Pancreatic Lipase Concentrations Research Articles

Gastric inhibitory polypeptide stimulates pancreatic lipase and colipase synthesis in rats.

Effects of short-term infusion and long-term injection of gastric inhibitory polypeptide (GIP) on changes in pancreatic lipase and colipase contents in rats were studied, and mRNAs encoding for lipase and colipase were determined by Northern blot hybridization with specific cDNA probes. GIP infused at a dose of 3 micrograms/h for 24 h significantly increased the pancreatic lipase content by 34% (P less than 0.05) but had no significant effect on colipase and amylase contents. No change in mRNAs encoding for these proteins was found after infusion of GIP for 24 h. Injection of GIP (5-60 micrograms/kg) three times a day for 5 days dose dependently increased the contents of lipase and colipase, with the increase in colipase being more prominent. Injection of GIP for 5 days at a dose of 30 micrograms.kg-1.day-1 increased colipase and lipase contents by 52 and 25%, and their corresponding mRNAs by 60 and 160%, respectively. The amylase mRNA was not changed by injection of GIP. It is concluded that GIP has a specific stimulatory effect on the synthesis of pancreatic lipase and colipase at both pretranslational and translational levels.

Beneficial effects of the synthetic trypsin inhibitor camostate in cerulein-induced acute pancreatitis in rats

The therapeutic effect and the mechanism of action of the synthetic trypsin inhibitor camostate were studied in a rat model of acute interstitial pancreatitis induced by four subcutaneous injections of 20 micrograms/kg body weight of cerulein at hourly intervals. Rats with acute pancreatitis were given either 100 mg/kg body weight camostate or volume- and pH-adjusted water via an orogastric tube 30 min after the last cerulein injection. The elevation of serum amylase activity was significantly reduced by camostate treatment and the peak value was seen 1 hr earlier than that observed in the rats that did not receive camostate. Camostate also inhibited the reduction in pancreatic content of lipase and amylase seen during experimental pancreatitis. These effects were accompanied by alleviation of the histologic signs of acute pancreatitis such as cellular infiltration and acinar cell vacuolization. After oral administration, camostate and its metabolite were absorbed from the intestine and were detectable in plasma for more than 6 hr in concentrations high enough to have antiprotease activity. In addition, camostate in the duodenum was able to increase pancreatic juice flow and protein output and to stimulate endogenous secretin release. These results suggest that oral administration of camostate reduces the severity of cerulein-induced acute pancreatitis by releasing endogenous secretin and by its antiprotease activity.

Long-term effect of growth promoting conditions on the exocrine pancreas of rats

Pancreatic adaptation following prolonged exposition to growth promoting conditions (protease inhibitor feeding, B II subtotal gastrectomy, subtotal colectomy) was studied in rats. Fifty male Wistar rats were divided into 5 groups: controls (n = 10), sham-operated (n = 10), low dose protease inhibitor feeding (n = 10), B II subtotal gastrectomy (n = 10), and subtotal colectomy (n = 10). After 4 mo a significant increase in pancreatic wet wt and DNA content was observed in rats after protease inhibitor feeding (p less than 0.01), B II gastrectomy (p less than 0.01), and subtotal colectomy (p less than 0.05). Pancreatic total protein and lipase content were significantly increased in these three groups. Amylase and trypsin content increased after feeding the protease inhibitor (p less than 0.01) and following B II subtotal resection (p less than 0.01) but were unaffected after subtotal colectomy. Comparing the long-term effects (4 mo) with our previously published short-term data (4 wk) under the same experimental conditions, pancreatic trophism after 4 mo is less pronounced but characterized by a change in the enzyme composition with an increase in pancreatic lipase content.

A possible physiological function of pancreatic pro-colipase activation peptide in appetite regulation

Pancreatic pro-colipase activation peptide, a pentapeptide with the sequence VPDPR was found to significantly suppress food intake of 20 h fasted Sprague-Dawley rats in a dose-dependent way. A rat treated with pro-colipase-enriched pellets for 26 days showed decreased daily food intake and retarded growth, which were restored during a following period of regular feeding. Genetically obese Zucker rats (fa/fa) were found to contain a reduced content of pancreatic pro-colipase (60% reduction), whereas the pancreatic lipase content was normal. A physiological function of pancreatic pro-colipase activation peptide as an endogenous satiety signal is suggested.

Comparative effect of chronic bombesin, gastrin-releasing peptide and caerulein on the rat pancreas

This study was designed to compare, on a molar basis, the effect of chronic bombesin, gastrin-releasing peptide (GRP) and caerulein on pancreatic growth in the rat. These 3 peptides were administered s.c. 3 times daily for 4 days at the following concentrations: 0.036, 0.36, 3.6 and 7.2 nmol/kg of body weight. Bombesin and GRP induced pancreatic growth in a dose-dependent manner from 3.6 nmol/kg. This growth was characterized by an increase in pancreatic weight, its protein and RNA contents but not in DNA content suggesting cellular hypertrophy. Caerulein exerted a biphasic effect on pancreatic growth, inducing cellular hypertrophy at low doses since 0.36 nmol/kg and atrophy with the highest dose (7.2 nmol/kg). Bombesin and caerulein (until 3.6 nmol/kg) increased the pancreatic content in chymotrypsin more than in amylase. The 7.2 nmol/kg caerulein treatment depressed all enzyme activities while the same dose of GRP increased pancreatic lipase content. It is concluded that (1) bombesin and GRP are equipotent trophic factors for the pancreas; (2) caerulein is the most potent factor and exerts a biphasic effect on pancreatic growth; (3) pancreatic growth and synthesis and/or secretion of enzymes are not regulated through the same mechanism.

Assay of human pancreatic lipase in biological fluids using a non-competitive enzyme immunoassay

A sandwich enzyme immunoassay has been developed for human pancreatic lipase using polystyrene balls coated with specific IgG as the first antibody and peroxidase-labelled IgG as the second antibody. The detection limit was 0.5 μg/1. Good parallelism was observed with the curves obtained from standard lipase and lipase present in serum, pancreatic juice and duodenal contents, demonstrating that the assay may be used to measure the level of the protein in different biological fluids. Mean values of lipase in human sera were 12.3 ± 6.8 μg/1 in adults and 4.5 ± 2.7 in newborns. In all cases a good correlation was found in serum between the catalytic activity and the enzyme immunoassay. Lipase is detectable in amniotic fluids at the 18th week of pregnancy but at a very low level (0.95 ± 0.32 μg/1). In pancreatic juices, lipase concentration was 14.6% of the total protein content. A study on cystic fibrosis patients showed a poor correlation between blood pancreatic lipase concentration and fat malabsorption underlying the difficulty in assessing pancreatic function by the measurement of serum pancreatic enzymes. The use of the lipase assay in duodenal contents would permit better assessment of pancreatic function in patients presenting a severe or borderline defect in fat digestion and absorption.

Digestion and Absorption of Lipids in Poultry

Ingested lipids undergo intestinal emulsification, digestion, micellar solubilization, cell membrane permeation, intracellular esterification and incorporation into lipoproteins before release to the interstitial fluid. Bile salts secretion, essential to both emulsification and micelle formation in the intestine, has been found to be influenced by quantity and quality of dietary lipids and by other emulsifiers. Modifications of dietary lipid contents cause changes in pancreatic lipase content and secretion. Colipase secretion by the pancreas seems dependent on both lipid and protein intakes. Intracellular processes essential for lipid absorption increases in rate as lipid intake increases. Bile salts seem to play important roles as moderators of these processes. The ability to digest lipids is not fully developed in the newly hatched poultry. Addition of bile salts, lipase or phospholipids to chick diets improves the digestibility of animal fats, demonstrating that lipid digestive processes are not fully functional in the very young. Physiological studies support these indications. Lipase concentration in pancreatic tissue and intestinal contents of poultry increases severalfold during the first few weeks after hatch. Similar changes with age have been observed in bile salt secretion. The development in enterocytes of fatty acid-binding protein activity seems to parallel the development in lipase activity and bile salt secretion in poultry.

Method for accelerating the enzymatic hydrolysis of triacylglycerols

The basic possibility of lowering the concentration of pancreatic lipase in the hydrolysis of triacylglycerols (TAGs) deposited on a solid sorbent has been shown. The method of preparing the initial TAGs for hydrolysis that has been developed permits not only a 10-fold reduction in the amount of ligase but also the retention of a short time of hydrolysis with a high yield of reaction products.

Changes in pancreatic and intestinal enzyme activities following chenodeoxycholic acid feeding.

The effect of CDCA feeding on pancreatic and intestinal enzymes was studied. Mice were fed 0.5% w/w chenodeoxycholic acid in a normal diet. Pancreatic lipase concentration was significantly increased after 3 days on the CDCA diet, while amylase and trypsin concentrations were significantly higher at 23 days when compared with the controls. At 70 days there was a significant increase in the concentrations of amylase, trypsin, and lipase. Protein concentrations paralleled the rise in enzyme levels. Amylase and lipase, when measured as specific activities, were still higher than the controls at 70 days. Intestinal amylase levels did not change during the experiments, but intestinal alpha-glucosidase activity increased significantly in the CDCA-treated animals. The results are discussed in terms of their similarity with those reported to occur after feeding soybean trypsin inhibitor.

Intraluminal fat digestion in the chronic alcoholic.

Intraluminal fat digestion and absorption were evaluated in 15 chronic alcoholic and nine healthy volunteer males by aspiration of a standard meal from the jejunum. Intraluminal bile salts were present in normal concentrations and micellar solubilization of fatty acids and monoglycerides was within normal limits. Pancreatic lipase concentrations, however, were significantly lower in the alcoholic patients. As a consequence, hydrolysis of triglycerides was slower resulting in abnormally low concentrations of fatty acids and micellar lipids. Recovery of lipase production toward normal was demonstrated after four to six weeks by repeated intubation studies. Thus, in the chronic alcoholic insufficient production of pancreatic lipase seems to be responsible for the reversible abnormality in the intraluminal digestion of fat.

Action of neomycin on the intraluminal phase of lipid absorption.

Administration of a single 1 g dose of neomycin sulfate to five healthy subjects simultaneously with a test meal caused a marked increase in the proportion of fatty acid and bile acid in the ultracentrifuged deposit of aspirated intestinal contents. Labeled cholesterol was precipitated in a similar manner in two hypercholesterolemic patients. Neomycin had no effect on the pancreatic lipase concentration or on the pH of intestinal contents. These results confirm that the ability of neomycin to precipitate micellar lipids is due to interaction between the polybasic neomycin molecule and ionized fatty acids and bile acids. This mechanism provides an explanation for both the steatorrhea and hypocholesterolemia induced by this compound.

Lipolytic Activity of Human Gastric and Duodenal Juice Against Medium and Long Chain Triglycerides

The presence of lipase in gastric aspirates containing less than 3 % contamination with duodenal reflux (as determined by tests for bile acid) was demonstrated in all samples of apparently normal gastric juice from 73 subjects when assayed with a trioctanoin substrate emulsified in sodium taurodeoxycholate and buffered at p H 6. This enzyme, in contrast to lipase(s) in duodenal aspirate, was stable at p H 2, had a lower p H optimum, was rapidly inactivated by trypsin even in the presence of bile acid, and was moderately inhibited by added fatty acid. Like duodenal lipase(s), gastric lipase had greater activity against short chain than long chain triglycerides and was more active against the fatty acids in the 1 than in the 2 position of triglyceride. It had a much smaller apparent molecular weight (40,000 to 50,000) than duodenal lipase (>500,000) by gel filtration chromatography and had only moderate esterifying properties compared with duodenal lipase(s). Synthetic triglycerides were cleaved more slowly by gastric lipase than by pancreatic lipase in pancreatic fistula juice or duodenal content. Triglycerides of human milk particles were cleaved by gastric lipase and lipases present in duodenal content, but not by pancreatic fistula juice which lacked bile acid, suggesting that milk particle triglyceride is resistant to pancreatic lipase unless bile is present. In healthy adults, the concentration of gastric lipase in gastric contents was much less than that of pancreatic lipase in duodenal contents, and gastric lipase did not contribute significantly to the lipolytic activity of duodenal content after a test meal. Gastric lipase was significantly decreased in the gastric contents of 3 achlorhydric patients. Medium chain triglyceride was not cleaved by 16 hr of incubation at p H 1.8 or 1 hr of incubation at p H 1, suggesting that acid does not occur. Gastric lipase probably contributes to digestion of milk triglyceride in infants, as well as to hydrolysis of administered medium chain triglyceride, especially in children with decreased pancreatic lipase concentrations. Its limited activity against long chain triglyceride suggests that gastric lipase has little role in normal fat digestion in adults.

Species difference in pancreatic lipolytic and amylolytic enzymes

The pancreatic content of lecithinase A in man is approximately 10–20 times that in the dog. In contrast, the pancreatic content of lipase is one-half and of amylase one-sixth that of the dog. The rabbit is similar to man in its pancreatic amylase and lipase content, and to the dog in its lecithinase A content. In man the serum lecithinase A increases during acute pancreatitis, paralleling more or less the elevations in serum amylase and lipase. Though individual discrepancies are noted, all three enzymes increase roughly proportionately. During acute pancreatitis in the dog, the serum lecithinase A increases but slightly, in sharp contrast to the elevations in serum amylase and lipase which are greater than in man. Submitted on July 12, 1962