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

In 4 conscious dogs with gastric fistulas the somatostatin responses to a meal were measured and compared to the responses seen after i.v. infusion of atropine sulfate (20 and 50 micrograms.kg-1.h-1) or cimetidine (8 mg.kg-1.h-1). The experiments were repeated after truncal vagotomy. The somatostatin responses to bombesin (0.5 micrograms.kg-1.h-1) were also measured before and after vagotomy. Vagotomy decreased basal and postprandial somatostatin levels and reduced the somatostatin responses to feeding during the first 30-min period following the ingestion of the meal but not during subsequent periods. Bombesin-induced somatostatin release was increased after vagotomy. Atropine decreased the somatostatin responses to the meal before and after vagotomy. Cimetidine had no significant effect. These studies suggest that, in conscious dogs, somatostatin released into the circulation is partly under vagal control and that, as for gastrin release, vagal pathways for stimulation and inhibition are present. Our studies also suggest that cholinergic mechanisms are involved in the control of postprandial somatostatin release.
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PMID:Effect of vagotomy and atropine on plasma somatostatin response to a meal in conscious dogs. 289 34

Neurotensin (NT) differentially altered ethanol-induced anesthesia as measured by duration of loss of righting response or by blood ethanol levels producing loss of righting response in mice (LS and SS) which were selectively bred for differences in response to ethanol. At doses of 5-500 ng i.c.v., NT increased ethanol sensitivity in SS mice, but not in LS mice, as measured by blood ethanol concentrations at loss of righting response. At higher doses, 0.5-10 micrograms i.c.v., NT enhanced the sensitivity of both SS and LS mice to ethanol-induced anesthesia. The hypothermic effect of ethanol determined at loss of righting response was not altered in either LS or SS mice at low doses of NT, but at higher doses NT enhanced ethanol-induced hypothermia in both lines of mice. The altered anesthetic sensitivity was specific for ethanol in that NT did not alter pentobarbital-induced sleep time in either LS or SS mice and halothane anesthesia was altered slightly only in LS mice. NT analogues, N-acetyl-NT8-13, and [D-Trp11]-NT but not NT1-8 enhanced the anesthetic action of ethanol in SS mice. Bombesin, cholecystokinin sulfate, substance P, [D-Trp8, D-Cys14]-somatostatin and corticotropin releasing hormone (CRF) were not effective in enhancing ethanol-induced anesthesia in LS or SS mice. CRF appeared to decrease ethanol sensitivity in LS but not in SS mice. Beta-Endorphin (beta-END) markedly increased the ethanol sensitivity of SS and to a lesser extent of LS mice at relatively high doses, e.g. 0.5-1.0 micrograms i.c.v. The results of the present study indicate that differences in brain sensitivity of LS and SS mice to ethanol may be mediated by genetic differences in NT systems. Likewise, NT, and probably beta-endorphin, may interact with other neurochemical processes that are involved in the mechanism of ethanol-induced anesthesia and that differ genetically in LS and SS mice.
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PMID:Neurotensin selectively alters ethanol-induced anesthesia in LS/Ibg and SS/Ibg lines of mice. 294 96

The functional and biochemical characterization of rat bone marrow derived mast cells (RBMMC) confirms both species-related differences between rat and mouse bone marrow-derived mast cells (MBMMC) as well as mast cell heterogeneity in a single species. Such RBMMC have the staining characteristics of mucosal mast cells and contain the mucosal mast cell protease. The RBMMC release the preformed granule mediator beta-hexosaminidase both in response to immunologic stimulation with 200 ng Ag (net release 15.8 +/- 3.8%) and in response to 1 microM calcium ionophore A23187 (net release 21.8 +/- 6.8%). However, compound 48/80, substance P, and somatostatin did not induce mast cell degranulation. In experiments with optimal beta-hexosaminidase release, the RBMMC generated similar quantities of the newly formed arachidonic acid metabolites leukotriene C4 and PGD2 when stimulated with either Ag or calcium ionophore A23187. The RBMMC incorporate [35S]sulfate into proteoglycans consisting of 90% chondroitin sulfates and 10% heparin. The chondroitin sulfates were comprised of chondroitin 4 sulfate and chondroitin sulfate diB sulfated disaccharides in a ratio of 4/1. Although we show that RBMMC and MBMMC share a low histamine content, functional IgE receptors and unresponsiveness to cromolyn and selective secretagogues (compound 48/80, substance P, and somatostatin), we also provide evidence that RBMMC differ from MBMMC in their profile of newly generated mediators, preformed granule proteoglycan, and lack of proliferative response to mouse IL-3.
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PMID:Functional and biochemical characterization of rat bone marrow derived mast cells. 297 57

CRF stimulates the synthesis and secretion of proopiomelanocortin-derived peptides from AtT-20 mouse pituitary tumor cells. This study has shown that there is a specific binding site for CRF located on the plasma membrane of these cells. Both [125I]iodo-Tyr0CRF and noniodinated CRF (10(-11)-10(-7) M) stimulated, in a dose-dependent manner, the secretion of equimolar amounts of beta-endorphin-like immunoactivity from AtT-20 cells. Disuccinimidyl suberate, a cross-linking agent, was used to demonstrate specific binding of [125I]iodo-Tyr0CRF to plasma membranes from these cells. After cross-linking [125I] iodo-Tyr0CRF, the membrane proteins were solubilized with sodium dodecyl sulfate and electrophoresed on a 10% polyacrylamide gel. A single radioactively labeled band, corresponding to a mol wt of 66,000, was identified by autoradiography. [125I]Iodo-Tyr0CRF binding to these membranes was inhibited by 10(-7) M unlabeled CRF or an equimolar concentration of the CRF analog sauvagine. Similar concentrations (10(-7) M) of TRH, GnRH, insulin, [Arg8]vasopressin, somatostatin, and ACTH did not inhibit [125I]iodo-Tyr0CRF binding to the plasma membranes. Incubation of AtT-20 cells for 24 h in the presence of 10 nM dexamethasone reduced [125I]iodo-Tyr0CRF binding by 80% compared to that in untreated cells. Dexamethasone also inhibited the CRF-stimulated beta-endorphin-like immunoactivity secretory response. These data indicate that binding of CRF to a specific membrane protein is an integral component in the stimulation of AtT-20 cells by CRF.
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PMID:Identification of a corticotropin-releasing factor-binding protein in the plasma membrane of AtT-20 mouse pituitary tumor cells and its regulation by dexamethasone. 303 86

The effect of 15 defined neuropeptides on the mitogenic activation of lymphocytes from human thymus, guinea pig lymph nodes and rat spleen was investigated. Lymphocytes were incubated in the absence or presence of polyclonal T and B cell activators together with increasing doses of the neuropeptides, and harvested at 48 h of culture after pulse-labeling with 3H-thymidine to assess the DNA synthesis. A dose-related stimulatory effect on the spontaneous 3H-thymidine incorporation of human thymocytes was obtained with methionine-enkephalin (met-enk), motilin and neurotensin. Vasoactive intestinal polypeptide (VIP) and peptide HI (PHI) were inhibitory. A similar responsiveness was observed in cultures of phytohemagglutinin P (PHA)-activated human thymocytes. The low level of basal DNA synthesis of guinea pig lymph node cells was stimulated by VIP and inhibited by neuropeptide Y (NPY) and PHI. PHA-activated lymph node T lymphocytes were stimulated by neurotensin, bombesin and motilin, whereas NPY inhibited the thymidine uptake. The low rate of spontaneous DNA synthesis of rat spleen cells was increased in the presence of VIP. Met-enk stimulated both basal and dextran sulfate-activated splenic B cell proliferation, whereas PHI was inhibitory in both cases. The following peptides were found to be inactive in all the above assays: substance P, cholecystokinin-octapeptide, somatostatin, galanin, oxytocin, pentagastrin and gastrin-releasing peptide 1-27 and 14-27. Although the responses were generally of low magnitude and observed at high peptide concentrations, present study contributes to the understanding of possible mechanisms involved in interactions between the nervous and the immune system.
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PMID:Neuropeptide regulation of human thymocyte, guinea pig T lymphocyte and rat B lymphocyte mitogenesis. 349 94

Utilizing islet amyloid-laden pancreatic tissues from six diabetic cats, we demonstrated substantial immunoreactivity (peroxidase-antiperoxidase technique) of the islet amyloid with antiserum to a B chain-rich insulin fraction, but no reactivity with antisera to insulin, glucagon, or somatostatin. Islet amyloid was purified from two cats and a protein unique to the diabetic and islet amyloid-laden cats was separated by sodium dodecyl sulfate polyacrylamide gel electrophoresis. Immunoreactivity of this protein with antiserum to the B chain-rich insulin fraction was also shown by immunoblotting. Attempts to obtain the amino acid composition of the purified unique protein (represented by a single 25,000 dalton band on gel electrophoresis) were not successful because the amount of protein was too small. These results provide important additional evidence that an insulin-related protein is involved in the formation of islet amyloid. Our study also shows that the diabetic cat provides several advantages for the continued study of the etiopathogenic relationship of islet amyloid and diabetes mellitus.
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PMID:Feline insular amyloid: immunohistochemical and immunochemical evidence that the amyloid is insulin-related. 390 95

Using a radioimmunoassay with labeled synthetic tetradecapeptide somatostatin, a large amount of immunoreactive somatostatin was found in the principal pancreatic islet of the channel catfish (Ictalurus punctata). The purpose of these experiments was to isolate and characterize the somatostatin-like material. Extracts of islets were chromatographed on a Bio-Gel P-30 column, and over 90% of the immunoreactive somatostatin migrated with proteins at least twice the size of synthetic tetradecapeptide somatostatin. This fraction was further purified by ion-exchange chromatography on carboxymethyl-cellulose and DEAE-cellulose columns. Two peptides were obtained with identical immunoreactivity, which was approximately 25% that of the synthetic somatostatin. Each peptide was judged to be >95% pure by thin-layer electrophoresis, polyacrylamide gel electrophoresis at pH 8.9, and highpressure liquid chromatography. Further criteria of purity included amino-terminal analysis of fraction IV yielding only aspartic acid. A total of 1.3 mg of fraction II, and 3.8 mg of fraction IV somatostatin-like peptides were obtained from 10 g of fresh frozen islets. Characterization of the two peptides revealed both peptides slightly more acidic than synthetic tetradecapeptide somatostatin. Fraction II had an isoelectric point of 8.0-8.3, and fraction IV 8.3-9.0. Molecular weight estimation by sodium dodecyl sulfate-urea polyacrylamide gel electrophoresis revealed similar mobility of both peptides, between pancreatic polypeptide (mol wt 4,500) and glucagon (mol wt 3,500). The mobility was not altered by reduction, and was approximately twice the size of synthetic tetradecapeptide somatostatin (mol wt 1,800). This confirmed that the peptides were single polypeptide chains and not aggregates, or somatostatin bound to larger proteins. Molecular weight determination by gel filtration chromatography on Bio-Gel P-6 in 8 M urea gave an estimated mol wt of 3,700. Amino acid analysis of the two immunoreactive somatostatins indicated that they were very similar in composition. Both pancreatic somatostatins (1 muM) had full biological activity relative to synthetic somatostatin measured as inhibition of growth hormone release from rat anterior pituitary cells.
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PMID:Isolation and characterization of immunoreactive somatostatin from fish pancreatic islets. 610 73

The effect of cationic, anionic and nonionic detergents on the EPR spectrum of spin-labeled somatostatin has been studied. At detergent concentrations well above the critical micelle concentration, nonionic detergents do not alter the EPR spectrum. Sodium dodecyl sulfate markedly alters both the line height ratio and the hyperfine splitting constant, whilst dodecyltrimethylammonium bromide alters only slightly the hyperfine splitting constant and line height ratio. The somatostatin-sodium dodecyl sulfate complex appeared monodisperse by sedimentation equilibrium with about 17 g bound detergent per g peptide. Circular dichroic and difference spectra of the dodecyl sulfate-somatostatin complex show that the tryptophanyl residue is buried in a nonpolar environment and that the secondary and tertiary structure of the peptide is markedly altered. Sedimentation equilibrium studies suggest that two types of dodecyltrimethylammonium-somatostatin complex exist. One type resembles the dodecyl sulfate-peptide complex, whilst the other appears to include several peptide units with only about one gram bound detergent per gram peptide.
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PMID:Somatostatin-detergent interaction. 610 70

Messenger RNA from catfish pancreatic islets was translated in a wheat germ cell-free protein synthesizing system. A protein of 12,000 mol wt, preprosomatostatin, was identified by specific immunoprecipitaton with anti-catfish pancreatic somatostatin and sodium dodecyl sulfate (SDS)- polyacrylamide gel electrophoresis.
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PMID:Cell-mediated synthesis of somatostatin. 610 72

To evaluate the possible cholinergic control of islet hormone secretion, acetylcholine (10 microM) was perfused into the isolated chicken pancreas-duodenum, with perfusate concentrations of 2.8, 14, or 42 mM glucose. Prompt and significant stimulation of insulin, glucagon, and somatostatin secretion was seen when the glucose concentration was 14 mM, and this stimulation was blocked by preinfusion of atropine sulfate (50 microM). Similar stimulation of all three peptides was seen when the perfusate concentration of glucose was 42 mM. When the perfusate glucose concentration was 2.8 mM, the insulin response to acetylcholine was absent and the response by glucagon could not be discerned, perhaps because release was close to maximal. The somatostatin response, however, was only slightly diminished from that seen at higher glucose levels. The B cell response to acetycholine in the chicken was considerably greater than the weak responses seen to high glucose or arginine, suggesting a dominant role for cholinergic control of avian insulin secretion. In addition, the parasympathetic nervous system may also play a role in the secretory control of A- and D cells.
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PMID:Acetylcholine stimulates insulin, glucagon, and somatostatin release in the perfused chicken pancreas. 610 51


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