Surgical techniques and postoperative management to prevent postoperative pancreatic fistula after pancreatic surgery

Postoperative pancreatic fistula (POPF) is one of the most severe complications after pancreatic surgeries. POPF develops as a consequence of pancreatic juice leakage from a surgically exfoliated surface and/or anastomotic stump, which sometimes cause intraperitoneal abscesses and subsequent lethal hemorrhage. In recent years, various surgical and perioperative attempts have been examined to reduce the incidence of POPF. We reviewed several well-designed studies addressing POPF-related factors, such as reconstruction methods, anastomotic techniques, stent usage, prophylactic intra-abdominal drainage, and somatostatin analogs, after pancreaticoduodenectomy and distal pancreatectomy, and we assessed the current status of POPF. In addition, we also discussed the current status of POPF in minimally invasive surgeries, laparoscopic surgeries, and robotic surgeries.

[Application of somatulin in the treatment of complications after operations on the pancreatic gland]

The results of treatment of 32 patients with complications, occurring after operations on pancreatic gland, ended by the external pancreatic fistula formation, in the complex of their treatment Somatulin, somatostatin analogue of prolonged action, were studied. Application of the treatment tactics proposed have permitted to achieve the fistula closure in all the patients without the operative intervention. The terms of the pancreatic fistula closure after Somatulin injection had constituted 5-20 days, (11.1 +/- 0.7) days at average.

Translocation of pancreatic juice after ischemia and reperfusion of the intestines and the effects of gabexate mesilate (FOY) in rats

OBJECTIVES

To evaluate pancreatic juice translocation after ischemia and reperfusion (I/R) of the superior mesenteric artery (SMA).

METHODS

Ischemia was induced by clamping the rat SMA for 40 minutes, after which flow was restored and the SMA reperfused for 300 minutes. The blood levels of amylase and lipase were measured to reflect the dislocation of pancreatic juice. Organ injury parameters, such as the blood concentrations of alanine aminotransferase, creatinine kinase, and creatinine and the lung weight/body weight ratio were measured as well as inflammatory parameters such as tumor necrosis factor, hydroxyl radical, and nitric oxide levels.

RESULTS

Organ injury and inflammatory parameters all increased significantly after I/R. Reperfusion of the intestine also induced a significant increase in the levels of pancreatic juice in the blood. After administration of the enzyme inhibitor, gabexate mesilate (FOY; 10 mg/kg), by injection into the duodenum, organ injury was significantly attenuated.

CONCLUSIONS

These findings suggested that I/R of the SMA induced multiple organ injuries that appeared to be dependent on the translocation of pancreatic enzymes.

Obestatin stimulates the secretion of pancreatic juice enzymes through a vagal pathway in anaesthetized rats - preliminary results

Obestatin is a 23 amino acid peptide derived from the preproghrelin precursor, and originally purified from the rat stomach mucosa. It was shown that obestatin may counteract the effects of its sister peptide, ghrelin, on food intake and gastrointestinal motility but the other roles in controlling the gastrointestinal function remain unknown. The aim of the present study was to determine the influence of exogenous obestatin on the secretion of pancreatic juice. In anesthetized male Wistar rats the external jugular vein was catheterized, and the common biliary-pancreatic duct was cannulated with polyethylene tubing for collection of pancreatic-biliary juice (P-BJ). Obestatin boluses (30, 100 and 300 nmol/kg b. wt.) were injected intravenously or intraduodenally every 30 min. Obestatin was also administered in vagotomized (subdiaphragmatic vagotomy) rats. In the examined rats, obestatin intravenous and intraduodenal boluses did not affect the P-BJ volume. On the other hand, obestatin boluses increased the protein output and trypsin activity. Vagotomy abolished the effects of exogenous obestatin administration. In conclusion, the present study demonstrates for the first time that exogenous obestatin may stimulate the secretion of pancreatic juice enzymes. The effect is dose-dependent and requires intact vagal supply.

The papilla of Vater just below the pylorus presenting as recurrent duodenal ulcer bleeding

The papilla of Vater emptying into the duodenal bulb site is extremely rare and considered an aberrant condition. We report here a case with recurrent duodenal ulcer bleeding associated with this anomaly. A 42-year-old man was admitted to St. Mary Hospital because of tarry stool for three days. Despite no documented etiology to explain recurrent ulceration, the patient had about ten episodes of ulcer bleeding since 1995. On duodenoscopy, 1.0 x 0.6 cm sized active stage duodenal ulcer with oozing was observed at the posterior wall side below the pylorus. The papilla of Vater was bulging just below the pylorus. Bile juice was excreted from its opening. Pancreatic duct and common bile duct, which drained into the bulb site, were observed on ERCP. In this report, we show that recurrent duodenal ulcer can be associated with the papilla of Vater just below the pylorus.

Effect of short chain fatty acids infused intraileally on interdigestive exocrine pancreatic secretions in growing pigs

The effect of intraileally infused short chain fatty acids (SCFA) and saline as control on the exocrine pancreatic secretions during the interdigestive phase was studied using three 8-weeks-old piglets. Pigs were surgically fitted with a pancreatic duct catheter, re-entrant duodenal T-cannula for collection and subsequent return of pancreatic juice, and with an infusion T-cannula at the distal ileum. Saline as control, 5.0 and 10.0 mm butyrate, 7.5 and 15.0 mm propionate and 85.0 and 170.0 mm acetate were infused at 2 ml/kg body weight (BW) for 30 min into the ileum of overnight fasted piglets via ileal T-cannula. The calculated volume of infusates was administrated in five equal bolus at 6 min intervals over a period of 30 min. The pancreatic juice was collected 60 and 30 min before and 30, 60, 90 and 120 min after the start of infusion. The trypsin (p = 0.07, p > 0.15 respectively) and protein (p > 0.15, p = 0.05 respectively) outputs immediately decreased after the infusion of acetate at the dose of 85.0 and 170.0 mm, respectively, whereas pancreatic juice outflow (p > 0.15) was not significantly affected when compared with levels 30 min before infusion. After the infusion of butyrate at the dose of 5.0 mm, trypsin (p = 0.01) and protein (p = 0.12) outputs increased immediately whereas pancreatic juice outflow was not affected (p > 0.15) in comparison with levels 30 min before infusion. No significant differences were observed after infusion of butyrate at the dose of 10 mm for the pancreatic juice outflow, trypsin and protein outputs when compared with the level before infusion, although these values were numerically lower immediately after the infusion. The pancreatic juice outflow increased (p = 0.03) after the infusion of propionate at the dose of 7.5 mm and decreased (p = 0.005) immediately after the infusion of propionate at the dose of 15.0 mm when compared with the levels 30 min before the infusions. After the infusion of propionate at the dose of 7.5 or 15.0 mm for the output of protein and trypsin, no significant differences (p > 0.15) were observed when compared with levels 30 min before infusion. In summary, the intraileal infusion of SCFA at different doses exerts a short-term and moderate effect on the interdigestive exocrine pancreatic secretions in pigs.

The effect of moderate sedation on exocrine pancreas function in normal healthy subjects: a prospective, randomized, cross-over trial using the synthetic porcine secretin stimulated Endoscopic Pancreatic Function Test (ePFT)

BACKGROUND

We have developed a purely endoscopic collection method for the assessment of pancreatic secretory function (ePFT). The pancreatic secretory effects of sedation medications utilized during endoscopic procedures are not completely known.

AIMS

To study the effect of moderate sedation on the exocrine pancreas gland in a prospective, randomized trial.

METHODS

Healthy volunteers were randomized by computers to one of two treatments (A-no sedation, B-sedation) in period 1 and crossed-over to the other treatment in period 2 with a minimal washout interval of 7 days. Sedation dosage was standardized for each patient based on age, gender and weight from a previously published dosing nomogram. Synthetic porcine secretin (ChiRhoClin, Inc., Burtonsville, Maryland) was used as the pancreatic stimulant. Duodenal fluid samples were aspirated via the endoscope every 5 min for 1 h and sent on ice to our hospital laboratory for the measurement of pancreatic secretory electrolyte concentrations by autoanalyzer.

RESULTS

A total of 17 healthy volunteers were enrolled. Sixteen subjects (8 males and 8 females) completed the randomized prospective trial. Median intravenous meperidine and midazolam sedation dose was 62.5 mg and 2.5 mg, respectively. Maximum pancreatic juice flow occurred during the early phase of secretion and maximum bicarbonate concentration occurred during the late phase of secretion. Analysis of the electrolyte composition of the endoscopically collected duodenal drainage fluid revealed a constant cation concentration for both sodium and potassium over the 1 h collection period. The anions, chloride and bicarbonate, exhibited a reciprocal relationship identical to that seen in traditional gastroduodenal tube collection studies. There was no statistical difference observed between the sedation and no sedation groups. The estimated total bicarbonate output (area under curve, AUC) for the sedated and non-sedated groups were 5,017 meq + 724 (range 3,663-6,173) and 5,364 meq +/- 583 (range 4,323-6563) respectively (p= 0.0656). The mean peak bicarbonate concentrations for sedated (n = 8) versus non-sedated (n = 8) groups were 103 +/- 11 meq/L (range 78-125) and 106 +/- 11 meq/L (range 87-138), respectively (p= 0.1346). There was excellent correlation of peak bicarbonate concentrations when sedation and no sedation groups were compared (r= 0.744, p < 0.05; Spearman rank correlation). There were no episodes of pancreatitis.

CONCLUSIONS

(a) Moderate sedation used for upper endoscopy does not effect the clinical diagnostic parameters (peak bicarbonate concentration or total bicarbonate output) utilized to diagnose pancreatic insufficiency. (b) Analysis of duodenal drainage fluid collected endoscopically after synthetic secretin stimulation produces an identical pancreatic secretory curve described with traditional gastroduodenal tube collection methods.

Effects of gabexate mesilate (FOY) on amylase and phospholipase A2 in human serum and pancreatic juice

The precise inhibitory action of gabexate mesilate (GM) on the various pancreatic enzymes remains unclear. We designed this study to investigate the enzyme inhibitory action of GM in the serum and directly in the pancreatic juice. We observed 16 cases with postoperative pancreatic drainage. Patients were randomly assigned to one of two groups, to receive GM at a dose of 600 mg/24 hr (treated group: 8 patients) or a physiological solution (control group: 8 patients) by continuous intravenous infusion. In both groups pancreatic juice and serum were sampled three times: before infusion began (T0) and at 12 hr (T1) and 24 hr after infusion ended (T2). At the end of the study, seven patients received octreotide and the volume of pancreatic secretion was determined. No statistical difference was observed in serum amylase and phospholipase A2 activity in the treated and control groups. On the contrary, amylase and phospholipase A2 activity in the pancreatic juice diminished significantly only in the treated group, and in these patients a GM metabolite was also detectable in the pancreatic secretion. The volume of pancreatic secretion decreased only after infusion of octreotide. The enzyme inhibition in the pancreatic gland itself and the central role of inhibition of phospholipase A2 in the enzyme cascade responsible for activating other proteases, confirm the therapeutic use of GM in acute pancreatitis. An association of GM and octreotide during acute pancreatitis should be useful because of their different mechanisms.

Gabexate mesilate (FOY) inhibition of amylase and phospholipase A(2) activity in sow pancreatic juice

We designed this study in sows to investigate the enzyme inhibitory action of gabexate mesylate (GM) directly in the pancreatic juice. We studied 16 sows, each weighing about 130 kg. The pancreatic duct was identified and cannulated to collect the pancreatic juice. Sows in the treated group received intravenous GM infusion at a dose of 1000 mg over 24 h. Control sows underwent the same sampling schedule while receiving physiological solution. GM inhibited the two pancreatic enzymes amylase and phospholipase A(2) (PA(2)) in pancreatic juice. Thus, the enzyme inhibition in the pancreatic gland itself and the central role of (PA(2)) inhibition in enzyme cascade responsible for activating other proteases confirm the therapeutic use of GM in acute pancreatitis.

Modulation of pancreatic enzyme secretion by melatonin and its precursor; L-tryptophan. Role of CCK and afferent nerves

Melatonin, a pineal hormone, is also produced in the gastrointestinal tract. Melatonin receptors have been detected in the stomach, intestine and pancreas. This indole inhibits insulin secretion but its role in the physiological modulation of exocrine pancreatic function is yet unknown. The aim of this study was to evaluate the pancreatic secretory effect of melatonin and its precursor; L-tryptophan given intraduodenally (i.d.) to the conscious rats with intact or capsaicin deactivated sensory nerves. CCK(1) receptor antagonist; tarazepide, was used in the part of the study to determine the involvement of CCK in the secretory effects of melatonin. The secretory studies were performed on awaken rats surgically equipped with silicone catheters, one of them was inserted into pancreato-biliary duct, the other one--into duodenum. Melatonin (1, 5 or 25 mg/kg) or L-tryptophan (10, 50 or 250 mg/kg) were administered i.d. Samples of pancreatic juice were collected in 15 minutes aliquots. Tarazepide (2,5 mg/kg i.p.) was given to the rats 15 min prior to the administration of melatonin or L-tryptophan. Neurotoxic dose of capsaicin (100 mg/kg s.c.) was used to deactivate afferent nerves and thus to assess the role of these nerves in the melatonin-induced pancreatic enzyme secretion. Administration of melatonin (1, 5 or 25 mg/kg i.d.) or L-tryptophan (10, 50 or 250 mg/kg i.d.) significantly increased pancreatic amylase outputs. Deactivation of sensory nerves by capsaicin or administration of CCK(1) - receptor antagonist; tarazepide, reversed the stimulatory effects of melatonin or L-tryptophan on pancreatic secretory function. Administration of melatonin or its amino-acid precursor to the rats resulted in the significant and dose-dependent rises of melatonin and CCK plasma levels. We conclude that melatonin or its precursor; L-tryptophan stimulates pancreatic enzyme secretion via stimulation of CCK release and activation of duodeno-pancreatic reflexes.

Effect of Bak Foong pills on exocrine pancreatic-bile secretion

We have recently demonstrated that Bak Foong Pills (BFP), a well-known Chinese medicine widely used for treating gynecological disorders, stimulates human colonic epithelial anion secretion, which was mediated by intracellular cAMP and Ca(2+). The present study further investigated the effect of BFP on exocrine pancreatic-bile secretion using in vivo and in vitro approaches. Duodenal infusion of BFP ethanol extract (1 g/kg) in rats produced increases in the volume and protein output of pancreatic-bile juice, but did not affect its pH. Surgical ablation of vagal neural pathway slightly reduced the effect of BFP on the protein output and volume, indicating that the vagal nerve pathway was not the major player in medicating the effect of BFP on exocrine pancreatic-bile secretion. Using CAPAN-1 cell line, a human pancreatic duct cell line, in conjunction with the short-circuit current (I(SC)) measurements, we further demonstrated that BFP could directly stimulate pancreatic HCO(3)(-) secretion. Basolateral addition of BFP (600 microg/ml) produced averaged charges transported of 2100+/-382.5 microC/cm(2), which was blocked by apical addition of Cl(-) channel blocker. Removal of HCO(3)(-) from the Krebs-Henseleit (K-H) solution inhibited the BFP-induced I(SC) by more than 95%. The present results suggest that BFP could improve digestive function by stimulating pancreatic protein and HCO(3)(-) secretion.

The bifunctional rat pancreatic secretory trypsin inhibitor/monitor peptide provides protection against premature activation of pancreatic juice

BACKGROUND

In the rat, two forms of the pancreatic secretory trypsin inhibitor, PSTI-I and PSTI-II, are secreted into pancreatic juice. It is assumed that their role is to protect the pancreas from premature activation of the protease-rich pancreatic juice. In the small intestine, PSTI-I, also called 'monitor peptide', is thought to have a different role: PSTI-I competes with protein for activated trypsin. In the presence of a protein-rich meal, free PSTI induces a release of cholecystokinine from the intestine.

METHODS

To investigate whether its role as monitor peptide is compatible with the inhibitory, protective function in the pancreas, PSTI-I was chemically synthesized and then renatured.

RESULTS

The peptide was almost completely trypsin resistant and exhibited a dose-dependent inhibitory activity to bovine and partially purified rat trypsin. Furthermore, experiments with trypsin- and endopeptidase-activated pancreatic juice demonstrated that its inhibitory capacity was sufficient to prevent premature activation. Binding studies of (125)I-labeled PSTI-I with the putative intestinal receptor using isolated membranes indicated the presence of high-affinity binding sites (k(d) = 5 x 10(-8)M). Binding of PSTI-I could be competed with excess PSTI-I or trypsin. In a biological assay system, injections of PSTI-I displayed monitor peptide activity by inducing a dose-dependent trypsinogen release from the pancreas.

CONCLUSION

Our experiments support a dual function of PSTI-I: monitoring protein in the gut due to its 'moderate' affinity for trypsin and a protective role in the pancreas.

Role of leptin in the control of postprandial pancreatic enzyme secretion

Leptin released by adipocytes has been implicated in the control of food intake but recent detection of specific leptin receptors in the pancreas suggests that this peptide may also play some role in the modulation of pancreatic function. This study was undertaken to examine the effect of exogenous leptin on pancreatic enzyme secretion in vitro using isolated pancreatic acini, or in vivo in conscious rats with chronic pancreatic fistulae. Leptin plasma level was measured by radioimmunoassay following leptin administration to the animals. Intraperitoneal (i.p.) administration of leptin (0.1, 1, 5, 10, 20 or 50 microg/kg), failed to affect significantly basal secretion of pancreatic protein, but markedly reduced that stimulated by feeding. The strongest inhibition has been observed at dose of 10 microg/kg of leptin. Under basal conditions plasma leptin level averaged about 0.15 +/- 0.04 ng/ml and was increased by feeding up to 1.8 +/- 0.4 ng/ml. Administration of leptin dose-dependently augmented this plasma leptin level, reaching about 0.65 +/- 0.04 ng/ml at dose of 10 microg/kg of leptin. This dose of leptin completely abolished increase of pancreatic protein output produced by ordinary feeding, sham feeding or by diversion of pancreatic juice to the exterior. Leptin (10(-10)-10(-7) M) also dose-dependently attenuated caerulein-induced amylase release from isolated pancreatic acini, whereas basal enzyme secretion was unaffected. We conclude that leptin could take a part in the inhibition of postprandial pancreatic secretion and this effect could be related, at least in part, to the direct action of this peptide on pancreatic acini.

Atrial natriuretic factor stimulates exocrine pancreatic secretion in the rat through NPR-C receptors

Increasing evidence supports the role of atrial natriuretic factor (ANF) in the modulation of gastrointestinal physiology. The effect of ANF on exocrine pancreatic secretion and the possible receptors and pathways involved were studied in vivo. Anesthetized rats were prepared with pancreatic duct cannulation, pyloric ligation, and bile diversion into the duodenum. ANF dose-dependently increased pancreatic secretion of fluid and proteins and enhanced secretin and CCK-evoked response. ANF decreased chloride secretion and increased the pH of the pancreatic juice. Neither cholinergic nor adrenergic blockade affected ANF-stimulated pancreatic secretion. Furthermore, ANF response was not mediated by the release of nitric oxide. ANF-evoked protein secretion was not inhibited by truncal vagotomy, atropine, or Nomega-nitro-l-arginine methyl ester administration. The selective natriuretic peptide receptor-C (NPR-C) receptor agonist cANP-(4-23) mimicked ANF response in a dose-dependent fashion. When the intracellular signaling coupled to NPR-C receptors was investigated in isolated pancreatic acini, results showed that ANF did not modify basal or forskolin-evoked cAMP formation, but it dose-dependently enhanced phosphoinositide hydrolysis, which was blocked by the selective PLC inhibitor U-73122. ANF stimulated exocrine pancreatic secretion in the rat, and its effect was not mediated by nitric oxide or parasympathetic or sympathetic activity. Furthermore, CCK and secretin appear not to be involved in ANF response. Present findings support that ANF exerts a stimulatory effect on pancreatic exocrine secretion mediated by NPR-C receptors coupled to the phosphoinositide pathway.

Effect of orlistat on fat absorption in rats: A comparison of normal rats and rats with diverted bile and pancreatic juice

Orlistat is a specific inhibitor of pancreatic and gastric lipases leading to decreased absorption of fat. In the present study, we measured the effect of orlistat on lymphatic fat transport in rats following intake of oils very different in FA composition and TAG structure, and compared this with the transport in normal rats and rats with fat malabsorption. Rats were subjected to cannulation of the main mesenteric lymph duct, and a feeding catheter was inserted into the stomach. In addition, malabsorbing rats were cannulated in the common bile and pancreatic duct. Emulsified safflower, fish, and randomized oils were administered, and lymph was collected for 24 h and analyzed for FA composition. Administration of 25 mg orlistat together with the dietary oils resulted in very small changes from baseline lymphatic transport, indicating that inhibition of the fat absorption was almost complete and furthermore that the source of fat had no influence on the inhibitory effect of orlistat. Orlistat did not interfere with the absorption of the hydrolysis products, since high absorption of sn-2 MAG and FFA (oleic acid) mixed with orlistat was observed. The baseline lymphatic transport in the orlistat group was higher than in the malabsorbing group, but this was the result of generally lower transport of endogenous FA in the malabsorbing group, presumably caused by the absence of bile FA. The transport of FA in normal rats was several-fold higher than the transport after orlistat addition and in malabsorbing rats. Thus, this study showed that orlistat inhibited fat hydrolysis, and thereby lymphatic absorption, almost completely independently of the fat administered.

Exogenous leptin inhibits the secretion of pancreatic juice via a duodenal CCK1-vagal-dependent mechanism in anaesthetized rats

Leptin originally described as product of the ob gene has been shown to be expressed in various tissues including the gastrointestinal tract. In this study, we investigated the influence of leptin on the secretion of pancreatic juice in biliary-pancreatic duct cannulated anaesthetised rats and in dispersed rat pancreatic acini in vitro. Exogenous leptin was given in boluses intravenously with or without CCK-8 (12 pmol kg(-1) body weight) in the presence or absence pharmacological CCK(1) receptor blockade, cervical vagotomy, and capsaicin pre-treatment. Administration of leptin (0.1, 1 and 10 microg kg(-1) body weight) did not affect the volume of bile and pancreatic juice while the protein and trypsin outputs were reduced in a dose-dependent manner. In the rats, leptin inhibited CCK-8 stimulated protein and trypsin outputs stronger than the basal pancreatic secretion. The inhibition by leptin was abolished by the pharmacological CCK(1) receptor blockade, cervical vagotomy, and capsaicin pre-treatment. In contrast, leptin did not affect basal and CCK-8-stimulated amylase release from the dispersed rat pancreatic acini in vitro. In conclusion, the results of the present study suggest that leptin does not act directly on the rat pancreatic acinar cells but inhibits the secretion of pancreatic enzymes acting indirectly via a neurohormonal CCK-vagal-dependent mechanism.

Purification of classical pancreatic lipase from dog pancreas

The purification of canine classical pancreatic lipase from canine pancreatic juice, but not from pancreatic tissue, has been reported previously. Given the logistic difficulties associated with collection of pancreatic juice in dogs and efforts to minimize experiments in live animals the objective of this project was to purify canine classical pancreatic lipase from dog pancreas. Dog pancreata were collected from research dogs that had been sacrificed for unrelated research projects. Pancreatic tissue was delipidated using organic solvents. The delipidated pancreatic extract was further purified by extracting the enzymes in a Tris-buffer containing two different protease inhibitors, benzamindine and phenylmethylsulfonyl fluoride (PMSF), followed by anion exchange chromatography, gel-filtration, and cation exchange chromatography. The purified protein showed a single band on sodium dodecyl sulfate polyacrylamide gel electrophoresis with a molecular weight of approximately 50.7. Isoelectric focusing showed isoelectric points ranging from 6.0 to 6.2. N-terminal amino acid sequencing of the first 25 amino acid residues showed the sequence Lys-Glu-Val-X-Phe-Pro-Arg-Leu-Gly-X-Phe-Ser-Asp-Asp-Ser-Pro-Trp-Ala-Gly-Ile-Val-Glu-Arg-Pro-Leu. This sequence showed close homology with classical pancreatic lipase in pigs, horses, and human beings. We conclude that canine classical pancreatic lipase can be successfully purified from canine pancreatic tissue.

[Natural history of the pancreatic stump after duodenopancreatectomy of the pancreatic head]

Major complications following pancreaticoduodenectomy are thought to be chiefly associated with exocrine secretion of the pancreatic remnant which is not well known. This work aims to assess the exocrine secretion of the pancreatic remnant within the early post-operative period.

PATIENTS AND METHODS

Seventy-five patients undergoing pancreaticoduodenectomy for presumed tumour were included in a prospective multicentre study. A tube was inserted in the pancreatic duct at the time of construction of the pancreatic anastomosis. Peripancreatic drainage was routinely used. Pancreatic juice and peripancreatic drainage fluid were collected and measured and pancreatic enzyme monitored. For 7 days patients received total parenteral nutrition and continuous infusion of randomly Somatostatin 14 (S-14) at a dose of 6 mg/24 h (days 1-6) and 3 mg/24 h (day 7) or matching placebo. Pancreatic fistula was defined as a daily drainage of more than 100 cc of amylase-rich fluid after day 3, persisting after day 12 or associated with symptoms or needing specific treatment.

RESULTS

Daily output of pancreatic juice was low during the first postoperative day and then increased gradually until day 5. A high enzyme concentration was observed in pancreatic juice on the first post-operative day. S-14 infusion resulted in a significant decrease of both pancreatic fistula rate and enzyme concentration in peripancreatic fluid.

CONCLUSIONS

During the first postoperative days, the outflow of the exocrine secretion of the pancreatic remnant is low but contains a high enzyme concentration with significant leaks within the peripancreatic area. S-14 infusion results in a decrease of pancreatic juice leaks from the pancreatic remnant.

Food and secretagogue stimulation decrease the digestive enzyme content remaining in the rat pancreas

The aim of the study reported here was to investigate changes in the digestive enzyme content in the pancreas after food and secretagogue stimulation. Rats from which food had been withheld overnight were either fed (between 6 and 8 a.m.) or not before euthanasia and pancreatic excision (at 8 a.m.: 21 not fed and 21 fed) and at 4 (12 p.m.: six not fed and six fed) and 8 h later (4 p.m.: six not fed and six fed). Another 16 rats were anesthetized, fitted with jugular vein and pancreatic duct catheters, and infused with the secretagogues, CCK-33 and secretin, during 1.5 h of pancreatic juice collection before euthanasia and pancreatic excision. The pancreata were homogenized, and total soluble protein and individual enzyme (trypsin and amylase) tissue contents were analyzed. Results indicated lower amounts of protein and enzymes remaining in the pancreata of the fed, compared with non-fed rats. Enzyme values indicated recovery within four hours in fed rats, but non-fed rats also had increased values during daytime. High enzyme secretion during the high dose of hormonal stimulation was reflected in lower enzyme values remaining in the pancreas, compared with that in response to low-dose stimulation. Results indicated that stimulation of the pancreas, either by food ingestion or exogenous secretagogues, lowers the amounts of digestive enzymes remaining in the pancreas, and imply that stimulation and circadian rhythms influence the pancreatic enzyme content at euthanasia. This finding should be borne in mind in interpretation of data from pancreatic studies.

MEK inhibits secretin release and pancreatic secretion: roles of secretin-releasing peptide and somatostatin

We investigated the mechanism of action of methionine enkephalin (MEK) on HCl-stimulated secretin release and pancreatic exocrine secretion. Anesthetized rats with pancreatobiliary cannulas and isolated upper small intestinal loops were perfused intraduodenally with 0.01 N HCl while bile and pancreatic juice were diverted. The effect of intravenous MEK on acid-stimulated secretin release and pancreatic exocrine secretion was then studied with or without coinfusion of naloxone, an anti-somatostatin (SS) serum, or normal rabbit serum. Duodenal acid perfusate, which contains secretin-releasing peptide (SRP) activity, was collected from donor rats with or without pretreatment with MEK, MEK + naloxone, or MEK + anti-SS serum, concentrated by ultrafiltration, and neutralized. The concentrated acid perfusate (CAP), which contains SRP bioactivity, was infused intraduodenally into recipient rats. MEK increased plasma SS concentration and inhibited secretin release and pancreatic fluid and bicarbonate secretion dose-dependently. The inhibition was partially reversed by naloxone and anti-SS serum but not by normal rabbit serum. In recipient rats, CAP increased plasma secretin level and pancreatic secretion. CAP SRP bioactivity decreased when it was collected from MEK-treated donor rats; this was partially reversed by coinfusion with naloxone or anti-SS serum. These results suggest that in the rat, MEK inhibition of acid-stimulated pancreatic secretion and secretin release involves suppression of SRP activity release. Thus the MEK inhibitory effect appears to be mediated in part by endogenous SS.

Early changes in islet hormone secretion in the hamster pancreatic cancer model

The diabetic state that is seen at a high frequency in association with pancreatic cancer is characterized by elevated plasma levels of several islet hormones and by marked insulin resistance. Both the diabetic state and insulin sensitivity improve after tumor removal by sub-total pancreatectomy. Impaired glucose tolerance has also been found in the hamster pancreatic cancer model, but conflicting data regarding islet function have been reported. In order to further investigate islet function and secretion during early development of pancreatic cancer, we measured the concentrations of insulin, glucagon, somatostatin, and islet amyloid polypeptide (IAPP) in plasma, pancreatic tissue, and secretin-stimulated pancreatic juice at 12 and 27 weeks after the ductal-cell-specific carcinogen, BOP had been used to induce tumors in Syrian golden hamsters. At 12 weeks after BOP, plasma glucagon levels were significantly increased. An exaggerated plasma-glucose response and concomitant hyperinsulinemia were observed at 27 but not 12 weeks after BOP. Plasma IAPP concentrations, but not glucagon or somatostatin, were elevated at 27 weeks. Tissue concentrations of IAPP were substantially reduced in BOP-treated hamsters at 27 weeks. No differences in hormone concentrations were seen in pancreatic juice from the two groups at either of the two time points investigated. The study showed that islet hormone changes accompany the early development of pancreatic tumors in the hamster pancreatic model. The hormone changes and apparent insulin resistance resemble the metabolic changes found in humans with pancreatic cancer.

Caseinomacropeptide specifically stimulates exocrine pancreatic secretion in the anesthetized rat

The effect of caseinomacropeptide (CMP) (the [106-169] fragment of kappa-casein produced during digestion of milk protein), was studied in anesthetized rats using bile diversion for a pure pancreatic juice collection system. Intraduodenal administration of CMP induced a dose-related specific stimulation of pancreatic secretion which was nearly abolished by devazepide, atropine, hexamethonium, vagotomy or perivagal capsaicin pretreatment. Moreover, CMP did not inhibit in vitro trypsin activity. These results demonstrate that CMP is more likely to stimulate pancreatic secretion specifically through cholecystokinin release and activation of a vago-vagal cholinergic reflex loop than by inhibition of luminal trypsin, in anesthetized rats.

Pancreatic secretory response to feeding in the calf: CCK-A receptors, but not CCK-B/gastrin receptors are involved

In bovine species, as in human, the pancreas predominantly expresses cholecystokinin-B (CCK-B)/gastrin receptors. However, the role of this receptor in the regulation of meal-stimulated pancreatic enzyme release has not been determined. In milk-fed calves, we previously described prandial patterns of exocrine pancreatic secretion and a long prefeeding phase was observed. The present study was aimed at determining both the role of external stimuli in the outset of the prefeeding phase and the implication of pancreatic CCK-A and CCK-B/gastrin receptors in the mediation of pancreatic response to feeding. The first objective was studied by suppressing external stimuli associated with food intake (unexpected meal) and the second by infusing highly specific and potent antagonists of CCK-A (SR 27897) and CCK-B/gastrin (PD 135158) receptors during the prandial period. When calves were given an unexpected meal, the long prefeeding increase in pancreatic secretion was absent. SR 27897 (but not PD 135158) inhibited the preprandial phase and greatly reduced postprandial pancreatic juice and enzyme outflows. The expectancy of a meal seemed to elicit an increased pancreatic response right before a meal and CCK-A receptors may mediate this information via neural pathways. The implication of CCK and CCK-A receptors in mediating the postfeeding pancreatic response was also demonstrated. The participation of CCK-B/gastrin receptors in this regulation was not demonstrated.

Effect of exogenous insulin and glucagon on exocrine pancreatic secretion in rats in vivo

BACKGROUND

The physiological roles of the islet hormones insulin and glucagon in the control of exocrine pancreatic secretion is not clear. It is still unknown whether these hormones have a stimulatory or an inhibitory effect on the basal exocrine pancreatic secretion.

METHODS

Thirty anesthetized rats were stimulated with doses of insulin and glucagon administered by continuous intravenous infusion. Doses varying from physiological to supraphysiological were used. Different groups of 5 rats were given each of these doses. The volume of pancreatic juice and amylase, lipase and trypsin activity, as well as enzyme output, were measured 0, 20, 40, and 60 min after starting infusion. The insulin, glucagon, and glucose levels were determined in serum at 0, 10, 30, and 60 min.

RESULTS

In the insulin group, the secreted volume of pancreatic juice increases with the maximum dose. All insulin doses results in amylase and lipase decreased activity. When submaximum and maximum insulin doses are administered, the trypsin activity also decreases. In the glucagon group, the activity of lipase and trypsin decreases regardless the dose, whereas the amylase activity decreases with submaximum and supramaximum doses.

CONCLUSION

Both insulin and glucagon affect the basal exocrine pancreatic secretion in vivo when physiological doses are administered.

Pancreatic secretory responses in L-arginine-induced pancreatitis: comparison of diabetic and nondiabetic rats

The aim of this work was to study cholecystokinin-octapeptide (CCK-8)-stimulated pancreatic secretion after the induction of pancreatitis with L-arginine (ARG) in rats with or without streptozotocin (STZ) diabetes. One, 3, 7, and 14 days after pancreatitis induction, rats were surgically prepared with pancreatic duct and femoral vein cannulae under urethane anesthesia. Graded doses of CCK-8 ranging from 9 to 2,400 ng/kg/30 min were administered intravenously. In the control group, the step-wise increasing doses of CCK-8 resulted in a characteristic dose-response curve for the pancreatic volume, protein and amylase secretion (maximal volume, protein and amylase output at 600 ng/kg/30 min of CCK-8: 157 +/- 20.2 microl/30 min, 28.3 +/- 1.18 mg/30 min, and 3,750 +/- 92 IU/30 min, respectively). In rats with pancreatitis, the pancreatic volume (both basal and maximal) and amylase secretion were significantly elevated on day 1 versus the control group; then on days 3,7, and 14, the pancreatic secretory volume and amylase were progressively and significantly decreased versus the control group. However, the protein output was continuously decreased versus the control group on days 1, 3, 7, and 14. In diabetic rats, the maximal volume and protein and amylase output were all significantly decreased versus the control group throughout the experiment. In the diabetes + pancreatitis group, the maximal volume and protein and amylase output were all significantly increased versus the diabetes group on days 1, 3, 7, and 14. These results indicate that in the early phase of ARG-induced pancreatitis, the pancreatic secretion is characterized by increases in secretory volume and amylase, with a simultaneous decrease in protein output. Simultaneous diabetes seems to moderate the CCK-8-stimulated secretory changes in both the early and late phases after ARG-induced pancreatitis.

Exogenous CCK and gastrin stimulate pancreatic exocrine secretion via CCK-A but also via CCK-B/gastrin receptors in the calf

A predominance of the pancreatic cholecystokinin (CCK) receptor of the B/gastrin subtype (CCK-B/G) was reported in calves older than 1 month. Specific CCK-A and CCK-B/G receptor antagonists (SR 27897 and PD 135158, respectively) were used to identify the CCK receptor subtype involved in exogenous CCK- and gastrin-induced exocrine pancreatic responses. Conscious calves (2 months old) with catheterized pancreas, jugular vein and duodenum were used; the pancreatic juice was continuously reinfused. CCK (30 pmol kg-1 min-1, 40 min) evoked an increase in pancreatic juice flow and enzyme secretion, while the same dose of gastrin increased enzyme secretion alone. CCK-induced pancreatic secretion was abolished by SR 27897 (15 nmol kg-1 min-1, 55 min) and reduced by PD 135158 (0.15 nmol kg-1 min-1, 55 min). Gastrin-induced enzyme secretion was reduced by PD 135158 (50% to 90%) and to a lesser extent by SR 27897 (50% to 60%). These results demonstrate that CCK and gastrin in the physiological range stimulate pancreatic exocrine secretion in calves and that these effects are partly mediated by CCK-B/G receptors. Although CCK-A receptors are not predominantly expressed, they seem to play a major role in the response of pancreatic exocrine secretion to CCK.

COOH-terminally extended secretins are potent stimulants of pancreatic secretion

Posttranslational processing of preprosecretin generates several COOH-terminally extended forms of secretin and alpha-carboxyl amidated secretin. We used synthetic canine secretin analogs with COOH-terminal -amide, -Gly, or -Gly-Lys-Arg to examine the effects of COOH-terminal extensions of secretin on bioactivity and detection in RIA. Synthetic products were purified by reverse-phase and ion-exchange HPLC and characterized by reverse-phase isocratic HPLC and amino acid, sequence, and mass spectral analyses. Secretin and secretin-Gly were noted to coelute during reverse-phase HPLC. In RIA using eight different antisera raised against amidated secretin, COOH-terminally extended secretins had little or no cross-reactivity. Bioactivity was assessed by measuring pancreatic responses in anesthetized rats. Amidated canine and porcine secretins were equipotent. Secretin-Gly and secretin-Gly-Lys-Arg had potencies of 81 +/- 9% (P > 0.05) and 176 +/- 13% (P < 0.01), respectively, compared with amidated secretin, and the response to secretin-Gly-Lys-Arg lasted significantly longer. These data demonstrate that 1) amidated secretin and secretin-Gly are not separable under some chromatographic conditions, 2) current RIA may not detect bioactive COOH-terminally extended forms of secretin in tissue extracts or blood, and 3) the secretin receptor mediating stimulation of pancreatic secretion recognizes both amidated and COOH-terminally extended secretins.

Effects of intraduodenal administration of tarazepide on pancreatic secretion and duodenal EMG in neonatal calves

The influence of CCK-A receptor antagonism on pancreatic exocrine secretion and duodenal EMG, and the mechanism(s) involved in CCK-induced pancreatic secretion were studied in conscious calves. Seven 1-week-old calves were fitted with a pancreatic duct catheter, duodenal cannula and duodenal electrodes. Pancreatic exocrine secretion and duodenal EMG were studied following intraduodenal CCK-A receptor antagonist (Tarazepide), intravenous atropine, and intravenous or intraduodenal CCK-8 administrations. Tarazepide decreased duodenal electric activity, reduced interdigestive pancreatic secretion, especially protein; reduced cephalic and early postprandial (milk) induced secretion of bicarbonate and protein. Pancreatic protein secretion to intravenous CCK-8 was little affected by atropine, but was significantly reduced by Tarazepide+/-atropine; in contrast, protein secretion to intraduodenal CCK-8 was abolished by Tarazepide or atropine. We conclude that pre- and especially early postprandial pancreatic secretion are partly controlled via CCK-A (mainly mucosal) mediated mechanisms.

Glucagon-like peptide-1 inhibits gastropancreatic function by inhibiting central parasympathetic outflow

Glucagon-like peptide (GLP)-1 inhibits acid secretion and gastric emptying in humans, but the effect on acid secretion is lost after vagotomy. To elucidate the mechanism involved, we studied its effect on vagally stimulated gastropancreatic secretion and motility in urethan-anesthetized pigs with cut splanchnic nerves, in which insulin-induced hypoglycemia elicited a marked stimulation of gastropancreatic secretion and antral motility. In addition, we studied vagally stimulated motility and pancreatic secretion in isolated perfused preparations of the porcine antrum and pancreas. GLP-1 infusion (2 pmol. kg-1. min-1) strongly and significantly inhibited hypoglycemia-induced antral motility, gastric acid secretion, pancreatic bicarbonate and protein secretion, and pancreatic polypeptide (PP) secretion. GLP-1 (at 10(-10)-10(-8) mol/l) did not inhibit vagally induced antral motility, pancreatic exocrine secretion, or gastrin and PP secretion in isolated perfused antrum and pancreas. We conclude that the inhibitory effect of peripheral GLP-1 on upper gastrointestinal secretion and motility is exerted via interaction with centers in the brain or afferent neural pathways relaying to the vagal motor nuclei.

Canine pancreatic responses to intracolonic perfused nutrients

To study the effect intracolonic perfusion of nutrients has on exocrine pancreatic secretion, six dogs were prepared with gastric, duodenal, and cecal cannulas using a modified Thomas technique. In our study protocol, we collected pancreatic juice by selective ductal cannulation after having applied several types of intracolonic stimulation: perfusion of sodium chloride, tryptophan, rice starch + glucose, or sodium oleate. All these solutions were applied together with a background dose of intravenous secretin. Our results showed a significant increase in the volume of pancreatic juice and bicarbonate output after intracolonic perfusion of sodium oleate. Other perfusions did not change these parameters. Protein output did not change in any of the cases. It seems that the ascending colon plays a regulating role in pancreatic secretion; in some conditions the colon could increase exocrine pancreatic function.

Effects of loxiglumide on pancreatic exocrine secretion stimulated by meal in conscious dogs

The effects of loxiglumide (CAS 107097-80-3, CR 1505), a novel cholecystokinin-A(CCK-A) receptor antagonist, on pancreatic exocrine secretion stimulated by meal were examined in conscious dogs with chronic pancreatic fistula. Pancreatic exocrine secretion was stimulated by intraduodenal infusion of a liquid test meal and postprandial plasma CCK levels were apparently elevated. Loxiglumide inhibited the meal-stimulated outputs of pancreatic protein, amylase and bicarbonate at an intravenous dose of 10 mg/kg/h (p < 0.05). However, loxiglumide did not show apparent inhibition of pancreatic juice volume and trypsin output. These results show that the selective CCK-A antagonist loxiglumide may inhibit the increase of pancreatic exocrine secretion based on selective blockade of receptor binding of CCK endogenously induced by meal in dogs.

Inhibitory effect of central dopamine on basal pancreatic secretion in conscious rats

We examined the role and the peripheral mechanism of action of central dopamine on basal pancreatic exocrine secretion in conscious rats. Rats were fitted with bile and pancreatic catheters to collect bile and pancreatic juice separately and also with a left lateral brain ventricle and external jugular vein catheters. After 90-min basal collection, the D1- and D2-receptor antagonists (Sch-23390 and eticlopride, respectively) and dopamine were administered into the lateral brain ventricle. Sch-23390 (30, 100, and 300 nmol/rat), but not eticlopride (300 nmol/rat), stimulated pancreatic fluid and protein secretion. Dopamine (30, 100, and 300 nmol/rat) inhibited pancreatic secretion lose dependently. Pretreatment with Sch-23390 prevented the inhibitory effect of dopamine. Intravenously injected Sch-23390 or dopamine had no effect on pancreatic secretion. The inhibitory effect of dopamine was blocked by bretylium, an inhibitor of norepinephrine release, and phentolamine, an alpha-blocker, but not by vagotomy. The beta-antagonist propranolol alone significantly inhibited basal pancreatic secretion, and dopamine did not modify the inhibitory effect of propranolol. The proton pump inhibitor omeprazole partially but not completely reduced the inhibition by dopamine. These results suggest that central dopamine inhibits pancreatic exocrine secretion via D1-like receptors and that the inhibitory effect is mediated via sympathetic nerves, especially alpha-adrenoceptors.

Pure pancreatic juice from patients with chronic pancreatitis has an impaired antibacterial activity

CONCLUSION

These data show that pure pancreatic juice of AICP patients has a markedly defective antibacterial activity. This finding might be of potential clinical interest in the understanding of the pathophysiology of the disease.

BACKGROUND

The aim of the present study was to test the antibacterial activity of pure pancreatic juice in patients with chronic pancreatitis.

METHODS

The study group consisted of ten patients with ethanol-induced chronic pancreatitis (AICP) and seven control patients free of pancreatic disease. All subjects had recently undergone a secretin-pancreozymin pancreatic function test. After an overnight fast, through a side-viewing endoscope, selective pancreatic duct cannulation was performed. After secretin stimulation, pure pancreatic juice was obtained. Three fractions of different molecular weights were separated. Samples were incubated with 1-mL suspension of 10(5) Escherichia coli ATCC 25,922, and log10 of colony-forming units were counted. Experiments were repeated by grading pancreatic juice concentration, pH of the medium, and inoculum size.

RESULTS

No significant change of pH of pure pancreatic juice appeared between AICP and controls. Starting from 6-h observation, pure pancreatic juice of AICP patients showed a significant bacterial colonization vs controls (p < 0.01). A direct correlation appeared between bacterial colonization and either pH and dilution of pancreatic juice (p < 0.001). Antibacterial activity was independent of inoculum size, enzymatic activation or inhibition, and heat treatment. The fraction with 1000-10,000 molecular weight was the one endowed with antibacterial activity.

Effects of a panel of dietary lectins on cholecystokinin release in rats

We previously showed that soybean lectin (SBL) releases cholecystokinin (CCK) and have now asked whether other dietary lectins have this effect and if extracellular calcium is involved. Lectins and vehicle were first infused into the duodenum of anesthetized rats. The CCK response to vehicle was 3.1 +/- 0.6 pmol/l (P < 0.05 vs. basal). SBL and peanut lectin (PNL) (84 microg/ml) significantly increased plasma CCK concentrations from 2.0 +/- 0.4 pmol/l to a maximum of 8.4 +/- 0.5 pmol/l (P < 0.01 vs. vehicle, mean +/- SE) and from 1.9 +/- 0.5 to 7.0 +/- 0.6 pmol/l (P < 0.05 vs. vehicle, mean +/- SE), respectively. Wheat germ lectin (WGL) (840 microg) also increased plasma CCK levels from 1.5 +/- 0.3 pmol/l to a maximum of 9.7 +/- 1.3 pmol/l (P < 0.05 vs. vehicle, mean +/- SE). Corresponding increases in pancreatic protein output occurred. Broad bean lectin (BBL) had no effect on either parameter. Dose-dependent responses were seen with SBL, PNL, and WGL (1, 10, and 100 microg/ml) in perifused rat intestinal cells. These responses were abolished in calcium-free medium and in the presence of the competing sugars of the lectins. Therefore, SBL, PNL, and WGL, which bind to motifs including N-acetyl-D-galactosamine, galactose, and N-acetylglucosamine, respectively, released CCK, but BBL, which binds to mannose and glucose, did not. Ingestion of lectins may have major CCK-mediated effects on gastrointestinal function and growth.

Stimulative effects of saponin from kikyo-to, a Japanese herbal medicine, on pancreatic exocrine secretion of conscious rats

Our previous report stated that kikyo-to, a Japanese herbal medicine, consisting of the roots of Platycodon grandiflorum and Glycyrrhiza sp., stimulates the pancreatic exocrine secretion of conscious rats. The present study focused on the effective components of kikyo-to and the mechanism of stimuli to pancreatic secretion of rats. When 10 to 100 mg of platycodin D, a saponin from the root of Platycodon grandiflorum, was intragastrically administered, the pancreatic secretion of rats was stimulated. At the same time, the plasma CCK concentration increased. On the other hand, the stimulative effects of glycyrrhizin, a saponin from the root of Glycyrrhiza sp. were weak compared to platycodin D. The effects of 10 mg/kg of platycodin D on pancreatic secretion were inhibited by loxiglumide (50 mg/kg, i.g.), a CCK receptor antagonist. In contrast, the suppressive effect of atropine (300 micrograms/kg/h, i.v.) on pancreatic secretion was reduced by administering 10 mg/kg of platycodin D. In addition, up to 1 mM of platycodin D did not inhibit the trypsin activities in vitro. In conclusion, kikyo-to serves to stimulate pancreatic exocrine secretion mainly because platycodin D causes gastrointestinal hormones, particularly, CCK to be released from the duodenum.

An amino-terminal fragment of LCRF, LCRF-(1-35), has the same activity as the natural peptide

A cholecystokinin (CCK)-releasing peptide, luminal CCK-releasing factor (LCRF), has been purified from rat jejunal secretion. Amino acid analysis and mass spectral analysis showed that the purified peptide is composed of 70-75 amino acid residues and has a mass of 8,136 Da. Microsequence analysis of LCRF yielded an amino acid sequence for the amino-terminal 41 residues. To determine the biologically active region of the molecule, a peptide was synthesized consisting of the amino-terminal 35 amino acids of LCRF. In this study, intraduodenal infusion of LCRF-(1-35) significantly stimulated pancreatic secretion in conscious rats. The dose-response curves to LCRF-(1-35) and to monitor peptide were similar and biphasic, with higher doses producing submaximal pancreatic secretory responses. The CCK-A receptor antagonist MK-329 abolished the pancreatic secretory response to intraduodenally infused LCRF-(1-35). These results demonstrate that LCRF biological activity is contained within the amino-terminal 35-amino acid portion of LCRF, and this fragment may be useful for investigating the role of LCRF in gastrointestinal function.

Electrophoretic separation of proteolytic enzymes in pancreatic juice collected with the pouch or catheter method

CONCLUSION

The results of this study demonstrated that proteolytic enzymes in pancreatic juice from pigs prepared with the pouch method (PM) were nearly fully active or were fully active. When activation with enterokinase was carried out further inactivation and/or breakdown occurred for chymotrypsin C and cathodal trypsin. In addition, some inactivation and/or breakdown of proteolytic enzymes in pancreatic juice occurred during collection of pancreatic juice from PM pigs.

METHODS

Samples of pancreatic juice were collected from growing pigs using either the PM or the catheter method (CM). An isolated pouch was prepared where the pancreatic duct enters the duodenum, and three pigs were fitted with a pancreatic pouch re-entrant cannula. Three different pigs had a catheter surgically inserted into the pancreatic duct. Pooled 8-h samples of pancreatic juice were analyzed before and after activation with enterokinase. Chymotrypsin, trypsin, and elastase activities were identified in pancreatic juice after separation by electrophoresis in 1% agarose gels at pH 8.6 using N-acetyl-DL-phenylalanine-beta-naphthyl ester (Ac-Phe-beta ne) as a substrate.

RESULTS

This qualitative enzyme assay indicated that a considerable amount of chymotrypsin C, anodal trypsin, chymotrypsins A and B, elastase II, and cathodal trypsin were present in samples of nonactivated pancreatic juice from PM pigs. In contrast, the only active enzymes identified in pancreatic juice from CM pigs were very small amounts of chymotrypsin A and elastase II. The amounts of chymotrypsin C and cathodal trypsin were lower in activated than in nonactivated pancreatic juice from PM pigs. However, there were increases in the amounts of the other enzymes when pancreatic juice from PM pigs was activated. As expected, the activation of pancreatic juice from CM pigs resulted in the measurement of very high amounts of all the proteolytic enzymes. The amounts of anodal trypsin, chymotrypsins A and B, and elastase II were higher in activated pancreatic juice from CM pigs than from PM pigs.

An investigation into the relative merits of pituitary adenylate cyclase-activating polypeptide (PACAP-27) and vasoactive intestinal polypeptide as vagal neuro-transmitters in exocrine pancreas of rats

Pancreatic exocrine secretions were collected over 15 min periods and analysed in terms of weight of juice, total HCO3- and total protein in anaesthetized and pithed rats. Pituitary adenylate cyclase-activating polypeptide (PACAP) (i.v.) evoked a serous HCO3- secretion which contained relatively little protein, together with a marked vasodepressor action. The latter was still maximal at lower doses of PACAP, which evoked diminished pancreatic secretions. The effects of PACAP were similar to those evoked by the same dose of VIP and by cervical vagal stimulation, while secretion evoked a much larger secretion of fluid and HCO3-. The time courses of the PACAP-evoked secretions were significantly delayed compared with those of VIP. In the pithed rat, PACAP caused the same level of pancreatic secretions as in the anaesthetized rat, though this was now accompanied by a substantial pressor response which was blocked by phentolamine or prazosin, indicating that it was alpha 1-adrenoceptor mediated. VIP caused a depressor response in the pithed rat, as well as the same level of pancreatic secretions as in the anaesthetized rat. The putative VIP antagonist [Lys1,Pro25,Arg3,4,Tyr6]-VIP (abbreviated as VIPi) caused a selective and significant reduction in the HCO3- secretion evoked by VIP and blocked the vasodepressor response caused by VIP. By contrast, VIPi did not antagonize either the secretory or vasodepressor actions of PACAP. Unilateral electrical stimulation of the cervical vagus nerve evoked significant increases in the weight of juice, total protein and total HCO3- secreted. When preceded by injection of VIPi, vagally evoked secretions were unchanged in terms of weight of juice and total protein but had a significantly reduced HCO3- content. These results are consistent with the release of VIP, though not PACAP, as a vagal neurotransmitter in the exocrine pancreas.

Effects of telenzepine and L-364,718 on canine pancreatic secretion before and after vagotomy

In six conscious dogs we compared the action of the M1-receptor antagonist telenzepine (20.25-81.0 nmol.kg-1.h-1), the cholecystokinin (CCK) antagonist L-364,718 (0.025-0.1 mg.kg-1.h-1), and combinations of both on the pancreatic secretory response to intraduodenal tryptophan, given against a secretin background before and after truncal vagotomy. Before vagotomy, the higher doses of telenzepine and of L-364,718 significantly (P < 0.05) decreased the protein response to tryptophan by up to 97%. After vagotomy, all doses of L-364,718 abolished the protein response, whereas telenzepine had no further effect. Before and after vagotomy, all combinations abolished the protein response. The plasma CCK-like immunoreactivity basally, during secretin, and in response to tryptophan was not altered by vagotomy, telenzepine, and/or L-364,718. These findings indicate that in dogs 1) potentiation exists between M1 receptors and CCK for stimulation of the pancreatic enzyme response to intraduodenal tryptophan, 2) the cholinergic fibers of the enteropancreatic reflex activated by tryptophan run within the vagus nerves and end at least in part on M1 receptors, 3) CCK acts in part independently of the vagal nerves, and 4) the CCK release by intestinal tryptophan is not influenced by vagotomy, telenzepine, and/or L-364,718.

Intraductal secretin test is as useful as duodenal secretin test in assessing exocrine pancreatic function

We assessed the clinical usefulness of the intraductal secretin test in order to ascertain whether it can substitute for the conventional duodenal secretin test. Duodenal juice was obtained with a triple-lumen tube and pure pancreatic juice was obtained by retrograde cannulation of the main pancreatic duct using a duodenofiberscope. Pancreatic secretion was stimulated by a bolus intravenous injection of secretin (100 units). The two tests showed comparable interindividual coefficients of variation, significantly good correlations, and comparable diagnostic efficiencies. The intraductal secretin test showed no less reproducibility than that of the duodenal secretin test as reported in the literature. In the intraductal secretin test, secretory volume, peak flow rate, bicarbonate output, and lipase output yielded the best diagnostic efficiency, followed by amylase output and maximal bicarbonate concentration. In the intraductal secretin test, a 10-min collection provided as much information as a 20-min collection. We conclude, therefore, that the 10-min intraductal secretin test is as useful as the conventional duodenal secretin test in assessing exocrine pancreatic function and that the most discriminatory parameters are secretory volume, bicarbonate output, and amylase (or lipase) output.

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

BACKGROUND

Nitric oxide (NO) is an unstable vasodilator formed by NO synthetase (NOS) from L-arginine (L-Arg) in various cells but its role in the control of pancreatic secretion in humans has not been examined.

AIMS

This study was designed to determine the role of endogenous NO in the control of exocrine and endocrine pancreas using NOS inhibitor, NG-monomethyl-L-Arg (L-NMMA).

METHODS

Pancreatic secretion was stimulated by intravenous infusion of secretin (80 pmol/kg/h) plus caerulein (50 pmol/kg/h) and duodenal content was aspirated by gastroduodenal tube. Two series of tests with secretagogue infusion were performed, one, with addition of graded doses of L-NMMA and, another, with addition of a constant dose of L-Arg alone followed by L-NMMA alone and finally by a combination of L-Arg and L-NMMA.

RESULTS

Addition of L-NMMA in graded doses (2-8 mumol/kg/h) reduced dose dependently the secretin-caerulein stimulated pancreatic enzyme secretion without alterations in the volume flow and bicarbonate outputs. The addition of L-Arg to L-NMMA reversed the inhibitory action of L-NMMA on protein enzyme response to secretin-caerulein in these subjects. Secretin-caerulein infusion caused significant increase in plasma insulin and pancreatic polypeptide levels but without changes in plasma glucagon or somatostatin levels. L-NMMA alone resulted in a significant fall in plasma insulin and pancreatic polypeptide levels, while L-Arg added to pancreatic secretagogue infusion caused a significant increase of plasma insulin and pancreatic polypeptide levels above those attained with secretagogues alone. After the addition of L-Arg to L-NMMA, both plasma insulin and pancreatic polypeptide levels rose significantly above the levels observed with L-NMMA plus secretin-CCK stimulation.

CONCLUSION

This study provides evidence that the suppression of NOS reduces pancreatic enzyme secretion and the plasma insulin and pancreatic polypeptide levels suggesting that endogenous NO affects both exocrine and endocrine pancreatic secretion in humans.

Pancreatic exocrine function during acute exacerbation in WBN/Kob rats with spontaneous chronic pancreatitis

CONCLUSION

Pancreatic exocrine hypofunction is markedly deteriorated during acute exacerbation in a rat model with chronic pancreatitis.

BACKGROUND

Little is known about pancreatic exocrine function during acute exacerbation in patients with chronic pancreatitis. We investigated changes in pancreatic exocrine function after inducing acute pancreatitis in an animal model of spontaneous chronic pancreatitis.

METHODS

WBN/Kob rats with chronic pancreatitis sequentially underwent pancreatic exocrine function test 1-6 d after surgical preparation with external pancreatic fistula. We induced acute pancreatitis in another WBN/Kob rats by i.v. administration of cerulein at a rate of 10 micrograms/kg/h for 4 h 4 d after surgical preparation. Pancreatic exocrine function test was undertaken in a conscious state 1 d before and after cerulein administration.

RESULTS

In WBN/Kob rats not given cerulein, pancreatic exocrine function remained almost constant at 3-6 d after surgery. Marked hyperamylasemia developed immediately after cerulein administration. After its administration, the pancreas microscopically showed prominent interstitial edema and intracellular vacuolization of acinar cells in addition to the finding of pre-existing chronic pancreatitis. Basal and cholecystokinin-stimulated flow rate, bicarbonate output, and protein output, which were substantially impaired 1 d before cerulein administration, were further reduced 1 d after its administration.

Plasma immunoreactive cationic trypsin(ogen) pattern in reserpinized rat model of cystic fibrosis. Resemblance to humans

Plasma immunoreactive cationic trypsin (ogen) is elevated in cystic fibrosis during early infancy, before exocrine pancreatic insufficiency is fully developed. The recently developed cystic fibrosis mouse model carrying a mutated gene presents only minor pathologic findings in the pancreas. However, the reserpinized rat model shows cystic fibrosis-like defects in various exocrine glands, including the exocrine pancreas. Plasma immunoreactive cationic trypsin (ogen) has not been studied yet in this model. The present study explored the plasma immunoreactive cationic trypsin (ogen) pattern and possible mechanisms in this rat model. Plasma immunoreactive cationic trypsin (ogen) (RIA), pancreatic juice volume, protein, and trypsin, and pancreas weight were determined in rats treated with reserpine (0.5 mg/kg/day subcutaneously) for four or seven days, following cerulein stimulation (5 micrograms/kg/dose intraperitoneally), versus pair-fed controls. The first of four consecutive 30 min periods revealed peak values in all parameters. Four-day reserpine-treated rats demonstrated significantly higher plasma immunoreactive cationic trypsin (ogen) levels (167.3 +/- 12.8 vs 88.9 +/- 6.1 ng/ml; P < 0.0001) with similar values of pancreatic juice trypsin (8.2 +/- 2.4 vs 6.6 +/- 1.8 units/mg protein; P = NS) and volume (5.6 +/- 1.3 vs 4.2 +/- 1.6 mg/min/g pancreas; P = NS), compared to controls. Rats treated with reserpine for seven days revealed significantly lower values of plasma immunoreactive cationic trypsin (ogen) (39.2 +/- 8.4 vs 66.8 +/- 4.9 ng/ml; P < 0.001), pancreatic juice trypsin (1.9 +/- 0.3 vs 3.2 +/- 0.9 units/mg protein; P < 0.001) and volume (1.6 +/- 0.7 vs 3.1 +/- 0.6 mg/min/g pancreas; P < 0.001) compared to controls. We conclude that the reserpinized rat model resembles human cystic fibrosis as to elevated plasma immunoreactive cationic trypsin (ogen) before exocrine pancreatic insufficiency is fully developed. Since exocrine pancreatic volume secretion is intact at this stage, the mechanism of elevated plasma immunoreactive cationic trypsin is probably not due to ductular obstruction. We suggest that this model be studied further in order to investigate other possible mechanisms.

Cholecystokinin-8 and vasoactive intestinal polypeptide stimulate exocrine pancreatic secretion via duodenally mediated mechanisms in the conscious pig

The effects of local and peripheral administration of cholecystokinin-8 (CCK-8) and vasoactive intestinal polypeptide (VIP) on basal pancreatic secretion were investigated in conscious pigs. Five pigs (20 +/- 2 kg, mean +/- S.E.M.) were chronically fitted with a T-shaped cannula in the duodenum, and catheters in the pancreatic duct, jugular vein, and right gastroepiploic artery. The arterial catheter was inserted against the bloodstream with its tip opposite the duodenal branch(es) of the right gastroepiploic artery, so that all injected peptides would reach the duodenal arterial circulation excluding the pancreas. Pancreatic secretion during basal conditions (i.e. after an overnight fast) exhibited a characteristic cyclic pattern (cycle duration, 70 +/- 4.2 min). Secretion volume oscillated between 0.2 +/- 0.04 and 4.0 +/- 0.9 ml kg-1 h-1 (P < 0.001), trypsin output between 9.6 +/- 1.9 and 29.1 +/- 4.1 U kg-1 h-1 (P < 0.001) and protein output between 0.36 +/- 0.08 and 9.2 +/- 1.7 mg kg-1 h-1 (P < 0.001). Infusion into the jugular vein for 1 min, during the trough of pancreatic secretion, of either CCK-8 (15 pmol kg-1 min-1) or VIP (7 pmol kg-1 min-1) did not stimulate pancreatic secretion. However, local infusion of an identical dose of CCK-8 or VIP into the duodenal arterial circulation increased the volume, protein output and trypsin output of the pancreatic juice (P < 0.05 to < 0.001). These results indicate that CCK-8 and VIP can stimulate the exocrine pancreas by a duodenally mediated mechanism.

Purification and characterization of a luminal cholecystokinin-releasing factor from rat intestinal secretion

Cholecystokinin (CCK) secretion in rats and humans is inhibited by pancreatic proteases and bile acids in the intestine. It has been hypothesized that the inhibition of CCK release caused by pancreatic proteases is due to proteolytic inactivation of a CCK-releasing peptide present in intestinal secretion. To purify the putative luminal CCK-releasing factor (LCRF), intestinal secretions were collected by perfusing a modified Thiry-Vella fistula of jejunum in conscious rats. From these secretions, the peptide was concentrated by ultrafiltration followed by low-pressure reverse-phase chromatography and purified by reverse-phase high-pressure liquid chromatography. Purity was confirmed by high-performance capillary electrophoresis. Fractions were assayed for CCK-releasing activity by their ability to stimulate pancreatic protein secretion when infused into the proximal small intestine of conscious rats. Partially purified fractions strongly stimulated both pancreatic secretion and CCK release while CCK receptor blockade abolished the pancreatic response. Amino acid analysis and mass spectral analysis showed that the purified peptide is composed of 70-75 amino acid residues and has a mass of 8136 Da. Microsequence analysis of LCRF yielded an amino acid sequence for 41 residues as follows: STFWAYQPDGDNDPTDYQKYEHTSSPSQLLAPGDYPCVIEV. When infused intraduodenally, the purified peptide stimulated pancreatic protein and fluid secretion in a dose-related manner in conscious rats and significantly elevated plasma CCK levels. Immunoaffinity chromatography using antisera raised to synthetic LCRF-(1-6) abolished the CCK releasing activity of intestinal secretions. These studies demonstrate, to our knowledge, the first chemical characterization of a luminally secreted enteric peptide functioning as an intraluminal regulator of intestinal hormone release.

Duration of anti-cholecystokinin (CCK) action on the rat exocrine pancreas of new CCK receptor antagonist FK480 administered orally

We assessed the duration of the anti-cholecystokinin (CCK) action of FK480, a new non-peptide CCK-A receptor antagonist developed in Japan, in an in vivo study in rats, comparing it with CR 1505. Pancreatic exocrine secretion stimulated by intravenous infusion of CCK-8 (0.06 microgram/kg per h) was measured at intervals of 0-24 h after the oral administration of FK480 (1.5 mg/kg) and CR 1505 (30 mg/kg). FK480 significantly inhibited both CCK-stimulated pancreatic juice volume flow and amylase output 0, 4, 8, and 12 h after oral administration, whereas the inhibitory effect of CR 1505 had completely disappeared by 8 h after oral administration. It was concluded that orally administered FK480 has a prolonged anti-CCK action.