Pancreatic Enzyme Content Research Articles

Effects of Manganese Deficiency and Dietary Composition on Rat Pancreatic Enzyme Content

Recent studies show that manganese (Mn) deficiency increases pancreatic amylase content. Pancreatic adaptation to dietary composition also alters enzyme content. The present study investigated whether Mn deficiency alters pancreatic adaptation to diet. Weanling rats that were fed for 6 wk a high carbohydrate (HC) diet with <1 mg Mn/kg diet (Mn deficient) or 40 mg Mn/kg diet (control) were divided into three control and deficient dietary subgroups: 1) HC, 2) high protein (HP) or 3) high fat (HF). Rats were then fed these diets for 10 d. Body weights and food consumption were comparable among the groups. Pancreatic and hepatic Mn contents were significantly lower in Mn-deficient rats than in respective controls. Digestive enzymes adapted to diet in both control and Mn-deficient rats with the greatest amylase, lipase and trypsin activities in HC, HF and HP rats, respectively. Mn deficiency resulted in significantly greater amylase activity in HC and HP groups and lipase activity in only the HF group than in respective controls. These data suggest that Mn participates in the regulation of pancreatic amylase content and in the adaptive response of pancreatic lipase to dietary fat.

Small bowel bypass prevents the trophic action of cholecystokinin on the rat pancreas

The effect of a chronic administration of cholecystokinin (CCK) on the rat pancreas has been studied in rats subjected to a 90% jejunoileal bypass or an intestinal transection (controls). Jejunoileal bypass, when compared to transection, did not modify the size of the pancreas but decreased its enzyme content, especially for amylase, and reduced the number of zymogen granules. These structural and biochemical changes were maintained when bypassed animals were treated three times daily and for six days with cholecystokinin (20 Ivy Dog Units (IDU)/kg). In contrast, CCK treatment in transected animals induced growth of the pancreas due to cellular hypertrophy and hyperplasia; pancreatic enzyme content, especially for chymotrypsin, and the population of zymogen granules in acinar cells were also enhanced. It is concluded that jejunoileal bypass prevents the trophic action of chronic CCK on the pancreas.

Effect of parental malnutrition on enzyme content of rat pancreas

The aim of this study was to assess in rat pups the influence of protein diets ingested by their mothers during gestation and lactation on the enzyme content of the pancreas of the offspring. Rat pups born of either well-nourished mothers or of mothers fed a diet moderately restricted in protein (9% casein w/w) were studied. After weaning, the pups were fed on one of three diets: a well-balanced diet, a 5% casein diet (protein restricted), or a well-balanced diet of a similar caloric value as the protein-restricted diet (pair-fed rat pups). The pups were sacrificed after intervals of one to 25 weeks after weaning. The results showed that the enzyme content of the pancreas increased progressively with time in pups born of malnourished mothers, particularly in pups fed the protein-restricted diet. This suggests prolonged maturation of the pancreas. Pups fed the 5% casein diet had a decreased amylase content per milligram of DNA but not of other enzymes. Malnutrition in the mother increased the ratio of enzymes to DNA and the total pancreatic enzyme content at different times after weaning, indicating that maternal malnutrition had a prolonged effect on the pancreatic enzyme content of the pups' pancreas. This mechanism could play a role in the pathogenesis of tropical chronic calcific pancreatitis in man and explain some of the geographic differences in the incidence of the disease.

Raised serum concentrations of pancreatic enzymes in cigarette smokers.

Circulating concentrations of digestive enzymes, certain lysosomal hydrolases and protease inhibitors were measured in 19 heavy smokers and 13 non-smokers before (basal) and at 15, 30, and 60 minutes after a single intravenous injection of secretin (75 CU). In smokers, basal serum amylase and immunoreactive pancreatic elastase 2 (IRE2) concentrations were about 100% and 25% higher respectively, than in the non-smokers, whereas, no differences were observed in basal immunoreactive cationic trypsinogen (IRCT) concentrations and in acid phosphatase and beta-glucuronidase activities between the two groups. Furthermore, a single injection of secretin to cigarette smokers significantly increased serum amylase, IRCT and IRE2 by 155%, 200%, and 100%, respectively when compared with their corresponding basal levels. No such increment was observed in the non-smokers. In addition, there were no significant differences in serum trypsin or elastase inhibitory capacity or immunoreactive alpha 1-protease inhibitor and alpha 2-macroglobulin levels between smokers and non-smokers. The levels and inhibitory capacity of these protease inhibitors was also not affected by secretin injection. These data suggest that cigarette smoking enhances the responsiveness of the exocrine pancreas to a physiological stimulus such as secretin, with resultant substantial increase in the concentrations of pancreatic hydrolases in blood.

Cerulein induces hyperplasia of the pancreas in a rat model of chronic pancreatic insufficiency.

Chronic pancreatic insufficiency (CPI) was induced in male Wistar rats by the injection of a zein-oleic acid-linoleic acid solution into their pancreaticobiliary ducts. Animals injected developed severe pancreatic atrophy with fibrosis and greater than 90% loss of pancreatic enzyme content. The animals also developed malabsorption of fat and bentiromide. Three weeks after the CPI lesion was induced, animals were randomized to receive cerulein 2 micrograms/kg twice daily subcutaneously or saline twice daily subcutaneously for 2 weeks. Cerulein significantly increased pancreatic trypsinogen (p less than 0.03), amylase (p less than 0.01), lipase (p less than 0.02), DNA (p less than 0.02), and RNA (p less than 0.01) content and improved fat and bentiromide malabsorption as compared to saline (p less than 0.05). We conclude that cerulein therapy can cause significant hyperplasia of pancreatic acinar parenchyma in an animal model of CPI and that this therapy can partially reverse malabsorption.

Salivary amylase and pancreatic enzymes in Sjögren's syndrome.

Concentrations of immunoreactive trypsin (IRT) and pancreatic and salivary amylase activities were measured in 22 patients with primary Sjögren's syndrome (SS) and in 13 patients with secondary SS. Nineteen of the 22 patients with primary SS had above-normal IRT, and six had above-normal pancreatic isoamylase activity. Six of the 13 patients with secondary SS had above-normal IRT; none had above-normal isoamylase activities. Serum IRT and pancreatic isoamylase were correlated significantly (r = 0.7; p less than 0.0001). Above-normal values for IRT and pancreatic isoamylase were more frequent in patients who had SS for longer than 10 years, but were not related to the presence of salivary gland autoantibodies or to salivary isoamylase activity. We conclude that the concentration and activity of pancreatic enzymes are frequently abnormal in SS; that the abnormality is greater and more frequent in patients with primary SS; and that it increases with the duration of the disease.

Alterations of Pancreatic Digestive Enzyme Content in the Manganese-Deficient Rat

Previous studies suggest that manganese (Mn) may regulate pancreatic exocrine function. In this study, the effects of Mn deficiency on the pancreatic exocrine enzyme content and postweaning development were examined in male weanling Sprague-Dawley rats fed a high carbohydrate diet with 40 ppm Mn (control) or 0.5 ppm Mn (Mn deficient) for 1–10 wk. Pancreatic and hepatic Mn content were 50 and 39% of respective controls in Mn-deficient rats at wk 4. Pancreatic amylase activity was significantly (P < 0.05) higher at wk 8 and 10 in Mn-deficient rats than in controls. Mn deficiency did not alter pancreatic lipase, chymotrypsin or trypsin activities. Dietary Mn repletion restored pancreatic Mn content but did not reverse the elevated pancreatic amylase. These results suggest that Mn may play a complex role in the postweaning development of the exocrine pancreas and the regulation of pancreatic amylase.

Adaptive Changes in Rat Exocrine Pancreas following Subtotal Colectomy

Subtotal colectomy was performed in 17 rats. After 2 or 4 weeks the entire pancreas was excised and isolated pancreatic lobules were incubated for 60 min in Krebs-Ringer-Hepes solution either with or without addition of ceruletide (5 X 10(-10) g/ml). Amylase was determined every 15 min in the supernatant medium. Amylase, trypsin, DNA and total protein were measured in homogenized pancreatic tissue. Morphology was performed via light-microscopy analysis. Two weeks after subtotal colectomy we found an increase in pancreatic wet weight, enzyme and protein content, cellular size and secretion capacity in vitro, whereas DNA concentration in relation to pancreatic tissue weight in grams decreased. These changes pointed to pancreatic hypertrophy. Four weeks after surgery, pancreatic wet weight, enzyme content and DNA content as well as in vitro amylase discharge increased, whereas cellular size remained unchanged compared to controls and sham-operated rats. These changes were indicative of pancreatic hyperplasia.

Pancreatic size and enzyme contents after vagal deafferentation in jejunectomised pigs under free or restricted feeding.

A factorial experiment was designed to test under different feeding levels the effects of the surgical deprivation of sensory afferences (deafferentation) arising from the gastrointestinal tract, including the intestinal chemosensitivity, on the jejunectomised pig used as a model. Within 28 days, the limited jejunectomy failed to affect the pancreas and the enzyme activities were not affected by the feeding level (within the limit of 70% of ad libitum). It was shown that the deafferentation induced significant reductions in the pancreatic tissue mass and in the various enzyme activities, thus suggesting the possible importance of intestinal sensibility for the pancreas.

Pancreatic secretion in the rat influenced by the low molecular weight serine proteinase inhibitor Gabexate mesilate.

The effect of intravenous or intragastric administration of the synthetic proteinase inhibitor Gabexate mesilate (GM) on the pancreas of rats was investigated. Infused intravenously at 4 mg kg-1 h-1, GM inhibited both basal or cerulein (0.2 microgram kg-1 h-1)-stimulated pancreatic protein secretion. Intracellular transport and secretion of newly synthesized pancreatic enzymes was not influenced by intravenous infusion of GM. Intragastric administration of GM (400 mg kg-1) on four consecutive days increased pancreatic wet weight, protein and enzyme content of the gland. A preferential increase of proteinases above glucosidases was observed. Pancreatic lobules from inhibitor-treated rats released 30% less amylase in response to cerulein or carbachol when the rate of discharge was expressed in percent of initial content. Expressed in ku amylase/microgram DNA secretion rate was two-fold higher than in controls. In pancreatic duct cannulated rats GM (400 mg kg-1 h-1), introduced intragastrically on five consecutive days, stimulated volume-bicarbonate and protein secretion rate, the secretory response on the fifth day being significantly higher than on the first day. Enzyme pattern in pancreatic juice changed characteristically: mainly the amount of acidic proteinases increased, whereas the amount of the basic isoforms was altered only slightly.

Rat exocrine pancreas following total gastrectomy

Sixteen rats underwent a total gastrectomy with an end-to-end anastomosis between the esophagus and duodenum. After either two or four weeks, the entire pancreas was excised and isolated lobules were incubated for 60 min in Krebs-Ringer-Hepes solution either with or without addition of ceruletide (5 X 10(-10) g/ml). Amylase was determined every 15 min in the supernatant medium. Measurements of amylase, lipase, trypsin, DNA and total protein were carried out in the homogenized pancreatic tissue. Morphometry was performed via light microscopic analysis. Two weeks following gastrectomy there was an increase in pancreatic wet weight, DNA, total protein and enzyme content (except lipase). Four weeks after surgery, pancreatic weight, amylase and trypsin increased further, whereas DNA content and lipase content remained stable. The DNA concentration decreased, and the size of exocrine pancreatic cells increased. In vitro, amylase discharge increased only after four weeks. The experiments demonstrate a short-term adaptation of the rat exocrine pancreas following total gastrectomy in the form of cellular hyperplasia (after 2 weeks), and hypertrophy (after 4 weeks), and enzyme dissociation.

Effect of short- and long-term alcohol feeding in rats on pancreatic enzyme content and enzyme secretion in isolated pancreatic lobules in vitro

The effect of short- and long-term ethanol intake on digestive enzyme secretion was determined in isolated pancreatic lobules of rats. Groups of male Wistar rats were fed a modified Lieber-DeCarli diet containing either 5% (w/v) of ethanol, isocaloric amounts of a liquid diet in which ethanol was substituted by starch, or solid rat chow; for 3 days, 1, 2, 4, 8 and 12 weeks. Basal and caerulein-stimulated secretion of lipase, amylase, chymotrypsin and trypsin and the enzyme content in the tissue were studied. Feeding the liquid control diet decreased the tissue content of the four enzymes as compared with the values obtained in the group receiving solid rat chow. While basal and stimulated amylase secretion was markedly reduced in the former group, the secretion pattern of the other enzymes exhibited only transient changes. Caerulein-stimulated secretion of lipase and the proteases was increased by ethanol, the effect being more pronounced during the initial phase of the experiment. Alcohol feeding stimulated the basal secretion of these enzymes only in weeks 1-4. In contrast to the other enzymes, basal and stimulated amylase secretion was not enhanced by ethanol feeding. The results suggest that the enzyme secretion of the rat pancreas is distinctly altered by chronic ethanol feeding. However, the response of the pancreatic enzymes is non-parallel, and changes with the duration of alcohol intake.

絶食に伴うラットすいアミラーゼ活性の低下

The present study was undertaken to determine whether starvation could affect the exocrine pancreatic function in the rats. Male Wistar-Imamichi rats of 9 weeks of age were starved and changes in concentration of pancreatic enzymes during starvation period were examined. Amylase concentration started to drop from day 3 of starvation and decreased progressively to a level of 20% of that in the control rats on day 12. The concentrations of protease and trypsin, however, remained relatively unchanged by day 3 or 6, from that time, started te increase. Protease concentration reached a value, three and half times higher than that of the control rats on day 12. Plasma glucose concentration showed a slight decrease in the starved rats as compared to the control rats during starvation period. Plasma insulin level, in contrast, in the rats starved for 3 days was about one-tenth of that in the control rats. A treatment of insulin prevented a decrease in amylase concentration in the starved rats. Similar changes in pan reatic enzyme concentrations, decrease in amylase and increase in protease, were observed in the alloxan diabetic rats and the decrease in amylase concentration was recovered by insulin treatment. Based on these findings, it is concluded that the change in amylase concentration during the starvation period may be a result of a decrease in plasma insulin concentration.

Exocrine pancreatic substitution: facts and controversies.

The effect on intraluminal postprandial concentrations of different pancreatic enzymes and on fat absorption were studied in 35 patients with advanced chronic pancreatitis with pancreatic insufficiency. Different regimes were studied: commercial Pankreatin (III) alone or in combination with Cimetidine, Pancrease, dispensed in microspheres, and commercial Pankreatin III compared to an equivalent uncoated preparation (Pankreatin I). Pankreatin induced significant increase in the intestinal concentration of amylase, lipase, and trypsin. Pretreatment with Cimetidine did not increase the enzyme concentrations further. The amount of enzymes in Pancrease capsules are rather small, no effect on concentrations of enzymes could be detected but treatment with Pancrease decreased significantly the fat excretion in faeces. The uncoated Pankreatin I induced a significantly higher increase in enzyme concentrations in the intestine compared to Pankreatin III but the overall effect tested on faecal fat excretion was identical with the two preparations. The results indicate that the estimation of concentration of enzyme at one level of the small intestine without and with enzyme substitution not necessarily gives information on the therapeutical effect of the enzymes.

Endoscopic manometry of the sphincter of Oddi and pancreatic duct in chronic pancreatitis.

Pancreatic duct pressure was studied by endoscopic manometry in 12 patients with chronic pancreatitis and in 9 patients with a normal pancreas (suspected biliary dyskinesia). To study the effect of increased intraduodenal concentration of pancreatic enzymes, the duct pressure was measured before and after intraduodenal enzyme infusion. The mean pancreatic duct pressure was 12 (range, 6-25) mm Hg and 18 (range, 6-38) mm Hg in the pancreatitis and 'control' groups, respectively. The occasional patient in each group who had a high duct pressure also had an elevated sphincter of Oddi pressure. A significant correlation between the two pressures was found in both groups of patients. During intraduodenal infusion of pancreatic enzymes a decrease of the pancreatic duct pressure occurred in only two patients. We conclude that an increased pancreatic duct pressure is not a frequent finding in chronic pancreatitis. An elevation of the duct pressure can also be found in patients without pancreatitis. The sphincter of Oddi pressure appears to be more important for the pancreatic duct pressure than the severity of the pancreatitis. Intraduodenal infusion of enzymes, as done in our study, had an inconsistent effect on the pancreatic duct pressure.

Ventromedial and dorsomedial hypothalamic syndromes in the weanling rat: Is the “center” concept really outmoded?

This report juxtaposes findings from weanling rats with precise lesions in the Ventromedial (VMNL rats) to data of weanling rats with lesions in the dorsomedial (DMNL) hypothalamic nuclei. Despite the proximity of the two nuclei their destruction produces opposite effects in most cases but similar responses in other parameters. Absolute and relative food intake are normal in VMNL rats yet they become obese in the face of normal body weight gains. DMNL rats show both reduced absolute food intake and body weight but normal relative food intake and body composition. Both VMNL and DMNL cause reduced linear growth and running wheel activity. DMNL rats defend their lower body weight set point against various challenges and maintain normal body composition. Organ growth in both absolute and relative terms is reduced in VMNL rats. In DMNL rats relative organ growth is normal. Pancreatic growth, protein/pancreas and content and concentrations of several pancreatic enzymes are normal in DMNL but reduced in VMNL rats. Mean 24-hour plasma growth hormone (GH) and corticosterone (B) levels are reduced and insulin levels are greatly elevated in VMNL rats; prolactin (PRL) levels are normal. In DMNL rats. GH, B, insulin and somatomedin activity are normal but PRL is elevated. Circadian rhythms of GH, insulin and triiodothyronine are normal in DMNL rats but B levels are disrupted, as they are in VMNL rats. Glucose incorporation and oxidation in adipose tissue of VMNL rats are enhanced in VMNL rats but normal in DMNL rats. Gluconeogenesis in VMNL rats is enhanced as early as 4 hours post-operatively; in DMNL rats it is normal at this time and several weeks thereafter. Basal lipolysis in epididymal fat pads is elevated in both VMNL and DMNL rats but epinephrine-stimulated lipolysis is elevated in VMNL and decreased in DMNL rats. Both VMNL and DMNL rats show normal basal and epinephrine-stimulated lipolysis in interscapular brown adipose tissue. Several hepatic enzymes are normal in DMNL and depressed in VMNL rats. The above data suggest that the DMN and its circuitry are part of an “organismic” set point system with a “true” body weight and not fat set point, as seems to be the case in the VMNL rat.

Combined effect of chronic bombesin and secretin or cholecystokinin on the rat pancreas

This work investigates the pancreatico-trophic action of bombesin, a peptide stimulating pancreatic secretion in vivo and in vitro and examines whether this effect is altered by CCK or secretin. Rats were injected three times daily for 5 days either with saline, bombesin (1 or 10 μg/kg), CCK (20 I.D.U. kg), secretin (20 C.U./kg) or a combination of bombesin and CCK or secretin. Bombesin alone induced growth of the pancreas beginning with the dose of 10 μg/kg. This growth was characterized by an increase of pancreatic weight, its protein, RNA and enzyme content, but not of its DNA content. The ratios of the three former parameters to DNA increased, suggesting cellular hypertrophy. Cholecystokinin alone exhibited a similar trophic action on the pancreas as bombesin. Secretin alone had no effect on pancreatic size and composition. Cholecystokinin and secretin did not modify the pancreatico-trophic response of bombesin. These findings suggest that bombesin, administered for 5 days in the rat, induces pancreatic growth due to cellular hypertrophy. Cholecystokinin has the same effect. However the mode of action, at the cellular level, of bombesin appears to be different from that of cholecystokinin.

Trophic effect of bombesin on the rat pancreas: Is it mediated by the release of gastrin or cholecystokinin?

This work investigates the effect, on the rat pancreas, of a chronic administration of bombesin in function of the dose and duration of treatment and examines whether this effect may be mediated by the release of endogenous gastrin or cholecystokinin. Bombesin, administered three times daily for 5 or 15 days, induced a marked increase in pancreatic weight, its protein, RNA and enzyme contents with the dose of 10 μg/kg body weight: the ratios of pancreatic weight, protein and RNA contents to DNA contents increased significantly after a 5 day treatment, suggesting cellular hypertrophy. Pancreatic DNA content was markedly enhanced after a 15 day treatment, suggesting cellular hyperplasia. Antrectomy decreased plasma gastrin levels, but did not alter the pancreatico-trophic action of a 10 μg/kg bombesin treatment for 5 days. Proglumide, an inhibitor of cholecystokinin and gastrin receptors in the pancreas, did not affect the growth of the pancreas induced by a 10 μg/kg bombesin treatment for 5 days. It is concluded that chronic bombesin induces, in the rat pancreas, cellular hypertrophy or hyperplasia depending on the duration of treatment. Pancreatic hypertrophy is not mediated by the release of endogenous gastrin or cholecystokinin.

Toxic Products in Hemorrhagic Ascitic Fluid Generated during Experimental Acute Hemorrhagic Pancreatitis in Dogs and a Treatment Which Reduces Their Effect

Toxic substances produced in hemorrhagic ascitic fluid during experimental hemorrhagic pancreatitis in dogs were investigated. An average of 394 ml of ascitic fluid was produced within 5 h after the induction of acute pancreatitis by intraductal injection of a mixture of autologous bile and trypsin. Hemorrhagic ascitic fluid was collected under sterile conditions, which was confirmed by aerobic and anaerobic culture and a Limulus test. The sterile fluid was injected intraperitoneally into mice in doses of 2 and 3 ml, and the mortality rate 72 h after injection was 66.0 and 88.4%, respectively. It contained high concentrations of pancreatic enzymes, including trypsin and esterase activity, as well as bradykinin, histamine and prostaglandin. Autopsy and histological examination of mice revealed shock with lung damage. The results suggest that hemorrhagic ascitic fluid produced in pancreatitis may be an important factor for early deaths in acute pancreatitis. When a new synthetic antiprotease (nafamstat mesilate) in a dosage of 0.2 mg was mixed with 1 ml of ascitic fluid, trypsin was not detectable, and bradykinin was reduced 1.0 ng/ml from 8.0 ng/ml, while esterase activity decreased to one tenth of its previous activity. The mortality following injection of the solution decreased to 26.7 and 80.6%, respectively. These results indicate that peritoneal lavage with a solution containing antiprotease may be an effective treatment for hemorrhagic acute pancreatitis.

Changes in content and secretion of pancreatic enzymes in the obese Zucker rat.

The contents of three major digestive enzymes (amylase, lipase and chymotrypsinogen) were measured in the obese Zucker rat. Only minimal changes were found in 7-week-old rats, but in adult obese rats (14-16 weeks) the amylase content was decreased by 50%, whereas the lipase and chymotrypsinogen contents were increased by 45% and 20%, respectively, compared with lean controls. Abnormalities of enzyme secretion were also found. Since the changes observed in enzyme proportions in adult obese Zucker rats are qualitatively similar to those observed in insulinopenic diabetes and other states associated with decreased glucose metabolism, it is speculated that the abnormalities found in the obese Zucker rat may be due to decreased glucose metabolism in the exocrine tissue consequent to insulin resistance.