Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P61278 (somatostatin)
 22,083 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Somatostatin (SST) is used in the treatment of acute pancreatitis (AP) to inhibit pancreatic exocrine secretion, which represents one of the goals of medical treatment in this disease. Its therapeutic efficacy, however, is poor. One hypothesis, which has not yet been investigated, is that i.v. SST might be broken down by blood proteolytic enzymes. In order to evaluate the structural integrity and biological activity of infused SST, somatostatin-like immunoreactivity (SLI) and levels of pancreatic enzymes were monitored in the blood stream during the infusion of SST-14 (3,5 micrograms/kg/h for 48 h) in eight patients with severe acute pancreatitis. SLI was measured by both radioimmunoassay (RIA) and high-pressure liquid chromatography (HPLC). The results indicate that SLI levels increase promptly after the beginning of infusion, with a slower increase between 6 and 36 h, and a rapid increase again at 48 h. HPLC analysis shows a single peak of SLI with the same retention time as standard SST-14. Total amylase, lipase, and trypsinogen significantly decreased compared with pretreatment values (48, 63.1, and 77.4%, respectively) after 24 h of SST infusion, while a decrease in elastase 1 (62.6%) was observed later at 48 h. These results indicate that in severe AP, somatostatin recovered in plasma retains its biological activity: it inhibits pancreatic circulating enzymes, an action not influenced by breakdown of the peptide, as demonstrated by HPLC of the SLI measured in plasma.
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PMID:Somatostatin infused during acute pancreatitis retains its biological activity. 257 57

Since endogenous cholecystokinin (CCK) is released after oral administration of camostate, it has been suggested that camostate-induced pancreatic growth is mediated via circulating CCK. To test this concept, we investigated the effects of three potentially inhibitory substances on rat pancreatic hypertrophy caused by feeding of camostate over 2 weeks: (1) L-364,718, the novel specific highly potent nonpeptide CCK receptor antagonist, (2) octreotide (SMS 201-995), a potent long-lasting somatostatin analogue and (3) pancreastatin (33-49), the biologically active C-terminal fragment of the novel gastrointestinal peptide pancreastatin. Camostate feeding (200 mg/kg) once daily for 14 days induced a significant increase in pancreatic weight, total protein, trypsinogen and polyamine levels, whereas total amylase content was substantially diminished. Simultaneous oral or subcutaneous treatment with L-364,718 (0.3 mg/kg twice daily) completely suppressed all trophic effects of camostate. Octreotide (25 micrograms/kg twice daily s.c.) and pancreastatin (33-49) (10 micrograms/kg twice daily s.c.) did not change any trophic parameter. In case of octreotide it could be shown that two daily injections only partially suppressed elevated CCK levels. Pancreatic DNA and putrescine levels were slightly reduced in rats receiving the CCK antagonist alone. These results demonstrate that camostate-induced pancreatic hypertrophy in rats is caused by the release of endogenous CCK which may contribute to the maintenance of normal pancreatic DNA and putrescine concentrations.
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PMID:Influence of CCK antagonist L-364,718, pancreastatin (33-49) and a somatostatin analogue on camostate-induced rat pancreatic hypertrophy. 261 49

The current study examines the effects of bombesin on gastrointestinal and pancreatic growth in suckling rats. During a period of 6 days, 7-day-old rats were injected twice daily with bombesin tetradecapeptide (20 micrograms/kg) in hydrolyzed gelatin or with gelatin alone. At the end of bombesin treatment, the weights of stomach, intestine, and pancreas; the heights of fundic and antral mucosae; and the density of parietal cells were significantly increased over control values. The gastrin cell population also tended to be augmented. The surface of glandular stomach, the duodenal mucosal height, and the somatostatin cell population were not modified as compared to controls. Electron morphometric analysis indicates that the increase in pancreatic weight under bombesin treatment was partly due to hypertrophy of acinar cells. This was confirmed by biochemical data that also showed that hypertrophy was associated with hyperplasia. Storage of secretory granules in acinar cells of the neonate rat pancreas under bombesin treatment seemed probable. Chymotrypsinogen and trypsinogen pancreatic contents were greatly augmented; lipase and colipase contents were not affected, whereas the amylase content tended to decrease. All these findings suggest that bombesin might be a general trophic factor for the neonatal digestive system in the rat. The mechanism of its action, however, remains to be determined.
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PMID:Stimulating effect of bombesin on the growth of gastrointestinal tract and pancreas in suckling rats. 369 11

Chronic pancreatitis should be considered in all patients with unexplained abdominal pain. The importance of small duct disease without obvious radiographic abnormalities is an important new concept. Diagnostic evaluation should begin with simple, non-invasive, inexpensive tests (serum trypsinogen) to be followed by more complicated testing (hormone stimulation test) if needed. Enteric-coated pancreatic enzymes are the drugs of choice for treating steatorrhea, while conventional non-enteric coated enzymes are preferred for managing pain. The somatostatin analogue octreotide may become an important therapy for treating abdominal pain unresponsive to pancreatic enzyme therapy. Endoscopic approaches to the treatment of chronic pancreatitis are experimental and may cause damage to the pancreas. Surgical ductal decompression is appropriate in selected patients.
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PMID:Medical management of chronic pancreatitis. 777 9

We demonstrated previously that pancreatic secretion of individual enzymes is specifically regulated (1). In the present study, we investigated and defined contributing roles of cholinergic and cholecystokinin tones to the specific regulation of rat pancreatic secretion of digestive enzymes. Animals were provided with pancreatic, biliary, duodenal, and jugular vein cannulas allowing separate drainage of bile and pure pancreatic juice, as well as intravenous infusions of MK329 or atropine sulfate along with SMS 201-995 (SMS). Rats kept in restraint cages were divided into four groups. The first rat group was infused with 5 micrograms kg-1 h-1 SMS alone; the second group was infused with a mixture of SMS and MK329 (5 micrograms kg-1 h-1:0.5 mg kg-1 h-1); the third group received a mixture of SMS and atropine (5 micrograms kg-1 h-1); and rats in the fourth group were administrated a mixture of SMS, MK329, and atropine (5 micrograms kg-1 h-1:0.5 mg kg-1:100 micrograms kg-1 h-1). Food, but not water, was denied rats 10 h before the experiment and throughout the 6-h experimental period. During the experiment, pancreatic juice was continuously collected every 15 min from each rat, and a 15-microliter aliquot of the pancreatic juice sample was removed for total protein, amylase, lipase, trypsinogen, chymotrypsinogen, and proelastase assays. Pancreatic juice previously collected from a donor rat was mixed with the fresh bile and the mixture was recirculated into the duodenum. The secretory patterns over the 6-h experimental period showed that during the first hour of drug infusion, MK329 alone did not alter the SMS-induced inhibitory process of total protein and amylase, trypsinogen, and proelastase secretion, and there was no marked change in total protein and enzyme outputs. Adding atropine to SMS did not alter the secretory pattern during the first hour of drug infusion, but a significantly greater decrease in protein and enzymes outputs occurred. Correlations between paired enzyme outputs greatly increased with SMS alone, but some changed when either MK329 or atropine was infused along with SMS. When all drugs were infused together, enzyme outputs became strongly correlated. These results suggest that under fasting conditions, somatostatin and atropine can neutralize basal pancreatic enzyme outputs, leading to a constitutive type of secretion characterized by parallel secretion of the digestive enzymes. Furthermore, it is proposed that under basal secretion conditions, acetylcholine and cholecystokinin reaching the pancreatic acinar cells may act to dissociate pancreatic secretion of individual digestive enzymes originating from heterogeneous secretory granules.
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PMID:Modulation of pancreatic secretion of individual digestive enzymes in octreotide (SMS 201-995)-infused rats. 898 7

Pancreatitis is rightly the most feared complication of endoscopic retrograde cholangiopancreatography (ERCP). Ten percent to 15% of cases of post-ERCP pancreatitis (PEP) are severe by clinical and radiologic criteria. Such cases carry significant morbidity and mortality and are responsible for the vast majority of ERCP-related deaths. The prediction and prevention of PEP have been of great interest to endoscopists since the introduction of ERCP 30 years ago. Prediction and diagnosis of PEP have become more accurate with the widespread availability of serum amylase estimation. A variety of cytokines (eg, interleukin -1, IL-6, and IL-8) and acute phase reactants (eg, C-reactive protein) are also elevated in the serum in acute pancreatitis, and these form the basis of evolving tests for PEP. Urine testing (for amylase) in acute pancreatitis is obsolete, but it may soon undergo a revival in the form of a rapid (3-minute) dipstick test for trypsinogen-2, a sensitive and specific test for this disease. The prevention of PEP takes multiple forms. The following steps are recommended for clinicians: 1) avoid ERCP when other, less invasive or noninvasive imaging tests can do the job (eg, CT or magnetic resonance imaging); 2) avoid high-risk (of PEP) procedures, such as needle-knife papillotomy, balloon dilation of the biliary sphincter, and pancreatic sphincterotomy, and take steps to reduce risk when these procedures are unavoidable; 3) ensure that those who perform ERCP have adequate training and experience; and 4) consider pharmacologic intervention. Despite a depressing catalog of drug interventions that have failed over the years (eg, antihistamines, anticholinergics, and corticosteroids), three agents have recently shown promise: somatostatin; its octapeptide analogue, octreotide; and gabexate mesylate, a protease inhibitor.
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PMID:Predicting and preventing post-ERCP pancreatitis. 1190 Jun 75

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

Cells of the pancreatic islets produce several molecules including insulin (beta cells), glucagon (alpha cells), somatostatin (delta cells), pancreatic polypeptide (PP cells), ghrelin (epsilon cells), serotonin (enterochromaffin cells), gastrin (G cells) and small granules of unknown content secreted by the P/D1 cells. Secretion mechanism of some of these molecules is still poorly understood. However, Cathepsin L is shown to regulate insulin exocytosis in beta cells and activate the trypsinogen produced by the pancreatic serous acini cells into trypsin. The structure of the propeptide region of Cathepsin L is homologous to Cytotoxic T-lymphocyte antigen-2 alpha (CTLA-2 alpha) which is also shown to exhibit selective inhibitory activities against Cathepsin L. It was thought that if CTLA-2 alpha was expressed in the pancreas; then, it would be an important regulator of protease activation and insulin secretion. The purpose of this study was, therefore, to examine by immunohistochemistry the cellular localization and distribution pattern of CTLA-2 alpha in the pancreas. Results showed that strong immunoreactivity was specifically detected in the pancreatic islets (endocrine pancreas) but not in the exocrine pancreas and pancreatic stroma. Immunostaining was further performed to investigate more on localization of Cathepsin L in the pancreas. Strong immunoreactivity for Cathepsin L was detected in the pancreatic islets, serous cells and the pancreas duct system. These findings suggest that CTLA-2 alpha may be involved in the proteolytic processing and secretion of insulin through regulation of Cathepsin L and that the regulated inhibition of Cathepsin L may have therapeutic potential for type 1 diabetes.
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PMID:Immunoreactivity of cytotoxic T-lymphocyte antigen 2 alpha in mouse pancreatic islet cells. 3205 62