alpha-chymotrypsin and camostat

The role of small intestinal proteolytic activity in the regulation of upper gastrointestinal function in humans is poorly understood. The aim of this study was to determine the importance of proteolytic activity for protein- or amino acid-induced cholecystokinin release and pancreaticobiliary secretion.. In 9 healthy subjects, saline was perfused intraduodenally for 3 hours either with or without the synthetic protease inhibitor camostate. During the last hour, albumin or amino acids in the same molecular composition as albumin were also perfused.. Perfusion with camostate, in concentrations that abolished intraduodenal proteolytic activity, had no effect on unstimulated plasma cholecystokinin concentrations or gallbladder emptying, but markedly (P < 0.05) increased unstimulated pancreatic enzyme output. Perfusion with protein distinctly stimulated cholecystokinin release, gallbladder emptying, and pancreatic enzyme output (P < 0.05). Perfusion with camostate resulted in significantly lower protein-stimulated plasma cholecystokinin, gallbladder, and pancreatic enzyme responses (P < 0.05). Perfusion with amino acids also stimulated plasma cholecystokinin, gallbladder emptying, and pancreatic enzyme output (P < 0.05). Camostate did not inhibit these values.. This study shows that appropriate digestion of protein is required to stimulate plasma cholecystokinin release, gallbladder emptying, and pancreatic enzyme secretion in humans.

Topics: Adult; Albumins; Amino Acids; Amylases; Bilirubin; Cholecystokinin; Chymotrypsin; Duodenum; Endopeptidases; Esters; Female; Gabexate; Gallbladder; Gallbladder Emptying; Guanidines; Humans; Male; Pancreas; Pancreatic Polypeptide; Protease Inhibitors; Trypsin

Prostasin or human channel-activating protease 1 has been reported to play a critical role in the regulation of extracellular sodium ion transport via its activation of the epithelial cell sodium channel. Here, the structure of the extracellular portion of the membrane associated serine protease has been solved to high resolution in complex with a nonselective d-FFR chloromethyl ketone inhibitor, in an apo form, in a form where the apo crystal has been soaked with the covalent inhibitor camostat and in complex with the protein inhibitor aprotinin. It was also crystallized in the presence of the divalent cation Ca(+2). Comparison of the structures with each other and with other members of the trypsin-like serine protease family reveals unique structural features of prostasin and a large degree of conformational variation within specificity determining loops. Of particular interest is the S1 subsite loop which opens and closes in response to basic residues or divalent ions, directly binding Ca(+2) cations. This induced fit active site provides a new possible mode of regulation of trypsin-like proteases adapted in particular to extracellular regions with variable ionic concentrations such as the outer membrane layer of the epithelial cell.

Topics: Aprotinin; Calcium; Catalytic Domain; Cations, Divalent; Chymotrypsin; Crystallography, X-Ray; Esters; Gabexate; Guanidines; Humans; Protease Inhibitors; Protein Conformation; Sequence Alignment; Serine Endopeptidases; Substrate Specificity

This study was an investigation of the role of cholecystokinin (CCK) in the stimulatory action of cholestyramine on rat exocrine pancreas. Postprandial CCK release was significantly enhanced by acute administration of cholestyramine (12.7 +/- 1.8 vs 3.7 +/- 0.5 pmol/L in controls). Over four weeks, rats were fed either regular diet or diet containing 6% cholestyramine, and were treated with the specific CCK receptor antagonist L-364,718 (2 x 0.5 mg/kg body weight/day s.c.) or DMSO (vehicle for the antagonist). Cholestyramine significantly increased pancreatic weight and trypsin and chymotrypsin contents. L-364,718 abolished these effects. Concomitant administration of antagonist and cholestyramine elevated amylase content, compared to controls. CCK levels in fasted animals did not differ between the four groups. The effect of the same dose of L-364,718 on pancreatic enzyme depletion, induced by the protease inhibitor camostate, was studied in a control experiment. A single dose of camostate (200 mg/kg) caused a 44-68% decrease in enzyme content. L-364,718 reversed this effect for all enzymes. We conclude that CCK is the mediator of cholestyramine-induced pancreatic hypertrophy and increase in content of proteases. After long-term administration, the CCK receptor antagonist, in combination with cholestyramine revealed an agonistic effect on individual, pancreatic enzyme content.

Topics: Administration, Oral; Animals; Benzodiazepinones; Cholecystokinin; Cholestyramine Resin; Chymotrypsin; Devazepide; Dimethyl Sulfoxide; DNA; Dose-Response Relationship, Drug; Esters; Gabexate; Guanidines; Hypertrophy; Male; Organ Size; Pancreas; Rats; Rats, Inbred Strains; Receptors, Cholecystokinin; Time Factors; Trypsin; Trypsin Inhibitors

FUT-187, a newly synthesized compound, was studied on its inhibitory activities mainly on proteolytic enzymes, in comparison with those of FUT-175 and FOY-305, known serine protease inhibitors. FUT-187, as well as FUT-175 and FOY-305, had selective inhibitory activities on serine proteases including Clr, Cls, kallikrein, trypsin, plasmin and thrombin; its activities on these enzymes except Clr and pancreatic kallikrein were relatively lower than those of FUT-175 and FOY-305. Further studies were conducted focusing on complement-mediated reactions. In spite of its lower activities against Clr and Cls, inhibitions by FUT-187 on the complement-mediated hemolysis in vitro and in vivo were only a little weaker than or equivalent to that of FUT-175. FOY-305 was ineffective in these tests. Forssman shock in guinea pigs is known to be initiated by the activation of the complement system. The protective effect of intravenous or oral FUT-187 against this shock was definitely superior to that of FUT-175. Furthermore, FUT-187 inhibited changes accompanied with Forssman shock, such as increase in lung weight, the decrease in platelet counts and CH50, and histopathological changes. These results suggested that FUT-187 should be a more potent oral therapeutic agent than FUT-175 for various inflammatory diseases attributed to the excessive activation of the complement system followed by platelet aggregation.

Topics: Amylases; Animals; Chymotrypsin; Complement Inactivator Proteins; Complement Pathway, Classical; Esters; Fibrinolysin; Forssman Antigen; Gabexate; Guanidines; Guinea Pigs; Hyaluronoglucosaminidase; Imidazoles; Lipase; Male; Phospholipases A; Protease Inhibitors; Serine Endopeptidases; Trypsin Inhibitors

In the present study the effect of atropine on feedback regulation of pancreatic function was investigated in male rats. Orogastric tube feeding of a single dose of the protease inhibitor camostate (100 mg) caused a 6-fold increase in plasma CCK. This was accompanied by a 50% decrease in pancreatic enzyme content for up to 6 h. The effect of i.v. infusion of atropine (100 micrograms.kg-1.h-1) was studied 60 and 180 min after camostate feeding. Atropine completely abolished the decrease in enzyme content 180 min after camostate feeding. The stimulated CCK plasma levels were significantly lowered by the infusion of atropine 60 min, but not 180 min, after feeding of camostate. It is discussed that a cholinergic pathway mediates CCK release in the early phase of feedback regulation of pancreatic function.

Topics: Amylases; Animals; Atropine; Cholecystokinin; Chymotrypsin; Esters; Feedback; Gabexate; Guanidines; Lipase; Male; Pancreas; Pancreatic Juice; Protease Inhibitors; Rats; Rats, Inbred Strains; Time Factors; Trypsin

The effects of chronic oral treatment of rats with 400 mg/kg body weight camostat, a synthetic protease inhibitor, on weight gain and both pancreatic exocrine and endocrine secretion were studied and compared with pair-fed controls. Administration of camostat was found to result in a lower weight gain than in untreated rats fed ad libitum because of reduced food intake. The pancreas of treated rats showed hypertrophy and hyperplasia with significantly higher total contents of amylase, lipase, trypsinogen and chymotrypsinogen than that of pair-fed controls. The specific activity of lipase, trypsinogen and chymotrypsinogen remained unchanged but the specific activity of amylase was significantly lower than in pair-fed controls. Stimulation of pancreatic enzymes with CCK 8 in treated rats resulted in a greater output of proteases, no difference in secretion of lipase and a lower secretion of amylase than in pair-fed rats. Glucose-dependent insulin secretion was also significantly lower in camostat-treated rats than in controls. This effect could be reversed by gastric inhibitory polypeptide. After termination of treatment with camostat all enzymes were normalized within 14 d. Our results on the hypertrophied pancreas of rats suggest preferential synthesis and secretion of protease at the expense of amylase and diminished sensitivity of insulin to stimulation by glucose. All effects of camostat on the pancreas were reversible.

Topics: Amylases; Animals; Body Weight; Chromatography, High Pressure Liquid; Chymotrypsin; Esters; Gabexate; Guanidines; Insulin; Insulin Secretion; Islets of Langerhans; Lipase; Male; Pancreas; Protease Inhibitors; Rats; Rats, Inbred Strains; Trypsin

Application of a single dose of a new type of proteinase inhibitor camostate (FOY-305) via orogastric tube was used in rats to study the dose-response relationship of resulting pancreatic stimulation. Doses up to 10 mg/kg failed to elicit any response, while significant decrease in enzyme content and increase in serum CCK-levels were observed with doses ranging from 25 to 400 mg/kg. A single dose of 100 mg/kg was selected for a time-sequence analysis, which revealed a 60 to 70% depletion of enzyme stores persisting over 6 h and reverting to control levels by 12 h. Peak increases in serum CCK-levels (15-fold above the elevation observed after regular food intake) were found after 30 min and persisted as an 8- to 10-fold elevation for at least 3 h, then declined to control levels by 9 h. This prolonged endogenous hormone release and resulting pancreatic stimulation were also verified in a separate group of animals in which volume, protein, and enzyme output were measured after cannulation of the pancreatic duct. While volume secretion was not altered by feeding a single dose of 100 mg/kg FOY-305, protein and enzyme output increased 2- to 3-fold over a period of 7 h. Fine-structural analysis of the pancreas demonstrated efficient depletion of zymogen granules from acinar cells with all doses between 50 and 400 mg/kg, accompanied by the appearance of membrane material in the acinar lumina at 3 and 6 h. The same transient increase in the number of lysosomal bodies predominantly containing mitochondria with all doses above 50 mg/kg was interpreted as increased organelle turnover due to persisting hormonal stimulation.

Topics: Amylases; Animals; Cholecystokinin; Chymotrypsin; Esters; Gabexate; Golgi Apparatus; Guanidines; Kinetics; Lipase; Male; Microscopy, Electron; Pancreas; Protease Inhibitors; Rats; Rats, Inbred Strains; Trypsin

Topics: Amylases; Animals; Chickens; Cholecystokinin; Chymotrypsin; Ducks; Electric Stimulation; Esters; Gabexate; Guanidines; Male; Mink; Pancreas; Pancreatic Juice; Rabbits; Rats; Rats, Inbred Strains; Sheep; Swine; Trypsin; Trypsin Inhibitors; Vagus Nerve