[Hormonal changes and secretion and stomach mucosal microstructure in the course of H. pylori in patients with duodenal ulcer]

We designed this study to follow exocrine, endocrine and microstructural changes in duodenal ulcer patients with H. pylori infection in the course and after quadruple eradication regimen. Quadruple therapy appeared to be highly effective method of both ulcer healing and H. pylori eradication. We observed enhanced regeneration of gastric mucosa in the course of treatment. Almost immediate decrease of plasma gastrin and increase of plasma somatostatin and EGF concentration in gastric juice were noticed.

[Endocrine and exocrine gastric mucosal secretion in the course of H. pylori eradication in patients with non-ulcer dyspepsia]

Microstructural, endo- and exocrine changes in gastric mucosa of Non-Ulcer Dyspepsia patients with H. pylori infection in the course of eradication has been studied. Before, during and after anti H. pylori therapy plasma gastrin and somatostatin levels, EGF and somatostatin concentration in gastric juice and basal and pentagastrin stimulated gastric acid secretion were measured. Moreover microstructure of gastric mucosa specimens has been studied. Maximal Acid Output initially higher in NUD patients than in healthy volunteers increased slightly in the course of eradication. Plasma gastrin decreased while EGF and somatostatin concentration in gastric juice increased. After treatment the ratio of patients with pronounced features (activity) of gastritis was significantly reduced.

Gastric mucosal expression and luminal release of growth factors in gastric carcinoma and duodenal ulcer patients before and after eradication of Helicobacter pylori

Epidemiological studies have consistently shown an association between infection of Helicobacter pylori (Hp) and duodenal ulcer (DU) and gastric cancer. The mechanism of the ulcerogenic effect of Hp has been related to excessive gastrin release, gastric acid hypersecretion and gastric metaplasia in duodenum. The implication of Hp in gastric carcinogenesis has not been explained. In this study, mucosal expression of EGF and TGF alpha and luminal release of EGF as well as basal and pentagastrin-stimulated acid secretion and plasma gastrin levels have been determined in healthy subjects, gastric carcinoma and DU patients. It was found that Hp positive DU patients show excessive gastrin release and gastric acid secretion combined with increased expression and luminal release of EGF and TGF alpha. These changes returned to normal values two years after the eradication of Hp. Gastric cancer patients also showed increased expression of EGF and TGF alpha and highly increased plasma gastrin but their gastric acid secretion was markedly reduced possibly due to atrophy of oxyntic mucosa. This study indicates that overexpression of growth factors in gastric mucosa may be implicated in the pathogenesis of both duodenal ulcer and gastric cancer and that Hp positive hypochlorhydric and hypergastrinemic patients may be predisposed to development of gastric cancer.

New approach to 13C-urea breath test: capsule-based modification with low-dose of 13C-urea in the diagnosis of Helicobacter pylori infection

This study was designed to evaluate a novel modification of the non-invasive capsule-based 13C-urea breath test (13C-UBT). 114 patients were tested for Helicobacter pylori (HP) infection with the use of only 38 mg 13C-urea administrated in solid capsulated form. Obtained results were compared with tissue based methods: histology and rapid urease test (CLOtest). Results of histology and/or CLOtest were considered as the gold standard for each patient. In addition, also capsule-based, micro-dose (37kBq) 14C-urea breath test (14C-UBT) was performed. With a cut-off for delta-over-base values of 5/1000 (i.e., 5 per mil), 13C-UBT results (measured by non-dispersive infrared spectroscopy, NDIRS) correlated highly significant with combined results for invasive methods i.e., CLOtest + histology score. Compared with histology, CLOtest, and the gold standard, the diagnostic values of the test were: sensitivity 97%, specificity 95%, with positive and negative predictive values about 90% and 98% respectively. The modified 13C-UBT test was found to be in full concordance with 14C-UBT; there was 100% agreement in the diagnostic classification of all positive (89) and negative (25) patients. Described modification of 13C-UBT showed that presented modification of 13C-UBT is an excellent, simple, low cost, non invasive, and safe diagnostic tool in HP detection and should be recommended particularly in cases when the use of radioactive urea is contraindicated.

Oral cavity as permanent reservoir of Helicobacter pylori and potential source of reinfection

Recent studies in developed countries showed that neither dental plaques nor dentures are important reservoir for Helicobacter pylori (Hp), whereas studies in developing countries revealed a high prevalence of Hp in dental plaques, though elsewhere the culture of bacterium or its DNA analysis by polymerase chain reaction in the material obtained from oral cavity were not successful. This study was designed to compare the incidence of Hp in oral cavity (saliva, dental plaques and gingival pockets) using Campylobacter-like organism (CLO) test and culture and in the presence of Hp in the stomach using 14C-urea breath test (UBT), CLO-test and culture (antral biopsy specimens). Hundred dyspeptic subjects with endoscopically normal gastro-duodenal mucosa and 55 symptomatic patients with active duodenal peptic ulcer (DU) were tested for the presence of Hp. Thirty of these DU patients were also examined for presence of Hp in oral cavity and the stomach just before the start and 4 weeks after the termination of one week triple therapy (Omeprazole 20 mg bd, Clarithromycin 500 mg bd and Tinidazole 500 mg bd) when the DU was found endoscopically healed. In the group of 100 dyspeptic subjects, the Hp was detected by CLO-test in saliva, dental plaques and gingival pockets in 84%, 100% and 100% of cases and by the culture in 55%, 88% and 100%, respectively. The presence of Hp, as determined by UBT in the stomach in these subjects was 60%. Using CLO-test and culture, all (100%) out of 55 DU patients, were found to be Hp positive in the oral cavity and in 95% in the stomach. Following one week triple therapy in 30 DU patients, the Hp was still detected in oral cavity by CLO-test in all patients (100%) and by culture in 27 patients (90%), whereas in the stomach, the Hp was found by UTB and culture only in one of these patients (97% Hp eradicated). We conclude that the Polish population including dyspeptic and DU patients, the mouth is permanent reservoir of Hp and that the successful Hp eradication from the stomach by systemic therapy fails the Hp status in the oral cavity that might be a potential source of gastric reinfection in these patients.

Microdose 14C-urea breath test in detection of Helicobacter pylori

Etiologic role for Helicobacter pylori (Hp) seems to be well established in gastric pathology. The high urease activity of Hp can be used to detect this bacterium by non-invasive urea breath tests (UBT). We validated the microdose version of the test in which 37 kBq 14C-urea is given orally in capsule. With the cut off value > 100 DPM as positive, UBT results correlated highly significant with combined results for invasive methods i.e. CLOtest + histology score. The reproducibility of the test was 100%. The results obtained for the breath test performed locally were almost identical with that read at remote laboratory. The data found for fasting and fed states of subjects agreed in 87%. When 14C-urea was confined in the mouth of both Hp positive and Hp negative patients UBT showed the presence of urease activity in the mouth cavity. 14C-urea capsule based breath test is highly reliable, safe, and reproducible for detection of Hp in the stomach. Results can be obtained within 15 min if a scintilation counter is nearby, or breath samples can be mailed to a testing laboratory for analysis.

One week treatment with omeprazole, clarithromycin and tinidazole or lansoprazole, amoxicillin and metronidazole for cure of Helicobacter pylori infection in duodenal ulcer patients

We defined optimal Helicobacter pylori (Hp) treatment as Hp eradication rate about 90%, well-tolerated with few side-effects. Two centers carried out randomized trials including 90 patients (74% men, 26% women, ages ranging from 18 to 65, mean age 42 +/- 8) with active duodenal ulcers (DU). Patients were treated with the combination of Omeprazole (O) 20 mg bd + Clarithromycin (C) 250 mg bd + Tinidazole (T) (500 mg bd) or with Lansoprazole (L) 15 mg bd + Amoxicillin (A) 750 mg bd + Metronidazole (M) 500 mg bd administered for one week. The DU healing rate was evaluated by endoscopy and the Hp status by rapid urease CLO-test and 14C-urea breath test (UBT). The healing rate of the DU in a group treated with the combination of O + C + T was 91% and in group treated with L + A + M was 93%. The eradication of Hp in group O + C + T and L + A + M averaged 91% and 87%, respectively. There was no statistically significant difference in the DU healing rate and the Hp eradication rate between these two groups. Both treatments were accompanied by a marked rise in the basal and postprandial plasma gastrin levels and the rise in the intragastric pH but these alterations returned to the pre-treatment values 4 weeks after the termination of the therapy. Both treatments were well tolerated and the only side effect was the taste disturbance observed in few patents treated with O + C + T. None of patients discontinued the treatment because of the adverse events. We conclude that one week treatment using O + C + T or L + A + M are highly and equally effective in the healing of DU and in the eradication of Hp.

Helicobacter pylori infection after gastrectomy and vagotomy in duodenal ulcer patients

The eradication of Helicobacter pylori (Hp) is known to reduce the recurrence rate of duodenal ulcer (DU) to similar extent as gastrectomy but it is not clear what is the prevalence of Hp in DU patients after surgical interventions such as gastrectomy or vagotomy. The purpose of this study was to evaluate the influence of gastrectomy or truncal vagotomy with pyloroplasty on the prevalence of Hp in 51 DU patients just before and 6-8 months after these procedures. Using C14-urea breath test (UTB), rapid CLO-test and histology of the biopsy samples of gastric mucosa obtained during gastroscopy, the Hp was detected in all DU subjects submitted to operation. Following distal gastric resection (antrectomy) with Billroth II anastomosis (N = 32) due to an ulcer resistance to conservative therapy, peptic ulceration was not observed during 6-8 months in any of the examined subjects and the Hp was only rarely observed (only in 3 out of 32 operated patients). Histologically, in antral biopsies taken prior to surgery, all DU patients presented chronic active gastritis. After the surgery, the absence of Hp was confirmed also by histology. Histological evaluation of gastrectomy stump biopsies revealed typical chronic gastritis with concomitant foveolar hyperplasia and focal gland dilation. Following selective vagotomy and pyloroplasty (N = 19), the scarring of duodenal bulb (without active ulcer) was seen in 4 out of 19 operated patients but the Hp was detected in all (100%) cases. Gastric biopsies prior and after vagotomy revealed chronic active gastritis associated with Hp infection. Basal plasma gastrin was reduced after gastrectomy by about 30% and basal and maximal pentagastrin-induced acid secretion was decreased by about 60% and 70%, respectively. Vagotomy did not reduce activity of the mucosal inflammation and the incidence of Hp. Basal plasma gastrin level was increased by about 60%, while basal and pentagastrin induced acid secretion was decreased by 25% and 40%, respectively. Because of the high ulcer recurrence rate after vagotomy as opposed to low recurrence after gastrectomy, it is reasonable to conclude that (1) the disappearance of Hp and reduction in plasma gastrin and gastric acid secretion were probably the major factors responsible for the high efficacy of gastrectomy in prevention of ulcer recurrence, (2) in non-complicated DU, gastric surgery should be avoided and replaced by conservative anti-Hp therapy involving both antisecretory or bismuth agents and antimicrobial drugs which should provide similar therapeutic effects as surgery and (3) vagotomy should be eliminated as the method of treatment of DU because of the high recurrence of peptic ulceration and the failure of this procedure to affect the Hp status.

Eradication of Helicobacter pylori and gastrin-somatostatin link in duodenal ulcer patients

Helicobacter pylori (Hp) infection may be associated with duodenal ulcer (DU) and accompanied by increased release of gastrin and deficiency of somatostatin (S-S) but the mechanisms of these changes in DU patients after eradication of Hp have been little studied. Cholecystokinin (CCK) has been implicated in the feedback control of gastric acid secretion in healthy subjects but its contribution to secretory disorders in DU patients has been little examined. This study, therefore, investigated whether CCK participates in the impairment of postprandial gastrin release and gastric acid secretion in active DU patients. Tests were undertaken in 10 DU patients without or with elimination of the action of endogenous CCK using loxiglumide (LOX), a selective CCK-A receptor antagonist, before and 4 wk. after eradication of Hp with triple therapy (omeprazole, amoxycillin and bismuth). In Hp positive DU patients, the postprandial acid secretion (measured by continuous intragastric pH monitoring) was accompanied by a pronounced increment in plasma gastrin with negligible increase of intraluminal release of S-S. The administration of LOX in these patients did not affect significantly the postprandial pH profile and the rise in plasma gastrin. After eradication of Hp the median postprandial intragastric pH increased to about 4.3 (compared to 3.5 before the Hp eradication); the postprandial gastrin concentration was reduced by about 40%, while luminal release of S-S was increased 2 folds. The administration of LOX resulted in significantly greater decrease in median pH (3.1) and higher rise in postprandial plasma gastrin in these patients. Also the postprandial plasma S-S showed a small, but significant decline (by about 25%) as compared to that in placebo treated patients. This study provides evidence that: (1) Hp infection in DU patients is accompanied by enhanced gastrin release and the reduction in luminal release of S-S; (2) The failure of LOX to affect gastric secretion and plasma gastrin DU Hp infected patients could be attributed, at least in part, to the failure of endogenous CCK to control gastric acid secretion via release of S-S; (3) Hp infected patients appear to exhibit a deficiency of S-S release that can be reversed by the eradication of Hp indicating that both peptides may contribute to the acceleration of the ulcer healing following Hp eradication in DU patients; (4) The test with LOX and gastric luminal S-S assay may be useful in identification of Hp positive DU patients with CCK-mediated impaired feedback control of gastric secretion and deficiency of S-S caused by Hp infection.

Role of endogenous nitric oxide in the control of exocrine and endocrine pancreatic secretion

L-Arginine (L-Arg), that is a substrate for nitric oxide (NO) synthase, stimulates the release of pancreatic islet hormones but the mechanism of this stimulation is unknown. The aim of this study was to determine the role of NO in the control of endocrine and exocrine pancreatic secretion in response to sham feeding (SF), ordinary meat feeding (F), duodenal perfusion with nutrients and i.v. infusion of gastrin releasing peptide (GRP) or urecholine in conscious dogs with chronic pancreatic fistulas. SF1 F, duodenal nutrient and GRP and urecholine resulted in the stimulation of pancreatic secretion reaching, respectively, 50%, 50%, 40%, 85% and 20% of maximal response to caerulein (200 pmol/kg-h i.v.). Infusion of L-Arg (50 mg/kg + 5 mg/kg-h i.v.) almost doubled the basal pancreatic protein secretion and significantly increased the secretory response to SF, F, and duodenal nutrient. After i.v. administration of L-NNA (2.5 mg/kg + 0.5 mg/kg-h), an inhibitor of NO synthase, the pancreatic secretory responses to SF, F, duodenal nutrient, GRP and urecholine were significantly inhibited by about 74%, 70%, 70%, 80% and 30%, respectively. When L-Arg was combined with L-NNA, the reduction in pancreatic secretion induced by L-NNA was significantly attenuated. SF resulted in a marked rise in plasma insulin and glucagon and this response was completely abolished by L-NNA infusion. Insulin and glucagon levels were 2-3 folds increased by F and L-NNA infusion inhibited these responses while the addition of L-Arg partly reversed this inhibition. Duodenal nutrient produced several fold increase in plasma insulin and glucagon levels that were significantly reduced by L-NNA and this reduction was partially reversed by L-Arg. GRP also caused moderate rise in plasma insulin and glucagon levels which were significantly reduced by L-NNA and this was partially restored by L-Arg. We conclude that SF, F, duodenal nutrient, GRP or urecholine stimulate both the exocrine and endocrine pancreatic secretion and that these effects are mediated, at least in part, through the NO pathway.

Solcoseryl in prevention of stress-induced gastric lesions and healing of chronic ulcers

Solcoseryl, a deproteinized extract of calf blood, protects the gastric mucosa against various topical irritants and enhances the healing of chronic gastric ulcerations but the mechanisms of these effects have been little studied. This study was designed to elucidate the active principle in Solcoseryl and to determine the role of prostaglandins (PG) and polyamines in the antiulcer properties of this agent. Using both, the radioimmunoassay and radioreceptor assay, EGF-like material was detected in Solcoseryl preparation. Solcoseryl given s.c. prevented the formation of stress-induced gastric lesions and this was accompanied by an increase in the generation of PGE2 in the gastric mucosa. Similar effects were obtained with EGF. Pretreatment with indomethacin, to suppress mucosal generation of prostaglandins (PG), greatly augmented stress-induced gastric ulcerations and antagonized the protection exerted by both Solcoseryl and EGF. Solcoseryl, like EGF, enhanced the healing of chronic gastro-duodenal ulcerations. This effect was abolished by the pretreatment with difluoromethylornithine, an inhibitor of ornithine decarboxylase, the key enzyme in the biosynthesis of polyamines. The healing effects of Solcoseryl and EGF was also reduced by prednisolone which decreased the angiogenesis in the granulation tissue in the ulcer area. These results indicate that Solcoseryl 1. contains EGF-like material, 2. displays the protective and ulcer healing effects similar to those of EGF and involving both PG and polyamines and 3. acts via similar mechanism as does EGF.

Comparison of organ uptake and disappearance half-time of human epidermal growth factor and insulin

Epidermal growth factor (EGF), which was originally identified in salivary glands and saliva, has been also found in the kidney and urine, suggesting that the kidney may be an alternate source of this peptide. Liver was considered as the major site of the degradation of EGF but the involvement of other organs has been little studied. Therefore, we carried out comparative studies on the organ uptake and the disappearance half-time of EGF and insulin (having similar molecular size) in the same model of anesthetized dog with arterial (from aorta) and venous (from mesenteric, portal, hepatic, renal, femoral and jugular veins) blood sampling from various organs. Basal plasma level of EGF (1.32 +/- 0.33 pmol/l) and insulin (62.1 +/- 13.8 pmol/l) in the aorta was not significantly different from that recorded at various sampling sites. During i.v. infusion of EGF at 41.6 and 166.6 pmol/kg/h, the respective arterial EGF concentrations averaged 103 +/- 21 and 240 +/- 49 pmol/kg/h and the percent reduction in plasma EGF after passage through the head, leg, intestines and liver was about 30-50% and that after passage through the kidney was about 95%. During insulin (6.9 pmol/kg/h) infusion, the arterial hormone level averaged 227 +/- 21 pmol/l and this level was significantly reduced (by 23-42%) after passage through the head, leg, intestine, liver and kidney but no significant difference was found between various venous sampling sites. EGF and insulin appearing in the urine during EGF or insulin infusion accounted for about 40 and 7% of the difference between the entering and leaving renal masses of the peptide. Mean disappearance half time on stopping of EGF and insulin infusion was, respectively, 2.32 +/- 0.58 and 6.88 +/- 1.25 min. We conclude that unlike insulin, which is removed to similar extent by various organs including the kidney and the liver, EGF is taken up mainly by kidney and EGF present in urine originates mainly from renal clearance of peptide.

Gastric acid, gastrin and pancreatic polypeptide responses to modified sham feeding in duodenal ulcer patients before and after highly selective or truncal vagotomy

Gastric acid secretion, as well as gastrin and pancreatic peptide release into the bloodstream before and after TV or HSV were observed in 28 patients following modified sham feeding (MSF) and pentagastrin tests. Prior to surgery the majority of patients showed stimulation of gastric acid secretion and hormone release into the bloodstream as the result of the employed tests. The MSF-induced acid output (SAO) and pentagastrin-induced acid output (PAOpg) values were mainly observed immediately following the stimulus. In the majority of patients MSF triggered an increase in blood gastrin and PP concentrations. Nevertheless, the peak concentration values for the two hormones occurred at different time intervals following the stimulus. For gastrin the peak values appeared later than SAO, whereas for PP they occurred either in the course of or immediately after MSF. Irrespectively of, the type of surgical procedure used and the completeness of vagotomy, the values of BAO, PAO, SAO and PAOpg were significantly lower following the procedure. Blood hormone concentration, however, showed greater variations. The test stimulated gastrin release showed the peak values were greater after, than prior to, the surgery, whereas PP release was markedly inhibited. No correlation was found between gastric acid secretion, blood serum gastrin and PP levels.

Effects of an antral mucosectomy, L-364,718 and atropine on cephalic phase of gastric and pancreatic secretion in dogs

The purpose of this study was to determine the role of gastrin and cholecystokinin in the cephalic phase of gastrin release and gastric and pancreatic secretion in conscious dogs. Sham feeding in intact dogs increased gastric acid output to about 65% of histamine maximum and pancreatic protein to 23% of caerulein maximum. Significant increases in plasma gastrin and pancreatic polypeptide but not cholecystokinin occurred. Similar effects were obtained using insulin hypoglycemia or 2-deoxy-D-glucose glucocytopemia. Atropine eliminated gastric acid response to sham feeding, insulin, or 2-deoxy-D-glucose, significantly reduced the pancreatic protein response by about 60%, and abolished plasma pancreatic polypeptide but not plasma gastrin. Blocking of cholecystokinin receptors by L-364,715 did not affect gastric or pancreatic secretory responses to sham feeding, insulin, or 2-deoxy-D-glucose and failed to influence the accompanying increments in plasma gastrin and pancreatic polypeptide. In antral-mucosectomized dogs, sham feeding-induced acid output reached only 17% of histamine maximum but the increase in pancreatic protein output was similar to that in intact dogs. In these animals, background stimulation with G17I (62 pmol/kg per h) potentiated the gastric acid response to sham feeding but had little effect on pancreatic protein output. This study provides evidence that unlike gastric acid, the pancreatic protein response to physiological or pharmacological cephalic stimulation does not depend on vagally released gastrin but probably on direct vagal stimulation of the pancreas.

CCK receptors in release of pancreatic polypeptide (PP) in dogs

Pancreatic polypeptide (PP) is released after ingestion of protein-fat meals and following administration of some gut hormones (CCK and bombesin), but the hormonal contribution to the physiological release of PP has not been elucidated. We used specific and potent CCK-receptor antagonist, L-364,718, administered intravenously in a dose of 0.5 mumol/kg or intraduodenally in a dose of 2 mumol/kg to assess the role of CCK in the release of PP. Exogenous CCK-8 infused intravenously in gradually increasing doses (12.5-400 pmol/kg/hr) caused a dose-dependent increase in plasma PP from basal 28 +/- 4 pM to 136 +/- 18 pM, and this PP increase was completely suppressed by both intravenous and intraduodenal administration of L-364,718. Meat feeding caused a dramatic increase in plasma PP from a basal level of 26 +/- 4 pM to a peak of about 190 +/- 32 pM, and the pretreatment with intravenous or intraduodenal L-364,718 reduced this PP increase by about 60%. Duodenal perfusion with oleate (0.12-4.0 mmol/hr) or L-Trp (0.12-4.0 mmol/hr) also increased plasma PP, reaching, respectively, 180 +/- 28 pM and 76 +/- 6 pM. Pretreatment with intravenous or intraduodenal L-364,718 completely abolished the plasma PP responses to oleate and L-Trp. Bombesin (100 pmol/kg/hr) raised plasma PP to the level similar to that achieved by meat feeding and L-364,718 given intravenously or intraduodenally blocked completely these plasma PP increments.(ABSTRACT TRUNCATED AT 250 WORDS)

Immunoneutralization of circulating pancreatic polypeptide and pancreatic secretion

To determine the role of endogenous pancreatic polypeptide (PP) as a physiological inhibitor of pancreatic secretion, normal rabbit serum (control) or rabbit PP-antiserum was administered intravenously to dogs with chronic esophageal, gastric, and pancreatic fistulas. In all dogs tested, sham-feeding and ordinary feed with a meat meal resulted in a marked rise in the plasma level of immunoreactive PP that coincided with an increase in the exocrine pancreatic secretion of HCO3- and protein. After intravenous administration of PP antiserum, endogenous plasma PP was almost completely bound by infused antibodies to PP, whereas no such binding was detected after infusion of normal rabbit serum. In contrast, plasma gastrin remained unchanged both under basal and stimulated conditions. Immunoneutralization of PP, released endogenously, failed significantly to affect gastric acid and pancreatic protein responses to sham-feeding and the pancreatic HCO3- and protein responses to feeding a meat meal in chronic pancreatic fistula dogs. However, the PP antiserum abolished, in part, the inhibitory effect of exogenous PP on pancreatic secretion stimulated by exogenous hormones. We conclude that endogenous PP is not a physiological inhibitor of exocrine pancreatic secretion, as has been suggested previously.

Gastric acid and pancreatic polypeptide responses to modified sham feeding. Effects of truncal and parietal cell vagotomy

The effects of truncal vagotomy and parietal cell vagotomy on gastric acid secretion and plasma gastrin and pancreatic polypeptide release were studied in 28 duodenal ulcer patients under basal conditions and after modified sham feeding and infusion of pentagastrin (2 micrograms/kg/h). Before vagotomy gastric acid output in response to modified sham feeding was significantly higher than basal acid secretion in all subjects tested and reached about 45% of the pentagastrin maximum. No difference in the increase in acid response, or in the pancreatic polypeptide response to modified sham feeding was found between patients with high and low basal secretion. Plasma gastrin concentration was unaltered by modified sham feeding before and after truncal vagotomy or parietal cell vagotomy, although after vagotomy it tended to reach higher values than before this procedure. After truncal vagotomy, basal pancreatic polypeptide concentration was decreased and modified sham feeding-induced pancreatic polypeptide increment was completely eliminated. Four weeks after parietal cell vagotomy, the modified sham feeding-induced increment in plasma pancreatic polypeptide was significantly decreased and observed only in seven of 12 patients. Four to five years after parietal cell vagotomy all subjects responded to modified sham feeding with pancreatic polypeptide increment similar to that before vagotomy and in three of 12 patients acid response to modified sham feeding was seen. This study indicates that truncal vagotomy eliminates gastric acid and plasma pancreatic polypeptide responses to vagal excitation while parietal cell vagotomy abolishes gastric acid response and reduces temporarily the pancreatic polypeptide response to modified sham feeding (possibly because of transient impairment of the vagal innervation of the pancreas). (2) A high ratio of basal to maximal acid output in non-operated duodenal ulcer patients is not associated with a low acid response to modified sham feeding, nor with a high pancreatic polypeptide concentration, and (3) Restitution of the pancreatic polypeptide response to modified sham feeding five years after parietal cell vagotomy does not indication ineffective denervation of the parietal cells.

Role of endogenous prostaglandins in duodenal alkaline response to luminal hydrochloric acid or arachidonic acid in conscious dogs

Duodenal secretion of HCO-3 and luminal release of PGE2 were measured in conscious dogs. The results show that the HCO-3 secretion is closely correlated with the luminal release of PGE2 and that both the HCO-3 and the PGE2 outputs increase dose-dependently after topical application of hydrochloric acid or arachidonic acid. Indomethacin reduced basal HCO-3 and PGE2 release and prevented their increase in response to hydrochloric acid or arachidonic acid. We conclude that mucosal PGE2 plays an important role in the alkaline secretion from the duodenum.

Studies on the localization of secretin release from canine intestine

In conscious dogs with chronic pancreatic fistulas, duodenal perfusion with HCl (16 mmol/h) stimulated pancreatic HCO-3 secretion to a similar degree as exogenous secretin (2 U/kg X h), while meat feeding (500 g) and duodenal perfusion with oleate (16 mmol/h) increased this secretion to about 58 and 43% of the highest response to secretin. Plasma secretin increments with duodenal HCl, feeding and duodenal oleate amounted to about 45, 13 and 8% of that achieved with secretin, producing the highest HCO-3 response. Perfusion of the in situ intestine with HCl at gradually increasing rates produced HCO-3 responses similar to those induced by exogenous secretin in graded doses, but the increments in plasma secretin with duodenal HCl were only about half those obtained with exogenous secretin, producing an equal rate of HCO-3 secretion. HCl perfusion of isolated Thiry loops made of the duodenojejunal portion also stimulated the HCO-3 secretion in a dose-dependent way, but raised plasma secretin only to about half that attained with secretin, producing a similar secretory rate. HCl in the proximal duodenal and distal jejunal loop slightly stimulated the HCO-3 secretion without affecting plasma secretin, and that in the ileal loop was without any effect on the pancreatic or plasma secretin. This study provides evidence that (a) endogenous secretin is released by feeding and duodenal perfusion with HCl and oleate, but only HCl appears to release sufficient amounts of secretin to drive the HCO-3 secretion, and (b) the release of secretin is confined mainly to the distal duodenum and proximal jejunum.

Effects of somatostatin-14 and somatostatin-28 on plasma hormonal and gastric secretory responses to cephalic and gastrointestinal stimulation in man

This study was designed to determine the influence of cephalic and gastrointestinal meal stimulation on plasma levels of somatostatin-like immunoreactivity (SLI) and to compare plasma hormonal and gastric secretory effects of somatostatin-14 (SS-14) and its putative prohormone, somatostatin-28 (SS-28), in humans. Cephalic stimulation induced by modified sham feeding did not affect plasma SLI, whereas a gastric liver extract meal caused a significant increase in SLI. Infusion of SS-28 dose-dependently suppressed gastric acid, serum gastrin, and plasma pancreatic polypeptide (PP) responses to cephalic and gastrointestinal stimulation. SS-28 was equipotent with SS-14 as gastric inhibitor when compared on the basis of molar doses infused but was 4-10 times less potent on the basis of plasma SLI concentrations obtained. A lower and more physiological dose of SS-14 (75 pmol/kg-h) reduced gastric acid and PP responses but failed to affect the serum gastrin response to a meal; whereas a larger, pharmacological dose (500 pmol/kg-h) also suppressed serum gastrin responses. We conclude that meal releases SLI into the circulation and that SS-28 mimics the gastric secretory and plasma hormonal effects of SS-14 but is several times less potent than SS-14 in terms of circulating hormone levels.

Effect of enkephalin and naloxone on gastric acid and serum gastrin and pancreatic polypeptide concentrations in humans

The effects of a synthetic enkephalin analogue with prolonged opioid activity, D-ala-2-enkephalin (ala-enk) and naloxone given alone or in combination, on vagally, pentagastrin- and histamine-induced gastric secretion and plasma hormonal responses to vagal stimulation have been studied in healthy subjects. D-ala-2-enkephalin reduced basal gastric acid and pepsin secretion, and caused a dose-dependent inhibition of gastric secretory responses to modified sham-feeding and pentagastrin but not to histamine. It increased serum gastrin concentration and suppressed plasma pancreatic polypeptide response to modified sham-feeding. Naloxone alone at lower dose levels did not affect gastric secretion and plasma hormonal concentrations but at higher doses it reduced both basal and modified sham-feeding-induced secretion. When combined with ala-enk it reversed in part gastric secretory and plasma hormonal changes induced by this peptide during modified sham-feeding and pentagastrin stimulation. These results indicate that (1) stable enkaphalin analogue inhibits basal and vagally or pentagastrin-induced gastric secretion, and affects plasma hormonal response to vagal stimulation, at least in part, via activation of opioid receptors and (2) endogenous opioid substances may be involved in the stimulation of gastric secretion in man.

Comparison of enkephalin and atropine in the inhibition of vagally stimulated gastric and pancreatic secretion and gastrin and pancreatic polypeptide release in dogs

Enkephalins have been detected in vagal nerves and myenteric plexus neurons but no study has been performed to determine their action on vagally stimulated gastric and pancreatic secretion. In this study we infused IV methionine-enkephalin (Met-enk) alone, naloxone (a pure opiate antagonist) alone, or their combination before, during and after vagal stimulation in 4 dogs with esophageal, gastric and pancreatic fistulas. For the comparison, atropine was given before, during and after vagal stimulation in the same animals. Vagal stimulation was obtained by 15 min sham-feeding, which produced an increase in gastric H+ output to a peak of about 75% of the maximal response to pentagastrin and pancreatic protein secretion amounting to about 71% of the maximal response to caerulein. It was accompanied by a significant rise in serum gastrin and pancreatic polypeptide (PP) levels. Met-enk inhibited significantly both gastric H+ and pancreatic protein secretion and reduced plasma PP but not gastrin levels. Similar effects were obtained after the administration of atropine. The effects of Met-enk were partly reversed by the addition of naloxone. We conclude that (1) enkephalin suppresses vagally stimulated gastric and pancreatic secretion and plasma PP release; (2) these secretory effects of enkephalin seem to be mediated by opiate receptors and could be explained by its inhibitory action on acetylcholine release ("anticholinergic" action) in the stomach and the pancreas.

Organ removal and disappearance half-time of synthetic human pancreatic polypeptide

Human pancreatic polypeptide (HPP) was infused into 6 anesthetized dogs at a constant dose of 1.0 micrograms/kg/h over 60 min. Blood samples for RIA of pancreatic polypeptide were taken repeatedly from a carotid artery, jugular vein, femoral vein, renal vein and mesenteric vein. The calculated tissue removal of HPP in a single passage through these four vascular beds ranged from 24 to 40% and did not differ significantly among them. Mean disappearance half-time on stopping the infusion was 4.5 +/- 0,8 min. The results indicate that HPP is removed at all of the capillary beds tested.