Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:3.4.21.9 (enterokinase)
 675 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The release of enterokinase into human duodenal fluid was studied after intravenous injections of secretin and cholecystokinin-pancreozymin (CCK-PZ). In five control subjects there was a significant release of the enzyme after stimulation with either hormone. A similar release of enterokinase was observed after hormonal stimulation in three patients with total biliary obstruction and in four patients with pancreatic exocrine insufficiency. These results suggest that the hormone-mediated release of enterokinase is independent of bile salts and trypsin in man. This release of enterokinase into duodenal fluid may be physiologically important in protein digestion.
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PMID:The release of enterokinase following secretin and cholecystokinin-pancreozymin in man. 39 1

Enteropeptidase, trypsin, and chymotrypsin activity in basal and secretin-stimulated duodenal juice of 20 normal adult volunteers and 15 patients with gastrotestinal disease were determined. All enzyme concentrations showed skew distributions, but fluctuations in the secretin-stimulated juices were less pronouced than in the basal secretions. Secretin administration had no influence on the release of enteropeptidase from human duodenal mucosa, but resulted in a very small increase in secretion of pancreatic enzymes. Six out of seven patients with chronic alcoholic pancreatitis or cancer of the pancreas exhibited highly significant elevations of enteropeptidase in their basal as well as secretin-stimulated duodenal juice. It is suggested that raised luminal enteropeptidase activity may be the result of pancreatic insufficiency or elevated blood glucagon concentrations.
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PMID:Enteropeptidase levels in duodenal juice of normal subjects and patients with gastrointestinal disease. 66 28

Elastolytic activity of human duodenal contents was determined using the new chromogenic substrate succinyl-trialanine-p-nitroanilide (Suc-Ala3-NAp). The mean output values after pancreatic stimulation with pancreozymin and secretin were significantly higher in controls than in subjects with impairment of other secretory values (volume, bicarbonate, amylase, lipase). Agar gel electrophoresis and chromatography on DEAE-Sephadex revealed one to two fractions which differed in mobility (cathodic and anodic fraction), elution with different NaCl concentrations (0.15 M, cathodic fraction; 0.3 M, anodic fraction), and in behaviour towards synthetic and natural substrate (Suc-Ala3-NAp) and elastin-Congo Red). The cathodic fraction cleaved both substrates, whereas the anodic fraction cleaved only Suc-Ala3-NAp. After trypsin and enterokinase treatment the anodic fraction behaved as the cathodic fraction on DEAE-Sephadex chromatography. The molecular weights (Sephadex G-100) and the Michaelis constants (Suc-Ala3-NAp) of both fractions were identical (24 500; 0.45 X 10(-3) M). These fractions represent probably diffenent activation forms of pancreatic elastase.
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PMID:Elastolytic activity of human duodenal contents. 117 3

In a model of acute pancreatitis which requires that pancreatic enzymes leak from a permeable duct, we studied the role of intravenous enterokinase (195,000 daltons) in pancreatic enzyme activation. Anesthetized cats were given intravenous 16,16-dimethyl prostaglandin E2 to increase pancreatic blood flow and microvascular permeability. In some animals the permeability of the pancreatic duct was increased by perfusion of the duct with glycodeoxycholic acid (7.5 mM). Endogenous enzyme secretion was stimulated by IV CCK and secretin. Some cats also received enterokinase intravenously. Those animals that received PGE2, glycodeoxycholate, and enterokinase all developed pancreatitis. When any of these agents were not given the pancreases appeared normal. These findings were consistent with the hypothesis that intravenous enterokinase leaked from small pancreatic blood vessels into the pancreatic parenchyma and/or ducts where activation of pancreatic enzymes occurred. The development of pancreatitis appeared to require an increase in both microvascular and ductal permeability.
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PMID:Pancreatic duct and microvascular permeability to macromolecules. The relation to acute pancreatitis. 385 17

Duodenal fluids from control and cystic fibrosis (CF) patients were assayed for enterokinase (EK), trypsin and chymotrypsin activities. CF patients as a group were found to have higher basal EK activity in spite of low trypsin and chymotrypsin activities. In control patients, pancreozymin (CCK) injection led to increases in specific activities of trypsin and chymotrypsin and a decrease in EK but did not change the total EK activities. Secretin administration led to decreases in specific activities of trypsin and chymotrypsin compared to post-CCK levels. The total EK activities were greatly increased following secretin administration. Thus, secretin may have direct influence on the release of EK into the duodenum. CCK and secretin have no effect on the specific activities of trypsin, chymotrypsin and EK in CF patients. EK release in CF patients is either constitutive and therefore not affected by CCK and secretin or it has been fully induced by the low trypsin content and becomes unresponsive to further hormonal stimulation.
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PMID:Effect of pancreozymin and secretin on intraluminal enterokinase, trypsin, and chymotrypsin activities of cystic fibrosis and control children. 704 59

Enterokinase is a glycoprotein and is now designated enteropeptidase (E.C.3.4.4.8.). It is present in the duodenal and jejunal mucosa. Pancreatic proteolytic enzymes are secreted as proenzymes. Enterokinase converts trypsinogen to trypsin in the duodenal lumen. Duodenopancreatic reflux of duodenal enterokinase may be important in the pathogenesis of experimental and clinical acute pancreatitis. Congenital enterokinase deficiency is a distinct clinical entity characterized by diarrhea, failure to thrive, hypoproteinemia, and edema. Acquired enterokinase deficiency may occur in some diffuse small bowel diseases. Steatorrhea of celiac spruce may be due partly to the fact that deficiency of secretin and cholecystokinin may interfere with the action of enterokinase. The interrelationship between secretin, cholecystokinin, enterokinase, and bile salts is not completely understood.
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PMID:Enterokinase. 820 33

This review provides some aspects on the physiology of stimulation and inhibition of pancreatic digestive enzyme secretion and the pathophysiology of pancreatic acinar cell function leading to pancreatitis. Cholecystokinin (CCK) stimulates both directly via CCK-A receptors on acinar cells and indirectly via CCK-B receptors on nerves, followed by acetylcholine release, pancreatic enzyme secretion. It is still not known whether CCK-A receptors exist in human acinar cells, in contrast to acinar cells of rodents where CCK-A receptors have been well described. CCK has numerous actions both in the periphery and in the central nervous systems. CCK inhibits gastric motility and regulates satiety. Another major function of CCK is stimulation of gallbladder contraction. This function enables that bile acids act simultaneously with pancreatic lipolytic enzymes. Secretin is a major stimulator of bicarbonate secretion. Trypsinogen is activated by the gut mucosal enzyme enterokinase. The other pancreatic proenzymes are activated by trypsin. Termination of enzyme secretion may be regulated by negative feedback mechanisms via destruction of CCK-releasing peptides by trypsin. Furthermore, the ileum may act as a brake by release of inhibitory hormones such as PYY and somatostatin. In the pathophysiology of acute pancreatitis, fusion of zymogen granules with lysosomes leading to intracellular activation of trypsinogen is regarded as an initiation step. This activation of trypsinogen may be caused by the lysosomal enzyme cathepsin B. However, autoactivation of trypsinogen itself may be a possibility in pathogenesis. Autoactivation is enhanced in certain mutations of trypsinogen. Furthermore, an imbalance of protease inhibitors and active proteases may be involved. The role of pancreatic lipolytic enzymes, the role of bicarbonate secretion, and toxic Ca(2+) signals by excessive liberation from the endoplasmic reticulum have to be discussed in the pathogenesis of acute pancreatitis.
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PMID:New advances in cell physiology and pathophysiology of the exocrine pancreas. 2152 56