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Background: Octreotide is known to decrease the rate of postoperative complication after pancreatic resection by diminishing exocrine function of the pancreas. The aim of this study was to evaluate the effect of octreotide in decreasing exocrine excretion of pancreas and preventing pancreatic fistula., Materials and Methods: Prospective randomized trial was conducted involving 59 patients undergoing pancreaticoduodenectomy for either malignant or benign tumor, 29 patients were randomized to receive octreotide; 30 patients allotted to placebo. All pancreaticojejunal anastomosis was performed with external stent of negative-pressured drainage and the amount of pancreatic juice through the external stent was measured until postoperative 7th day. Pancreatic fistula was recorded., Results: There were no differences in demographics, pancreatic texture and pancreatic duct diameter between the octreotide and placebo group. The median output of pancreatic juice was not significantly different between both groups during 7 days after surgery. When the patients were stratified according to the diameter of pancreatic duct (duct ≤5 mm, > 5 mm), there were no significant differences in daily amount of pancreatic juice, however, when stratified according to pancreatic texture, median output of pancreatic juice was significantly lower in patients with hard pancreas compared with those with soft pancreas from 5 day to 7 day after surgery (p < 0.05). No significant differences in pancreatic fistula and postoperative complications were found between the octreotide and placebo groups., Conclusions: Prophylactic octreotide is not effective to inhibit the exocrine secretion of the remnant pancreas and does not decrease the incidence of pancreatic fistula after pancreaticoduodenectomy., (Copyright © 2018. Published by Elsevier Taiwan LLC.)

Aims: The prognosis of patients with pancreatic cancer has remained virtually unchanged with a high mortality rate compared to other types of cancers. An earlier detection would provide a time window of opportunity for treatment and prevention of deaths. In the present study we investigated extracellular vesicle (EV)-associated potential biomarkers for pancreatic cancer by directly assessing EV size-based subpopulations in pancreatic juice samples of patients with chronic pancreatitis or pancreatic cancer. In addition, we also studied blood plasma and pancreatic cancer cell line-derived EVs., Methods: Comparative proteomic analysis was performed of 102 EV preparations from human pancreatic juices, blood, and pancreatic cancer cell lines Capan-1 and MIA PaCa-2. EV preparations were also characterized by electron microscopy, tunable resistive pulse sensing, and flow cytometry., Results: Here we describe the presence of EVs in human pancreatic juice samples. Pancreatic juice EV-associated proteins that we identified as possible candidate markers for pancreatic cancer included mucins, such as MUC1, MUC4, MUC5AC, MUC6 and MUC16, CFTR, and MDR1 proteins. These candidate biomarkers could also be detected by flow cytometry in EVs found in pancreatic juice and those secreted by pancreatic cancer cell lines., Conclusions: Together our data show that detection and characterization of EVs directly in pancreatic juice is feasible and may prove to be a valuable source of potential biomarkers of pancreatic cancer., (Copyright © 2018 The Authors. Published by Elsevier Inc. All rights reserved.)

The neuronal pentraxin II (NPTX2) gene is methylated in over 90% primary pancreatic cancer tissues but rarely in normal pancreatic ductal epithelia. Here, the authors investigated the utility of methylated NPTX2 as a diagnostic marker for pancreatic cancer in pure pancreatic juice samples of patients with benign and malignant pancreatic diseases, including pancreatic cancer, intraductal papillary mucinous neoplasm or chronic pancreatitis using methylation-specific polymerase chain reaction (MSP) and quantitative MSP. MSP assays revealed that the incidence of aberrant NPTX methylation in pure pancreatic juice samples was 64.5% (20 of 31) in patients with pancreatic cancer, 70.0% (7 of 10) in patients with malignant intraductal papillary mucinous neoplasm, 33.3% (2 of 6) in patients with benign intraductal papillary mucinous neoplasm and 21.7% (5 of 23) in patients with chronic pancreatitis. NPTX2 hypermethylation in patients with chronic pancreatitis was significantly lower than that of pancreatic cancer (P < 0.01) or patients with intraductal papillary mucinous neoplasm (P < 0.05). At a cutoff value of 1.39 for quantitative MSP, the incidence of aberrant NPTX2 methylation was 61.3% (19 of 31) in patients with pancreatic cancer, 50.0% (5 of 10) in patients with malignant intraductal papillary mucinous neoplasm, 0% in patients with benign intraductal papillary mucinous neoplasm and 8.7% (2 of 23) in patients with chronic pancreatitis. There was a significant difference in NPTX2 methylation between pancreatic cancer and chronic pancreatitis (P < 0.01). Our findings indicate that detection of aberrant methylation of NPTX2 in pure pancreatic juice samples could be useful as a molecular marker to discriminate between patients with malignant and benign disease of the pancreas.

Pancreatic acinar cells secrete fluid and digestive enzymes. Both types of secretion are activated by a rise in intracellular calcium but how the stimulus-secretion cascade actually regulates secretory output is not well understood. It has long been known that the calcium response of acinar cells to physiological stimulation is complex. Dependent on the type and concentration of agonist, it consists of either local or global calcium increases as well as spreading waves of calcium across the cell. In the past it has been speculated that these different calcium signals drive different secretory responses. Now, recent employment of two-photon microscopy has enabled the simultaneous recording of both enzyme secretion and calcium signals and is beginning to resolve this issue. The data shows that local calcium responses exclusively drive fluid secretion. Where-as, global calcium responses drive both fluid and enzyme secretion. This differential control of secretory output is likely central to controlling the physiological responses of pancreatic acinar cells., (Copyright 2010 Elsevier Ltd. All rights reserved.)

Although pancreaticoduodenectomy has become a safe and effective procedure for benign and malignant pancreatic diseases in recent years, leakage of pancreaticoenteric anastomosis still remains a major cause of morbidity and even mortality. Various methods have been used to prevent pancreatic fistula with either pharmacologic or technical approaches. Based on meta-analysis of results from European and American trials, prophylactic use of octreotide to inhibit pancreatic secretion cannot be recommended for routine use in pancreaticoduodenectomy. Further randomized trials are required to clarify the role of selective use of octreotide in patients at high risk for pancreatic leakage. Technical improvement by surgeons is probably the most important approach to reduce pancreatic anastomotic leakage rate. Various technical modifications for pancreaticoenteric anastomosis have been suggested; some have been tested in randomized controlled trials, but data from randomized trials are generally scarce. Use of PG instead of PJ anastomosis, internal stenting of PJ anastomosis, pancreatic duct occlusion, and fibrin glue have not been shown to be effective in reducing pancreatic leakage rate after pancreaticoduodenectomy. One randomized trial recently showed significant reduction of pancreatic leakage rate using an external diverting stent after PJ anastomosis, and another randomized trial showed significant reduction in PJ anastomosis leakage using the binding PJ anastomosis technique. Nonetheless, further high-quality randomized controlled trials are needed to evaluate the benefit of these technical modifications in decreasing the pancreatic leakage rate after pancreaticoduodenectomy.

Pancreatic duct cells secrete the HCO(3)(-) ions found in pancreatic juice. While the regulatory pathways that stimulate pancreatic ductal HCO(3)(-) secretion are well described, little is known about inhibitory pathways, apart from the fact that they exist. Nevertheless, such inhibitory pathways may be physiologically important in terms of limiting the hydrostatic pressure within the lumen of the duct, and in terms switching off pancreatic secretion after a meal. Methionine encephalin, insulin, somatostatin, peptide YY, substance P, basolaterally applied adenosine triphosphate, arginine vasopressin, 5-hydroxytryptamine and epidermal growth factor have all been shown to inhibit fluid and/or HCO(3)(-) secretion from pancreatic ducts. Importantly, most of these inhibitors have been shown to reduce secretion in isolated pancreatic ducts, so they must act directly on the ductal epithelium. This brief review provides an overview of our current knowledge of the inhibitors, and inhibitory pathways of pancreatic ductal secretion. SIGNALLING NETWORK FACTS: Methionine encephalin, insulin, somatostatin, peptide YY, substance P, basolaterally applied adenosine triphosphate, arginine vasopressin, 5-hydroxytryptamine and epidermal growth factor have all been shown to inhibit fluid and/or HCO(3)(-) secretion from pancreatic ducts. The inhibition of pancreatic secretion can be mediated by indirect (decreased cholinergic or increased adrenergic stimulation, decreased release of stimulatory hormones) and direct (inhibitory hormone or neurotransmitter acting on the duct cells) mechanisms.

Background: Oxygen-free radicalscan play a role in the development of chronic pancreatitis, altering the redox state with damage of cell constituents and decrease in antioxidant defences., Aims: To measure levels of lipoperoxidation products, conjugated dienes and lipid hydroperoxides, in pure pancreatic juice and serum of chronic pancreatitis patients and compare them to that in controls. To investigate a possible correlation with serum indexes of pancreatic inflammation (amylase and lipase)., Patients: Pancreatic juice was collected during ERCP, after secretin stimulation, in 20 patients with chronic pancreatitis and 11 controls with biliary diseases., Methods: Lipid hydroperoxide levels were determined with FOX2 method and measured as absorbance at 560 nm. Conjugated diene levels were measured using second-derivative spectroscopy., Results: No substantial difference was present in serum levels of lipid hydroperoxides, conjugated dienes (in both isomeric forms) and isomer-ratio values between those of patients with chronic pancreatitis and controls. In pancreatic juice, there was a significant increase in lipid hydroperoxides and conjugated dienes levels (especially trans-trans isomers) in chronic pancreatitis patients compared with controls, with a decrease in cis-trans isomers and a significant difference in isomer-ratio values., Conclusions: Increased levels of lipid hydroperoxides and conjugated dienes in the pancreatic juice of chronic pancreatitis patients is indicative of an enhanced lipoperoxidation and antioxidants consumption in pancreatic tissue, confirmed by the decreased isomer-ratio values as an indirect index of decreased antioxidant capacity. The lack of significant difference in conjugated diene and lipid hydroperoxide levels in the serum of chronic pancreatitis patients versus that of controls suggests an oxidative stress limited to pancreatic tissue and indicative of an organ-specific pathology, confirmed by the parallel behaviour of oxidative parameters (lipid hydroperoxides and conjugated dienes) and indexes of pancreatic inflammation (amylase and lipase).

Pancreatic exocrine secretion is known to be facilitated by gastric antral distension via long- and short-route reflexes. In this study, we studied the effects of gastric distension on intra-pancreatic nerve discharges and blood insulin level as well as pancreatic exocrine secretion. Mongrel dogs were anesthetized with ketamine and thiopental, and immediately decerebrated. This study consisted of two series of experiments. In the first series, efferent discharges in an intra-pancreatic nerve branch were recorded, and its responses to antral distension were analyzed. In the second series, effects of antral distension on pancreatic exocrine secretion and blood insulin level were observed before and after vagotomy in splanchnicectomized dogs. Efferent discharges in a pancreatic nerve branch were increased by antral distension. Neither vagotomy nor splanchnicectomy produced obvious changes in the neural response. In splanchnicectomized dogs, antral distension elevated blood insulin level and increased pancreatic exocrine secretion. After subsequent vagotomy, these effects were reduced, but the increases were still greater than 50%. These results indicate that the antro-pancreatic short-route reflex plays a significant role in exocrine secretion, and also suggest that insulin release is increased by antral distension independent of blood glucose level.

The ability to control carbohydrate digestion is useful in the treatment of diabetes mellitus and obesity. In the present study, we examined whether recently developed 4(2)-O-beta-D-galactosyl maltobionolactone (LG2O) having anti-amylase activity is able to control postprandial blood glucose concentration in mice. In addition, we tried to determine how LG2O regulates carbohydrate delivery in the gut lumen by conducting in vivo and in vitro studies. Male non-diabetic ddY mice and KK-A(y) mice, a spontaneously diabetic strain, had free access to a carbohydrate rich diet supplemented with LG2O (3 or 10 g/kg) for 0.5 hr, and blood glucose concentration was measured. LG2O suppressed any steep increase in postprandial blood glucose concentration in both ddY and KK-A(y) mice. Corresponding to the blood glucose response, LG2O also markedly suppressed any increase in postprandial plasma insulin concentration. After ingestion of the diet, LG2O produced a 1.5-3.5 fold increase in the gut contents and reducible sugar content in the small intestine but not in the stomach. Although alpha-amylase activity in the stomach was much lower compared with the activity in the small intestine, LG2O still strongly inhibited alpha-amylase activity in the stomach. In contrast, LG2O had little or no influence on alpha-amylase activity in the proximal intestine. From the in vitro carbohydrate digestion stimulation, LG2O at 7.5 mM decreased glucose production by 75% for dextrin, 25% for alpha-starch and 60% for raw starch. In conclusion, administration of LG2O inhibits carbohydrate digestion in the gut, and produces significant improvements in both blood glucose and insulin response following ingestion as part of the diet, and this evidence provides support for its therapeutic potential in treating diabetes mellitus and obesity.

An experiment was conducted to study the effect of feeding diets containing fat sources with different fatty acid composition (fish oil, coconut oil or lard, 10 g/100 g diet) on exocrine pancreatic secretion in piglets after weaning. A total of 16 barrows were weaned at 4 wk of age; 3 d later, they were surgically fitted with a catheter in the pancreatic duct for continuous collection of pancreatic juice. Collections of pancreatic juice were made every other day starting 4 d postsurgically. Piglets fed the fish oil diet secreted a significantly greater volume of pancreatic juice than piglets fed the coconut oil or lard diets. The output [U/(h. kg(0.75))] of lipase was higher in piglets fed fish oil than in piglets fed lard or coconut oil. The output of colipase was greater in piglets fed fish oil and coconut oil than in those fed lard. The dietary treatments did not affect the output of carboxylester hydrolase. The output of trypsin was significantly lower in piglets fed lard than in piglets fed fish oil or coconut oil diets and the output of carboxypeptidase B was greater in those fed the fish oil diet. Protein, chymotrypsin, carboxypeptidase A, elastase and amylase outputs did not differ among the dietary treatment groups. The apparent digestibilities of nutrients and energy were measured in feces and did not differ among groups. Thus, the greater output of lipase in fish oil-fed piglets did not result in a greater digestibility of fat in this diet.

Pancreatic exocrine responses to stimulation of the peripheral ends of the vagus nerves intermittently have been investigated in anaesthetized pigs and compared with the effects of continuous stimulation at corresponding frequencies. At relatively low frequencies < or =20 Hz in bursts or 2 Hz continuously) both the flow of pancreatic juice and the output of protein therein were potentiated by stimulating in bursts. Thus stimulation at 20 Hz in bursts produced a significantly greater flow of pancreatic juice than stimulation at 2 Hz continuously (10.9+/-0.9 compared to 4.8+/-0.7 microl min(-1) (g gland)-1 , respectively; P<0.01). Likewise the output of protein during intermittent stimulation at 20 Hz (144+/-23 microg min(-1) (g gland)-1) far exceeded that produced during continuous stimulation at 2 Hz (49+/-9 microg min(-1) (g gland)-1; P<0.01). Both differences were abolished by atropine (0.5 mg kg(-1) i.v.), which augmented the flow during continuous stimulation (to 8.7 +/- 1.5 microl min(-1) (g gland)-1; P<0.05 at 2 Hz) and substantially reduced the output of protein during intermittent stimulation (to 27+/-7 ng min(-1) (g gland)-1; P<0.01 at 20 Hz in bursts). These results show that a variety of pancreatic exocrine responses can be enhanced by stimulating the parasympathetic innervation in bursts. They are also consistent with the contention that the secretion of protein from the gland, in response to parasympathetic stimulation, is dependent mainly on activation of muscarinic receptors. They confirm that the flow of pancreatic juice is due mainly to the release of VIP and show that, in the absence of atropine, this is restricted by muscarinic inhibition which may be presynaptic as elsewhere.

In pigs, the spontaneous secretion of the exocrine pancreas and the release of cholecystokinin (CCK) and peptide YY (PYY) after intraduodenal infusion of fully saturated synthetic fats differing in chain length was studied. Growing pigs (n = 6) were prepared with pancreatic duct catheters, duodenal T-cannulas and catheters placed in the jugular vein. The pigs were fed 2 g/100 g body twice daily. Beginning with the morning feeding, a medium-chain triglyceride (MCT: glycerol tricaprylate), a long-chain triglyceride (LCT: glycerol tristearate) or saline was infused at a rate of 0.1 g/100 g body. Pancreatic juice was collected, beginning 1 h preprandially until 3 h postprandially. Blood samples were obtained 15 min preprandially and 15, 45, 90 and 150 min postprandially. The infusion of MCT evoked a change in the trend of the curve for the volume of secretion of pancreatic juice, lipase and colipase concentrations and outputs. The trend of the curve did not change over time for CCK and PYY. Differences between the trends of the curves for the saline and MCT treatment were observed for volume of secretion, protein output, lipase content and output, trypsin and colipase output. Differences in the trends of the curves between MCT and LCT were obtained for the outputs of protein, lipase and colipase. Plasma CCK levels were lower as a result of the MCT treatment compared with the saline and LCT treatments. The results suggest an immediate, distinguished response of the porcine exocrine pancreas to fats differing in chain length.

Nonsteroidal antiinflammatory drugs (NSAIDs), including various chemical families of drugs, inhibit prostaglandin synthesis and act on the central nervous system. Prostaglandins are involved in regulation of regional circulations, cell turn-over in the gastrointestinal tract, and in primary haemostasis. The patterns of action of NSAIDs result in analgesic properties, but also in adverse effects. NSAIDs are increasingly used perioperatively, alone or associated with opioids or local anaesthetics, because of their analgesic and opioid sparing properties. Some of their adverse effects, especially ischaemic acute renal failure and gastrointestinal complications, can be life-threatening, and increased haemorrhagic risk is an issue for spinal or epidural anaesthesia in patients taking aspirin. Safe use of NSAIDs is possible in consideration of contraindications (elderly patient, hypovolaemia, cirrhosis, congestive heart failure, renal failure, active gastrointestinal ulcer, bleeding diathesis, pregnancy), and requires close monitoring of renal function if they must be used in patients at risk for renal failure. NSAIDs are not ulcerogenic in the short-term in healthy subjects. They must be used with caution in patients with a preexisting haemostatic defect or undergoing haemorrhagic surgical procedures.

Two experiments were performed to study the effect of feeding diets containing oils with different fatty acid composition on exocrine pancreatic secretions in growing pigs using two different methods to collect pancreatic juice. In the first experiment, three barrows (initial weight 37 kg) were fitted with a pancreatic pouch re-entrant cannula. An isolated pouch was prepared where the pancreatic duct enters the duodenum. In the second experiment, also using three barrows (initial weight 32 kg), a catheter was inserted into the pancreatic duct. Three wheat starch and fish meal-based diets were formulated to contain either 15 g fish oil, rapeseed oil or coconut oil/100 g. In both experiments, the diets were fed according to a 3 times 3 Latin square design. The volume of pancreatic juice secreted, pH and secretion of bicarbonate, protein, amylase, trypsin, lipase and colipase were not significantly affected by the diets in the first experiment. In the second experiment, chymotrypsin secretion was significantly greater in pigs fed the coconut oil diet, and secretion of carboxyl ester hydrolase was significantly higher in pigs fed the fish oil diet. When compared qualitatively, pigs in Experiment 2 secreted more pancreatic juice; the pancreatic juice had a higher pH, and trypsin, carboxyl ester hydrolase and colipase secretions were substantially higher whereas amylase secretion was lower than for pigs in Experiment 1. The fatty acid composition of the different oils had minor effects on exocrine pancreatic secretion in growing pigs. However, there were considerable differences between the two surgical methods used to collect pancreatic juice, and these differences may be explained by physiological changes induced by the two methods.

The effect of dietary pectin on apparent ileal and fecal digestibilities of protein and amino acids and on pancreatic secretions was studied in two experiments with growing pigs (initial weight 70 kg). Four barrows were fitted with simple T-cannulas for collection of ileal digesta; another four barrows were fitted with permanent re-entrant cannulas for collection, sampling and subsequent return of pancreatic juice. Dietary pectin included at a level of 7.5 g/100 g in a cornstarch-based diet significantly depressed apparent ileal and fecal protein and amino acid digestibilities. This depression in the small intestine could be attributed to both an increase in endogenous protein secretions and a decrease in the efficiency of digestion. In the large intestine, pectin was used by intestinal microbes as the principal energy source to catabolize nitrogenous compounds and to stimulate bacterial nitrogen assimilation, thus altering the amino acid profile of protein voided in feces. The inclusion of pectin did not affect the flow of pancreatic juice or the total secretion of protein, lipase, trypsin and chymotrypsin. However, there was a significantly lower secretion of alpha-amylase, which was a direct result of the replacement of starch by pectin. The results demonstrate that pectin may have a detrimental effect on the processes of protein digestion and absorption but does not affect the secretion of pancreatic proteolytic enzymes in pigs.

Mediation of postprandial pancreatic enzyme secretion has been ascribed mainly to cholecystokinin and to vagovagal reflexes. Recent studies suggest that these pathways are subject to feedback regulation. Diversion of pancreatic juice from the duodenum stimulates cholecystokinin release and pancreatic enzyme secretion, and intraduodenal administration of trypsin or chymotrypsin inhibits cholecystokinin release and pancreatic secretion. The increased plasma cholecystokinin levels following diversion of pancreatic juice seems to be mediated by "cholecystokinin-releasing factor", a trypsin-sensitive substance secreted by the proximal small intestine. This factor may mediate pancreatic enzyme secretion in response to protein intake. Dietary protein in the intestine competes for the trypsin that would otherwise inactivate the factor. The resulting increase of this factor in the intestinal lumen releases cholecystokinin and stimulates pancreatic enzyme secretion. Enteropancreatic reflex can also be activated by distension or administration of hyperosmolar solutions in the duodenum eliciting pancreatic enzyme secretion without raising plasma cholecystokinin levels. This effect is inhibited by atropine, suggesting that it is cholinergically mediated. Pancreatic response to duodenal volume or osmolality is not suppressed by trypsin, indicating that the reflex is not affected by intraluminal proteases. Our studies also show that secretion of pancreatic polypeptide is under cholinergic control, and this peptide acts by interfering with cholinergic transmission, making it an ideal candidate to modulate pancreatic secretion stimulated by the vagal cholinergic pathway. Similar observations are made with somatostatin and calcitonin-gene related peptide which also acts preferentially to inhibit pancreatic secretion by the vagal cholinergic pathway.

Calcium concentration of pancreatic juice depends on secretion of calcium bound to enzymatic proteins or calcium diffusion from interstitial fluids. To evaluate the relative magnitude of these pathways, we studied the influence of hypercalcemia on ionized calcium (Ca++) in dog pancreatic juice. Pancreatic juice was collected during basal secretion and during stimulation by secretin or secretin plus caerulein in control conditions and under CaCl2 infusion. [Ca++] was measured by selective electrodes. Saturation of juice in CaCO3 was calculated. In stimulated juice, total calcium concentration ([CaT]) and [Ca++] were unchanged by hypercalcemia. In basal juice, composition was profoundly modified by hypercalcemia because [CaT] (3.31 +/- 0.89 mmol/L vs 1.80 +/- 0.44 for controls), [Ca++] (1.44 +/- 0.37 mmol/L vs 0.84 +/- 0.24 mmol/L for controls), and the index of saturation in CaCO3 (5.2 +/- 2.4 vs 2.9 +/- 1.8 for controls) increased significantly. Protein concentration was unchanged. This suggests that in basal conditions, the relationship between plasma and juice calcium levels is due to passive interstitial Ca++ diffusion through the pancreatic ducts. In accordance with the hypothesis of a restricted calcium diffusion, the effects of hypercalcemia were flow rate dependent, being less pronounced when basal flow rate increased. It is concluded that, in the dog, the calcium species found in stimulated juice result from a redistribution of calcium secreted along with proteins, whereas at low secretion rate, juice calcium level depends mainly on interstitial Ca++ diffusion into the main pancreatic ducts.

We have studied the effect of increasing concentrations of Brefeldin A (BfA) on the rate of secretion in vitro of pulse-labeled proteins and individual enzymes and on the fine structure of the Golgi apparatus in pancreatic acinar cells derived from control rats and from animals stimulated in vivo by feeding a synthetic proteinase inhibitor (FOY 305). A half-maximal inhibition of intracellular transport of newly synthesized proteins was observed at 0.125 microgram/ml BfA which in FOY-stimulated pancreatic lobules was more pronounced. The Golgi apparatus at this low dose of BfA was still preserved and consisted of stacks of narrow cisternae devoid of secretory material. Granule formation from the trans-Golgi network (TGN) was greatly reduced. A nearly complete inhibition of both total protein and individual enzyme transport was observed at 0.5 microgram/ml BfA. This inhibitory effect was more pronounced with enzyme proteins which are transported slowly through the cellular compartments (e.g. lipase) as compared to faster moving proteins (e.g. chymotrypsinogen). The Golgi apparatus at 0.5 microgram/ml BfA was fragmented into clouds of small uniform vesicles which were stained with an antibody directed against TGN 38 and which were surrounded by a network of tubular membranes reacting with an antibody against p58, a marker protein of the intermediate compartment between rough endoplasmic reticulum (RER) and Golgi. Incubation of pancreatic lobules in 10 micrograms/ml BfA led to a disappearance of the small vesicles and a relocation of TGN 38 into the RER, while the tubuloreticular membranes of the intermediate compartment remained unaffected. Aggregates of clathrin cages devoid of membranes accumulated in the area of the previous Golgi vesicles. The inhibitory effect of 0.5 microgram/ml BfA on both intracellular transport and Golgi fine structure was readily reversible within 15 to 30 min upon removal of the drug, but took 1 h or longer after incubation in 5 or 10 micrograms/ml BfA.

Expression of the CCK-A receptor gene in the pancreas and pancreatic exocrine function was examined in diabetic model rats (OLETF) at 5 wks of age. Little or no CCK-A receptor was detected in the pancreas of OLETF rats. Pancreatic exocrine function in response to exogenous CCK and to bile-pancreatic juice diversion (endogenous CCK) was impaired in conscious OLETF rats. The pancreatic insulin and protein contents of OLETF (Otsuka Long-Evans Tokushima Fatty) and control LETO (Long-Evans Tokushima Otsuka) rats were not significantly different. No histological abnormalities or expression of pancreatitis associated protein (PAP) mRNA was detected in the pancreas in either group. These results suggest that OLETF rats are a new experimental model for congenital deficiency of CCK-A receptor in the pancreas.

Circulating molecular forms with pancreastatin (PST)-like immunoreactivity in plasma from normal subjects were examined. An immunoreactive form corresponding to a human PST-like sequence [human chromogranin-A-(250-301)] (hPST-52) and a larger form (mol wt 15-21 kDa) were detected by gel filtration of plasma from normal subjects. On high performance liquid chromatography, predominant immunoreactive forms coeluted with the three larger forms which were purified from the xenograft of human pancreatic islet cell carcinoma cell line QGP-1N cells and with synthetic hPST-52. The fraction containing larger forms purified from xenograft of QGP-1N cells had biological activity equivalent to that of hPST-52 on the inhibition of pancreatic exocrine secretion. These results suggest that the larger molecular forms as well as hPST-52 may be physiologically important circulating forms of PST in human.

Intestinal atrophy contributes to the clinical difficulties of patients who cannot eat normally. Atrophy is prevented by luminal food proteins but not by the equivalent aminoacids. This observation is not explained by current theories of intestinal physiology. Epidermal growth factor (EGF) and transforming growth factor alpha (TGF alpha) are secreted into the gut lumen. We speculated that these are digested by pancreatic enzymes in fasting juice, but preserved when food proteins block the active sites of these enzymes. Studies based on molecular size and bioactivity confirmed that fasting human jejunal juice destroys EGF and TGF alpha. EGF, but not TGF alpha, was preserved when the milk protein casein or an enzyme inhibitor were present; elemental diets were ineffective. Diversion of pancreatic juice to the mid point of the small intestine in rats significantly increased luminal EGF-like bioactivity and all variables of growth in the proximal enzyme-free segment. Our findings support a novel mechanism of control of intestinal growth, which has important clinical implications. The addition of enzyme-inhibiting proteins such as casein to elemental diets may preserve intestinal integrity and function.

GP2 is the major glycoprotein component of the zymogen granule membrane of pancreas acinar cell. It was recently found that this protein is secreted and forms a network of fibrils in pancreatic juice. In the present work, with an ELISA, we have examined the fluctuations of GP2 levels in the juice collected in resting and stimulated conditions. In anaesthetized fasting rats, GP2 represented about 6-8% of total protein output. Stimulation by caerulein, carbachol, or their combination caused an immediate and significant burst in both protein and GP2 outputs. However, the GP2 increase did not parallel protein release. Its relative proportions decreased with the intensity of the stimulus. The secretory behavior of GP2 cannot be explained with the current concepts of constitutive and regulated pathways of secretion and suggests the existence of a yet undefined mode of secretion for this protein.

It has been proposed that modulation of cholecystokinin (CCK) release by proteinases, proteinase inhibitors and protein is mediated by a pancreatic secretory trypsin inhibitor (PSTI), also called monitor peptide, in the rat. When human [125I]-PSTI was incubated with fasting small bowel juice or activated pancreatic juice greater than 88% of tracer eluted from gel chromatography in the characteristic position of hydrolysed PSTI. However, when the small bowel juice had been pre-incubated with soybean trypsin inhibitor 3 g/l, casein 5 g/l or lactalbumin 30 g/l, the hydrolysis of PSTI diminished so that 95%, 32%, and 33% respectively, now eluted in the characteristic position of free (i.e. intact and not bound to an enzyme) PSTI. When [125I]-PSTI was incubated with pure trypsin, chymotrypsin, elastase or enterokinase greater than 95% of tracer eluted in the position of PSTI-enzyme complex. Incubation of PSTI with trypsin plus one other enzyme was required to produce hydrolysis. The degree of protection of PSTI from hydrolysis in duodenal juice produced by these substances correlates with their affects on CCK release. Our findings support the hypothesis that PSTIs mediate the modulation of CCK release by intraluminal proteinases, proteinase inhibitors and proteins.

GP-2 is the major secretory granule membrane glycoprotein of the exocrine pancreas and appears in the pancreatic juice in a modified sedimentable form. We have localized GP-2 in the rat pancreas at the electron microscopic level using affinity-purified antibodies and found it to be concentrated in the zymogen granules and in the acinar lumen. Label was also present on the apical and basolateral plasma membranes but prior treatment of the sections with periodate to eliminate the contribution of highly antigenic oligosaccharide moieties reduced substantially the staining of the basolateral surface. Approximately 45% of the GP-2 in the granules was not membrane-associated but appeared instead in the granule lumen. Parallel biochemical characterization of GP-2 in isolated secretory granules demonstrated that 60% fractionated with the membranes after granule lysis while 40% remained in the content fraction. Unlike the membrane-associated form of the protein, which is linked to the membrane via glycosyl-phosphatidylinositol (GPI), GP-2 in the content did not enter the detergent phase upon Triton X-114 extraction; nor was it sedimentable at 200,000g, as is characteristic of the form collected in the pancreatic juice. In addition, GP-2 in the pancreatic juice was recovered in the aqueous phase during Triton X-114 extraction and yet remained sedimentable after detergent extraction, demonstrating that its ability to remain in large aggregates was independent of lipid. These results are consistent with a life cycle for the protein that begins with synthesis of a membrane-associated precursor that can be converted by lipolytic or proteolytic cleavage to a soluble form within the zymogen granule. Further modification to a sedimentable form may then occur in the pancreatic juice.

The function of pteroylpolyglutamate hydrolase (PPH) of pancreatic secretion in the hydrolysis of dietary polyglutamyl folates (PteGlun) in humans is unclear. In this study, PPH was detected in pancreatic juice collected from pigs during both fasting and postprandial conditions. The secretion of PPH was markedly increased following feeding. Pancreatic PPH showed the following characteristics: 1) endo/random hydrolysis of gamma-glutamyl peptide bonds of Pte-Glun substrates, yielding folic acid as the terminal product; 2) maximum activity at pH 4.0-4.5 and maximum stability at pH 7.0; 3) stimulation of activity by Zn2+ and 2-mercaptoethanol; 4) Km values for pteroyltriglutamate (PteGlu3) of 28.7 microM at pH 4.0 and 9.1 microM at pH 5.0; 5) apparent molecular weight of 29,000; and 6) isoelectric point within the range of 8.5-9.0. On the basis of PPH activity, volume of the postprandial secretion and pH profile of enzyme activity, it is suggested that pancreatic PPH may act in vivo in folate digestion and absorption to initiate the deconjugation of dietary PteGlun prior to the action of jejunal brush border PPH.

There is no etiologic treatment for acute necrotizing pancreatitis. Advances in intensive care resulted in a reduction in early death rate by a better control of systemic complications. Delayed death rate from infection is high (20-60%). Diagnostic problems are an important cause, in spite of the aid of computed tomography and echography. The prognosis will further be improved by earlier diagnosis, a better definition of surgical treatment when complications arise, and constant medicosurgical collaboration.

A method is described to measure in vitro the extent of isotopic exchange between the native nonheme food iron and added inorganic reduction to radioiron tracer. The food is digested with pepsin and trypsin in the presence of radioiron. The exchangeability of food iron is calculated from the specific activity in the food and in an extract of bathophenantroline in isoamyl alcohol obtained after digesting this food. The precision and accuracy of the method is illustrated by two kinds of studies, those in which different amounts of contamination iron are added to a meal and those evaluating contamination iron in natural meals. The present method will make it possible to measure validly iron absorption from meals contaminated with unknown amounts of iron of unknown exchangeability with the extrinsic radioiron tracer.

Five Beagle dogs, equipped with duodenal and gastric fistulae, were fed a standard diet before receiving the same diet supplemented with wheat bran for 1 month. Pancreatic secretory investigations performed in conscious animals before and 1 month after bran administration showed a significant parallel increase in the flow rate of pancreatic secretion and the outputs of bicarbonate and amylase both in basal and secretin-stimulated conditions. The outputs of protein and chymotrypsin increased only in unstimulated secretions, while the output of lipase was strongly reduced in response to secretin. However, the small intestinal mucosa was not affected by bran administration. Dietary fiber did not alter the height of the villi or the activity of sucrase, maltase and aminopeptidase in mucosal homogenates or isolated brush border membranes from intestinal biopsies. These data suggest that wheat bran supplemented to the standard diet affects the exocrine pancreatic secretion but not intestinal enzyme activities involved in the absorption of carbohydrates and proteins in the dog.

The effects on pancreatic secretion of a diet supplemented with wheat bran for one month were studied in five dogs provided with chronic pancreatic and gastric fistulae. Dogs were subjected before and after bran administration to a continuous intravenous infusion of secretin (GIH, 0.5 U/kg/h) alone and a combination of secretin with cerulein (25 or 100 ng/kg/h). Exocrine pancreatic secretions under basal conditions were collected during the intravenous infusions of normal saline. Wheat bran supplementation for 4 wk to the standard diet in dogs increased pancreatic juice flow rate along with bicarbonate and amylase output whether the secretion was unstimulated or stimulated with caerulein alone or combined with secretin. No significant changes in the concentration of pancreatic bicarbonate, amylase, chymotrypsin, and proteins were noted under stimulated conditions. Furthermore, lipase concentration and output were dramatically reduced. These data indicated that wheat bran supplemented to the standard diet in dogs affects the exocrine pancreatic secretion whether it was unstimulated or stimulated by secretin alone or combined with cerulein.

The effects of glucagon-(1-21)-peptide on pancreatic exocrine secretion and plasma glucose levels were studied and compared with those of native glucagon in anesthetized dogs. Intravenous bolus administration of 1 nmol or 10 nmol/kg of glucagon-(1-21)-peptide evoked a significant inhibition of secretin-stimulated pancreatic juice secretion and protein output in a dose-dependent manner, as equimolar doses of glucagon did. Native glucagon induced an immediate and transient increase in pancreatic juice volume, which was followed by a significant inhibition. However, glucagon-(1-21)-peptide showed only the inhibitory action. Glucagon-(1-21)-peptide had no effect on plasma glucose levels even when a dose of 10 nmol/kg was given. The results suggest that the N-terminal amino-acid residues of glucagon play an important role in the inhibition of pancreatic exocrine secretion.

Neuromedin-N, a novel neurotensin-like peptide, has recently been identified from porcine spinal cord by using a bioassay for a stimulatory effect on guinea pig ileum. The amino acid sequence of the peptide has been determined to be Lys-Ile-Pro-Tyr-Ile-Leu, which is quite homologous to the COOH-terminal sequence of neurotensin. In this study, the effect of neuromedin-N on pancreas and splanchnic blood flow was investigated in eight dogs. Intravenous injections of graded doses of synthetic neuromedin-N caused a dose-dependent decrease of systemic arterial pressure and a dose-dependent increase in both portal and superior mesenteric arterial blood flow, which were measured with transit time ultrasonic flow meter. Volume and protein output of the pancreatic juice were also increased significantly by Neuromedin-N. Pancreatic capillary blood flow measured with laser Doppler flowmetry was increased in a dose-related manner. The present study first demonstrated that neuromedin-N retains a potent stimulatory effect on the pancreas and splanchnic circulation, indicating that this peptide is one of the biological active forms of neurotensin-like peptide in mammals. This study also leads to the suggestion that this peptide possesses physiological significance as a novel neuropeptide.

We examined the effects of atrial natriuretic polypeptide (hANP) on exocrine function in the isolated and blood-perfused dog pancreas in situ. Intra-arterial injection of hANP (1-10 micrograms) resulted in the dose-dependent increases of the pancreatic juice secretion. The secretory activity of 3 micrograms of hANP was approximately equal to one third of the secretory activity of 0.1 units of secretin. The use of hANP increased the concentration of bicarbonate but not that of sodium and protein in the pancreatic juice as compared with the basal values. These secretory responses to hANP were not inhibited by treatment with haloperidol, sulpiride, phentolamine, propranolol, atropine, cimetidine or ethacrynic acid. These results suggest that hANP acts directly on the pancreatic exocrine gland to stimulate pancreatic secretion; without, however, increasing sodium excretion. The mechanism of this effect remains to be elucidated.

The effects of dose, pH, and osmolarity on the nasal absorption of a secretin solution were studied in rats. The nasal absorption of secretin was determined by measuring the increased secretion of pancreatic juice, and this was compared with the same response on intravenous administration. The relative bioavailability of secretin on intranasal administration compared with intravenous administration, as estimated from the pharmacological response, was approximately one-tenth. It was enhanced in acid solution and reached a maximum in a 0.462 M sodium chloride solution.

Secretin was purified from the first 50 cm of proximal intestine of a single dog. The purification sequence included extraction in acid-ethanol, differential precipitation with acetone, Sephadex gel filtration and three successive HPLC steps. Dog secretin has the following sequence: HSDGTFTSELSRLRESARLQRLLQGLV. The underlined amino acid represents a substitution of Glu for Asp at position 15 from the NH2-terminus of pig secretin. Dog secretin is equal in potency to pig secretin in stimulating pancreatic ductal flow in a rat bioassay system.

To determine if zinc homeostasis occurs by zinc output from bile-pancreatic secretions, the bile-pancreatic duct and intestine of rats were surgically cannulated, and bile-pancreatic fluid was collected 2 h/d from the day of surgery to 8 d after surgery. The rats were fed diets containing 10, 100 or 1000 micrograms Zn/g diet before and after surgery. The effect of surgery itself was significant; food intake was initially lower than presurgery levels, but returned to presurgery levels by d 5. Protein and zinc concentrations, and carboxypeptidase A (CpA) and carboxypeptidase B (CpB) activities in bile-pancreatic fluid increased after surgery and leveled off at approximately d 6. Among the dietary zinc groups, the concentration of zinc in bile-pancreatic fluid varied significantly, whereas concentrations of calcium and copper did not. Zinc concentration in bile-pancreatic fluid for d 1-8 postsurgery averaged 1.8, 3.2 and 4.4 micrograms Zn/g, in the groups fed 10, 100 and 1000 micrograms Zn/g diet, respectively. Because the percent of zinc ingested that was secreted in bile-pancreatic fluid, estimated to be 57, 9.5 and 1.2% for the groups consuming the diets containing 10, 100 and 1000 micrograms Zn/g diet respectively, was not similar in the three groups, the quantity of zinc in bile-pancreatic fluid is not proportionally related to the amount of zinc ingested. Our results therefore suggest that zinc secretion in bile-pancreatic fluid does not play a major role in zinc homeostasis. Molecular localization of zinc in bile-pancreatic fluid and measurement of activity of CpA and CpB indicated that zinc in bile-pancreatic fluid is associated primarily with these digestive enzymes.

A new factor which activated the secretion of pancreatic enzymes was discovered and purified from rat bile-pancreatic juice. A fraction below M.W.10,000 of rat bile-pancreatic juice enhanced trypsinogen secretion by injection into anesthetized rat duodenum. The factor was purified from this fraction using its biological activity as an index by Sephadex G-50, SP Sephadex C-50 and HPLC. This factor was a peptide of which molecular weight was about 6,000 and had trypsin inhibitory activity. From these and some other findings, it was suggested that the peptide was identical with the "Kazal type" inhibitor. In the anesthetized and atropine-treated rat, of which intestinal trypsin was removed by thoroughly washing with saline containing 5 microM soybean trypsin inhibitor (SBTI), pancreatic secretion became basal state, and was not stimulated by injection of SBTI into its duodenum any longer. Under this condition, however, injection of this purified peptide brought about markedly stimulation of pancreatic enzyme secretion. These results suggest that this peptide has a certain function which enhances pancreatic enzyme secretion by the different manner from exogenous trypsin inhibitors such as SBTI.

The technique of freeze fracture was used to visualize triglyceride (TG) hydrolysis and the production of lipolytic products (LPs) in vitro and in vivo in the presence of bile salts (BS). Three systems were investigated: pure lipolytic products (oleic acid and monoolein) in the presence of a pure bile salt (taurodeoxycholate (TDC)), lipolytic products produced from TG by pancreatic lipase in the presence of a variety of bile salts, and lipolytic products produced in the intestine of the killifish, Fundulus heteroclitus, after fat feeding. In vitro, lamellae (4-5 nm thick with 0-8-nm water spacings) appeared on the surface of TG droplets in all preparations with LP/BS molar ratios of 1.5 or greater and spherical vesicles (diameter range, 20-130 nm) were produced from these lamellae. With model killifish bile (taurocholate-cholate 1:1) at LP/BS ratios between 1.5 and 4, homogeneous vesicles or particles (mean diameter, 23.8 nm) were produced by lipase at pH 6.9. In vivo, lamellar product phases also occurred after fat feeding. The smallest visible LP/BS structures by freeze fracture electron microscopy were approximately 20 nm globular particles. Large disc-shaped micelles either were not present or were below the resolution limit of the replica (approximately 10 nm). The dominant aggregated lipolytic product phase was composed of multiple layers of rough-textured lamellae. No evidence of cubic structure was seen. These results show that lamellar and vesicular lipolytic product phases can be intermediates in intestinal fat digestion. However, no evidence for the direct endocytotic absorption of these product phases by the intestinal microvillus membrane was found.

Segmental pancreatic transplantation is now the most widely favoured form of pancreatic transplantation, but the major difficulty with this procedure is the handling of the exocrine secretion. The use of a pancreaticoenteric anastomosis for exocrine diversion has been re-evaluated and several ancillary measures to reduce the risk of fistula and bacterial contamination have been applied. In three consecutive patients there have been no complications related to the exocrine pancreas. The pancreatic and renal grafts of these patients are functioning well 7, 3, and 2 months, respectively, after transplantation.

White Leghorn hens, 14 to 29 wk of age, were surgically prepared with cannulae for collecting secretions from the cystic duct and the duct draining the ventral pancreatic lobe and for infusing the jugular vein with avian pancreatic polypeptide (aPP) or saline. A plasma infusion rate that produced a plasma level of 15 ng of aPP/mL was used. A comparison of values obtained during saline infusion with those obtained during aPP infusion indicated that pancreatic and biliary secretory volumes and pancreatic total protein concentration were significantly depressed by aPP. The pH of pancreatic and biliary secretions were not significantly affected by aPP. Because aPP also depresses gastric secretion and motility in hens, it is proposed that its physiological role may be to oppose or modulate the actions of other, stimulatory gastrointestinal hormones.

Pancreatic enzyme output in response to various purified diets was studied in rats surgically prepared so that pancreatic secretion could be continuously collected, assayed and returned to the intestine. Intraduodenal infusion of phenylalanine and tryptophan alone did not stimulate secretion. Diets containing phenylalanine, tryptophan, a mixture of amino acids, or hydroxyzed casein, fed intragastrically, evoked a small pancreatic response that was similar to the response to a protein-free diet. intragastric infusion of a diet containing 18% casein stimulated a large initial secretion of enzyme that remained elevated throughout the 5.5 hour experiment. Addition of soybean trypsin inhibitor (SBTI) to the diet increased the pancreatic response over that due to dietary casein alone. When pancreatic juice was diverted from the intestine, the large pancreatic responses to casein or to casein + SBTI were greatly reduced and the response was similar to that of the protein-free diet.

Transmucosal transport rates for triolein in proximal and distal intestine were compared in unanesthetized rats. Emulsified [1-14-C] triolein together with bile and pancreatic juice from donor rats was infused for 6 hr into either the duodenum or the midpoint of the small intestine at such a rate that absorption was essentially complete in both regions of the intestine. Lymph was collected from the thoracic duct during triolein infusion and for an additional 6-hr period. The decrease in the rate of lymphatic output of labeled fat was found to follow a simple exponential function in all animals. This rate of decrease (decay rate) was used to calculate the half-times of lipid turnover through the intestinal wall and the fractional output rates. Distal intestine transported lipid 40% more slowly than proximal intestine, and the difference was associated with a greater accumulation of triglyceride in the distal intestinal wall. Chylomicron synthesis and/or release is the rate-limiting step for distal lymphatic fat transport in vivo, whereas fat uptake from the lumen is rate limiting for proximal intestine.