to these receptors by four different cross-linking agents: disuccinimidyl suberate, ethylene glycol bis (succinimidyl succinate), dithiobis (succinimidylpropionate), and m-maleimidobenzoyl N-hydroxysuccinimide ester. Analysis by sodium dodecyl sulfate-polyacrylamide gel electrophoresis demonstrated a single major polypeptide band of Mr 45,000 and a minor polypeptide band of Mr 30,000 were cross-linked to 125I-VIP. Covalent cross-linking only occurred when a cross-linking agent was added, was inhibited by GTP, was inhibited by VIP receptor agonists or antagonists that interact with VIP receptors, and not by other pancreatic secretagogues that interact with different receptors. For inhibiting both cross-linking and binding of 125I-VIP to the major polypeptide Mr 45,000 and the minor polypeptide Mr 30,000 components, the relative potencies were VIP greater than helodermin greater than rat growth hormone releasing factor greater than peptide histidine isoleucine greater than secretin. The apparent molecular weight of the cross-linked polypeptides were unchanged by dithiothreitol. Thus the high-affinity VIP receptor on pancreatic acinar cell membranes consists of a single major polypeptide of Mr 45,000, and this polypeptide is not a subunit of a larger disulfide-linked structure. Furthermore, either the low-affinity VIP/secretin-preferring receptor was not covalently cross-linked under the experimental conditions or it consists of a major polypeptide with the same molecular weight as the high-affinity VIP receptor.

Treatment of acid-peptic diseases by inhibition of gastric H+,K+-ATPase.

The substituted benzimidazoles are a new class of drugs with a unique antisecretory action. These agents have great potential for treatment of acid-peptic disease because they produce substantial, long-lasting inhibition of gastric acid secretion by inhibiting gastric H+,K+-ATPase in the gastric parietal cell. Clinical trials of omeprazole, a substituted benzimidazole, indicate that it is safe and effective for short-term treatment of patients with duodenal or gastric ulcer, and it is highly effective for long-term treatment of patients with Zollinger-Ellison syndrome.

Famotidine, a new, potent, long-acting histamine H2-receptor antagonist: comparison with cimetidine and ranitidine in the treatment of Zollinger-Ellison syndrome.

Famotidine, a new, potent, long-acting histamine H2-receptor antagonist was compared with cimetidine and ranitidine in 9 patients with Zollinger-Ellison syndrome. The mean minimum daily requirement of famotidine to control gastric acid hypersecretion was 0.24 g (range 0.08-0.48 g) compared with 2.1 g (range 0.6-3.6 g) for ranitidine and 7.8 g (range 1.2-13.2 g) for cimetidine. Equally potent doses of the three drugs had similar onsets of action, but the duration of action of famotidine was 30% longer than the duration of action of either ranitidine or cimetidine (p less than 0.05). Eight patients were treated for up to 9 mo (mean 6 mo) with good control of gastric acid hypersecretion and with no evidence of biochemical or hematologic toxicity. These studies demonstrate that famotidine is nine times more potent than ranitidine and 32 times more potent than cimetidine, has a longer duration of action than ranitidine or cimetidine, and is both safe and effective in the long-term therapy of Zollinger-Ellison syndrome.

Omeprazole: effective, convenient therapy for Zollinger-Ellison syndrome.

The acute and long-term effects of omeprazole on gastric acid secretion were examined in 11 patients with Zollinger-Ellison syndrome. Basal gastric acid secretion was inhibited by 50% 3 h after a single 60-mg dose of omeprazole and 78% 4 h after administration of omeprazole. Patients were treated with a single daily dose of omeprazole, and the dose requirement was defined as the lowest dose of omeprazole that would reduce gastric acid secretion to less than 10 mEq/h during the last hour before the next dose. The mean daily dose requirement was 70 mg (range 20-160 mg). Ten of the 11 patients were given omeprazole once a day and 1 patient required omeprazole every 12 h. When omeprazole was discontinued after several months of therapy, mean basal gastric acid secretion was inhibited by greater than 50% 48 h after administration of omeprazole. Omeprazole continued to inhibit gastric acid secretion during 1-9 mo of therapy and patients remained free of toxicity or side effects related to omeprazole. Omeprazole is a highly effective inhibitor of gastric acid secretion in patients with Zollinger-Ellison syndrome. Because of its potency and long duration of action, omeprazole offers an advance in convenient medical therapy for Zollinger-Ellison syndrome compared with the histamine H2-receptor antagonists.

Comparison of the effectiveness of ranitidine and cimetidine in inhibiting acid secretion in patients with gastric hypersecretory states.

The H2-histamine receptor antagonists ranitidine and cimetidine were compared for their abilities to control gastric acid hypersecretion on a short- and long-term basis in 22 patients with gastric acid hypersecretory states. Nineteen patients had Zollinger-Ellison syndrome, one patient had systemic mastocytosis, and two patients had idiopathic hypersecretion. The rates of onset of the action of cimetidine and ranitidine were the same. The actions of both drugs were increased by anticholinergic agents, and there was a close correlation between the daily maintenance dose of each drug needed to control acid secretion. However, ranitidine was threefold more potent than cimetidine both in acute inhibition studies and in the median maintenance dose needed (1.2 g per day for ranitidine and 3.6 g per day for cimetidine). Sixty percent of the males developed breast changes or impotence while taking cimetidine and in all cases these changes disappeared when cimetidine was replaced by ranitidine. Treatment with high doses of cimetidine (one to 60 months; median, 11 months) or ranitidine (two to 31 months; median, 14 months) was not associated with hepatic or hematologic toxicity or alterations of serum gastrin concentrations, but ranitidine therapy was associated with a significantly lower serum creatinine level than seen with cimetidine therapy. The results show that both drugs can adequately inhibit acid secretion in patients with gastric hypersecretory states. Both are safe at high doses, but ranitidine is threefold more potent and does not cause the antiandrogen side effects frequently seen with high doses of cimetidine.

Comparison of ranitidine and cimetidine in the treatment of gastric hypersecretion.

The H2-histamine receptor antagonists, cimetidine and ranitidine, were compared for their abilities to control acid secretion on a short- and long-term basis in 13 patients with gastric hypersecretory disorders. The rate of onset of action did not differ between the two drugs. The actions of both drugs were increased by an anticholinergic agent, and there was a close correlation between the daily maintenance dose of each drug needed to control acid secretion. However, ranitidine was threefold more potent than cimetidine and no male patient developed breast changes or impotence while taking ranitidine. Treatment with high doses of ranitidine for 6 to 25 months was not associated with hepatic or hematologic toxicity or alterations of serum gastrin levels, but was associated with a significantly lower serum creatinine level than that seen with cimetidine therapy. These studies show that ranitidine can adequately inhibit acid secretion in patients with gastric hypersecretory disorders, is safe at high doses, does not cause the antiandrogen side effects frequently seen with high doses of cimetidine, and is threefold more potent than cimetidine. Patients who are relatively resistant to cimetidine will have proportional resistance to ranitidine.

The actions of tetraethylammonium on dispersed acini from guinea pig pancreas.

In dispersed acini from guinea pig pancreas, replacing extracellular sodium by tetraethylammonium (1) abolished carbamylcholine-stimulated amylase secretion but did not alter the increase in amylase secretion caused by the C-terminal octapeptide of cholecystokinin, bombesin, ionophore A23187, vasoactive intestinal peptide or 8-bromoadenosine 3':5' monophosphate, (2) caused a parallel rightward shift in the dose-response curve for carbamylcholine-stimulated amylase secretion and (3) inhibited binding of N-[3H]methyl scopolamine to muscarinic cholinergic receptors. Detectable inhibition of carbamylcholine-stimulated amylase secretion and binding of N-[3H]methyl scopolamine occurred with 300 microM tetraethylammonium, and half-maximal inhibition of these functions occurred with 1-2 mM tetraethylammonium. Replacing extracellular sodium by Tris did not alter the stimulation of enzyme secretion caused by any secretagogue tested. These results indicate that the tetraethylammonium is a muscarinic cholinergic receptor antagonist and that enzyme secretion from pancreatic acini does not depend on extracellular sodium.

Intravenous infusion of L-isomers of phenylalanine and tryptophan stimulate gastric acid secretion at physiologic plasma concentrations in normal subjects and after parietal cell vagotomy.

To determine whether intravenous infusion of individual amino acids stimulated gastric acid secretion in man, graded doses of phenylalanine, tryptophan, glycine, alanine, histidine, and NaCl control were infused on separate days in nine healthy subjects. Intravenous infusion of phenylalanine and tryptophan significantly stimulated gastric acid secretion to 50 and 52%, respectively, of the acid secretory response to intragastric peptone. Intravenous alanine and histidine were without effect, whereas glycine produced a slight response. Serum gastrin concentrations did not significantly change during intravenous amino acid infusion, except in response to 0.1 M phenylalanine. However, the increase in serum gastrin occurred 2 h after acid secretion had significantly increased in response to the 0.025 M phenylalanine infusion. Plasma amino acid concentrations were measured during intravenous amino acid infusion and in response to a steak meal in five of the subjects. At a time when acid secretion was significantly increased during intravenous infusion of phenylalanine and tryptophan, plasma amino acids were similar to, or less than, that observed after the steak meal, suggesting that circulating levels of these three amino acids have a physiologic effect on gastric secretion in man. Intravenous infusion of a combination of graded doses of phenylalanine plus a continuous infusion of 0.01 M tryptophan shifted the dose-response curve to the left and resulted in a significantly greater response than to either amino acid alone. In five subjects with parietal cell vagotomy, intravenous phenylalanine and tryptophan stimulated acid secretion, whereas histidine was without effect, similar to normal subjects. These studies indicate that intravenous infusion of small amounts of phenylalanine (0.025 M, 3.1 mmol/h) and tryptophan (0.01 M, 1.25 mmol/h) stimulated gastric acid secretion at plasma concentrations similar to those observed after a steak meal, suggesting a physiologic role for circulating levels of these amino acids on gastric acid secretion. Because acid secretion increased at a time when serum gastrin was unchanged and since there was no correlation between changes in serum gastrin and acid secretion, the responses to phenylalanine and tryptophan are probably mediated by a nongastrin-related mechanism(s). Since both phenylalanine and tryptophan stimulated secretion in vagotomized subjects, the response is vagally independent. These observations suggest that circulating levels of these two amino acids have either a direct or indirect effect on or near the human parietal cell.

Clonidine and lidamidine to inhibit watery diarrhea in a patient with lung cancer.

A patient with watery diarrhea syndrome secondary to bronchogenic carcinoma responded to treatment with clonidine and lidamidine. Stool weight decreased to 43% and 53% of control on two separate trials of clonidine. Stool weight decreased to 35% of control during a trial of lidamidine. Both clonidine and lidamidine increased sodium and chloride absorption in vitro in human intestine. Clonidine, lidamidine, or drugs that are structurally similar may become therapeutic choices for secretory diarrhea.