Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: 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)

Porcine vasoactive intestinal peptide stimulated adenosine 3':5'-monophosphate (cyclic AMP) production in rat intestinal epithelial cells. The stimulation was dependent on time and temperature and was potentiated by the phosphodiesterase inhibitor 3-isobutyl-1-methylxanthine. Under optimal conditions (at 15 degrees C, with 0.2 mM 3-isobutyl-1-methylaxanthine, at a cell concentration up to 18 microgram DNA/ml), the cyclic AMP production produced by vasoactive intestinal peptide was constant for 10 min and stopped after 15 min incubation, at either low (1 nM) or high (30 nM) concentration of the peptide. This plateau effect was demonstrated not to be due to an inactivation of vasoactive intestinal peptide in the medium nor to an alteration of receptors for the peptide. Cyclic AMP production was sensitive to a concentration as low as 0.1 nM vasoactive intestinal peptide. Maximal stimulation of cyclic AMP levels by vasoactive intestinal peptide was observed with 30 nM vasoactive intestinal peptide and represented an 11-fold increased above basal. The dorse-response curve was monophasic with a Km of 2.3 x 10(-9) M. No cooperative effects were detected by Hill analysis. The positive non-linear relationship observed between stimulation of cyclic AMP production and occupancy of binding site was not time-dependent as indicated by experiments performed after 15, 45 and 120 min incubation. Maximal and half-maximal responses were obtained at about 70% and 7% occupation of binding sites, respectively. Chicken vasoactive intestinal peptide and porcine secretin were agonists of porcine vasoactive intestinal peptide with a 6-times and a 120-times lower potency, respectively. Among secretin analogs that were found to have low affinity for vasoactive intestinal peptide binding sites, [4-alanine, 5-valine]secretin, that resembles vasoactive intestinal peptide at the first seven amino acids at the N-terminal end, was a partial agonist of vasoactive peptide at the first seven amino acids at the N-terminal end, was a partial agonist of vasoactive intestinal peptide and others failed to stimulate cyclic AMP production. Glucagon (10microM), gastric inhibitory peptide (0.1 microM), substance, P, neurotensin, octapeptide of cholecystokinin, bovine pancreatic polypeptide, human gastrin I with leucine at residue 15, Leu-enkephalinand somatostatin (1 microM) did not alter cyclicAMP levels. Non-peptide mediators such as dopamine, serotonin, acetylcholine and histamine, tested at 10 microM, were also ineffective. Prostaglandins E2, E1 and isoproterenol, tested at 10 microM, induced an increase of cyclic AMP levels above basal but were 9.5, 13.7 and 17.5 times less efficient than vasoactive intestinal peptide, respectively. Thus vasoactive intestinal peptide is a unique stimulus of cyclic AMP production in rat intestinal epithelial cells.
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PMID:Interaction of vasoactive intestinal peptide with isolated intestinal epithelial cells from rat. 2. Characterization and structural requirements of the stimulatory effect of vasoactive intestinal peptide on production of adenosine 3':5'-monophosphate. 8 68

A case of glucagonoma syndrome with necrolytic migratory erythema, glossitis, anemia, hyperglucagonemia and a malignant, pancreatic A-cell tumour in a 68-year-old male is described. Gel filtration of the highly elevated circulating glucagon immunoreactivity (2200 pg/ml) demonstrated 60% pancreatic glucagon and 30% "proglucagon". Metabolic studies before operation demonstrated suppression of the total plasma glucagon concentration on oral glucose tolerance test, unchanged total plasma glucagon concentration during intravenous glucose tolerance test and insulin-induced hypoglycemia. Administration of arginine was followed by a rise in both the pancreatic glucagon and the "proglucagon", whereas alanine increased only the pancreatic glucagon. The plasma somatostatin level was immeasurable preoperatively. Somatostatin infusion completely suppressed the release of the pancreatic glucagon but did not significantly affect the "proglucagon". After removal of the tumour the skin lesions disappeared and the total plasma glucagon values fell to normal levels (120 pg/ml). Also, other abnormal laboratory findings returned to normal, including the preoperatively observed renal glucosuria.
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PMID:Metabolic studies and glucagon gel filtration pattern before and after surgery in a case of glucagonoma syndrome. 21 26

Most of the somatostatin-like activity from pigeon pancreas was found to correspond to small species with an apparent molecular weight of 1500--2500. This species was isolated under conditions minimizing intermolecular interactions and protease activities. The isolated product was characterized by two somatostatin radioimmunoassays, a bioassay, endgroup determination, and amino acid analysis. The structure of the isolated compound was determined to be H-Ala-Gly-cyclo-(Cys-Lys-Asn-Phe-Phe-Trp-Lys-Thr-Phe-Thr-Ser-Cys)-OH. Additionally, small amounts of des-Ala1-somatostatin, a possible degradation product of pancreatic somatostatin, and a large somatostatin-like species with an apparent molecular weight of 11,000--12,500 were detected. It is concluded that the main somatostatin-like polypeptide isolated from pigeon pancreas is identical to the mammalian hypothalamic tetradecapeptide somatostatin.
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PMID:Isolation and characterization of somatostatin from pigeon pancreas. 28 81

These experiments have been designed to study the influence of alanine infusion of glucose dynamics in the dog and to further elucidate the role of pancreatic hormones in the interaction of alanine with glucose homeostasis. The primed constant infusion of glucose-2-t was used in order to quantitate the rates of glucose production by the liver (Ra) and glucose utilization (Rd). In a first group of experiments, the intravenous infusion of alanine at the rate of 2 mg./kg./min. produced a moderate enhancement of plasma insulin (IRI), while pancreatic glucagon (IRG) increased more consistently. This different pattern of IRI and IRG response caused the insulin/glucagon molar ratio to decline progressibely throughout the experiment. Both rates of glucose turnover increased significantly during alanine infusion. Since Ra rose more rapidly thanRd did initially, hyperglycemia developed. Later, glucose production slowly decreased and, in spite of the sustained hyperglucagonemia, reached levels very close to the baseline in the second part of the experiment. A significant direct correlation between Ra and IRG was found, while the changes in Ra correlated inversely with those in I/G molar ratio. In a second group of experiments, alanine was infused at the same dose together with 0.4 microng./kg./min. of cyclic somatostatin. In the first part of the infusion, IRG fell more than IRI did, so that I/G ratio increased. Later, IRI levels maintained at low values while IRG returned slowly to the baseline and consequently I/G ratio significantly decreased. Glucose production fell rapidly soon after the beginning of the infusion, and therefore hypoglycemia developed. Later, Ra increased progressively to levels above baseline and plasma glucose returned to the preinfusion levels. As in the the first group of experiments, a significant direct correlation between Ra and IRG and an inverse correlation between the changes in Ra and I/G ratio were observed. These experiments demonstrate that alanine infusion produces an acceleration of glucose turnover and that a clear interrelationship between the release of glucose by the liver and the mobilization of pancreatic hormones exists. Finally, the experiments with somatostatin indicate that hyperglucagonemia is one of the mechanisms underlying the stimulatory effect of alanine on glucose production.
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PMID:Studies on the mechanism underlying the influence of alanine infusion on glucose dynamics in the dog. 30 Mar 41

The regulation of hepatic glucose production by glucagon and insulin has been studied in the intact dog. An attempt has been made to evaluate the role of basal physiological concentrations of the hormones in the regulation of glycogenolysis and gluconeogenesis. Somatostatin was infused continuously into postabsorptive dogs to inhibit the secretion of both glucagon and insulin. Either or both hormones were then replaced intraportally by continuous infusion as desired. The main observations were as follows. (1) When both hormones were simultaneously replaced for periods up to 4.5h, plasma insulin and glucagon concentrations, total glucose output (glycogenolysis plus gluconeogenesis), glucose utilization and the plasma glucose concentration closely matched the same parameters in 0.9% NaCl-infused controls. (2) When glucagon alone was infused, thereby creating a selective insulin deficiency, glucose output (primarily glycogenolysis) rapidly increased by as much as threefold. Glycogenolytic glucose production then fell off progressively and returned to the control value within 4h. The gluconeogenic conversion of [14C]alanine and [14C]lactate into [14C]glucose was stimulated markedly and increased progressively throughout the test period. Glucagon therefore converted the liver from an organ largely dependent on glycogenolysis for glucose production to one heavily dependent on gluconeogenesis. The potent inhibitory effect of basal insulin on postabsorptive glucose output was also clearly apparent. (3) When insulin alone was infused, thereby creating a selective glucagon deficiency, glucose output (glycogenolysis) fell abruptly by about 30% and remained decreased. Gluconeogenesis also decreased (20%) after the selective removal of both insulin and glucagon, but it only remained suppressed for 1h. The low glucose output led to a modest fall in the blood glucose concentration. Thus glucagon plays an important role in maintaining basal glucose production. (4) When insulin was infused and the plasma glucose was kept at its control concentration by infusion of glucose in similar experiments to the above, the hepatic output of glucose fell by as much as 75%. This demonstrates the presence of a glucagon-independent metabolic reflex triggered by a low plasma glucose concentration, the purpose of which is to maintain glucose output at a rate capable of preventing castastrophic hypoglycaemia.
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PMID:Control of hepatic glucose output by glucagon and insulin in the intact dog. 37 68

Somatostatin was purified from anglerfish pancreatic islets using acetic acid extraction, gel filtration (Bio-Gel P-10), ion exchange chromatography (CM Bio-Gel A), and reversed phase high pressure liquid chromatography. The resulting peptide was characterized by RIA, bioassay, and determination of amino acid composition. Anglerfish islet somatostatin was found to possess an amino acid composition and immunological and biological activities equivalent to synthetic somatostatin. Sequence analyses revealed that the primary structure was H-Ala-Gly-cyclo-[Cys-Lys-Asn-Phe-Phe-Trp-Lys-Thr-Phe-Thr-Ser-Cys]-OH. These results demonstrate that anglerfish islet somatostatin has the same primary structure as somatostatin from all other sources characterized to date.
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PMID:Isolation and characterization of somatostatin from anglerfish pancreatic islet. 38 85

The effect of an iv load of individual amino acids (alanine, arginine, histidine, leucine, phenylalanine, and valine) on serum prolactin (Prl) and growth hormone (GH) concentrations was studied in healthy adult males (n = 5). A rise in both, Prl and GH with a maximal increment of 15.9 +/- 6.7 (SE) ng/ml, and 12.4 +/- 4.9 ng/ml above basal levels, respectively, (P less than 0.05) was observed after iv arginine. Following iv phenylalanine the mean peak level of Prl rose from 9.9 +/- 3.5 to 29.9 +/- 7.3 ng/ml (P less than 0.01), whereas GH concentration remained unchanged. Iv leucine however induced an immediate rise in GH, but not in serum Prl. Serum concentrations of both, Prl and GH, failed to increase upon the infusion of either alanine or histidine or valine. Additional somatostatin administration starting prior to amino acid infusion diminished the amino acid induced increase of both Prl and GH release.
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PMID:The influence of amino acids and somatostatin on prolactin and growth hormone release in man. 42 82

We examined splanchnic metabolism of alanine in 15 normal males under three sets of conditions: infusion of saline (control studies); infusion of somatostatin (SRIF) (bihormonal deficiency of insulin and glucagon); and infusion of somatostatin plus insulin (selective glucagon deficiency). Net splanchnic alanine uptake (NSAU) remained stable over 2 h during infusion of saline. Infusion of SRIF was associated with a fall in estimated hepatic plasma flow (EHPF) whether or not insulin was infused concomitantly. With SRIF only, arterio-hepatic venous alanine differences increased such that NSAU remained stable over 2 h, despite the fall in EHPF. In contrast, with selective glucagon deficiency, NSAU fell significantly after 2 h, an effect consequent on a fall in EHPF and a delayed fall in arterio-hepatic venous (A-HV) alanine differences. Our studies are compatible with a role for basal glucagon in maintenance of splanchnic extraction of alanine in normal man. However, the SRIF-initiated fall in EHPF may exert an influence on A-HV alanine differences independent of changes in pancreatic hormone secretion.
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PMID:Splanchnic metabolism of alanine in intact man. Effects of somatostatin and somatostatin plus insulin. 43 78

The aim of the present experiments was to determine the effects of basal glucagon on glucose production after induction of prolonged insulin lack in normal conscious dogs fasted overnight. A selective deficiency of insulin or a combined deficiency of both pancreatic hormones was created by infusing somatostatin alone or in combination with an intraportal replacement infusion of glucagon. Glucose production (GP) was measured by a primed constant infusion of [3H-3]glucose, and gluconeogenesis (GNG) was assessed by determining the conversion rate of circulating [14C]alanine and [14C]lactate into [14C]glucose. When insulin deficiency was induced in the presence of basal glucagon the latter hormone caused GP to double and then to decline so that after 4 h it had returned to the conrol rate. The conversion of alanine and lactate into glucose, on the other hand, increased throughout the period of insulin lack. Withdrawal of glucagon after GP had normalized resulted in a 40% fall in GP, a 37% decrease in GNG, and a marked decrease in the plasma glucose concentration. Induction of insulin deficiency in the absence of basal glucagon resulted in an initial (30%) drop in GP followed by a restoration of normal GP after 2--3 h and moderately enhanced glucose formation from alanine and lactate. It can be concluded that (a) the effect of relative hyperglucagonemia on GP is short-lived; (b) the waning of the effect of glucagon is attributable solely to a diminution of glycogenolysis because GNG remains stimulated; (c) basal glucagon markedly enhances the GNG stimulation apparent after induction of insulin deficiency; and (d) basal glucagon worsens the hyperglycemia pursuant on the induction of insulin deficiency both by triggering an initial overproduction of glucose and by maintaining the basal production rate thereafter.
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PMID:Effect of glucagon on glucose production during insulin deficiency in the dog. 69 Jan 90

A newly developed in vivo method, using the ob-ob strain of obese-hyperglycaemic mice with permanently very high serum insulin values, makes it possible to detect more prolonged serum insulin lowering properties than in normal animals. Two newly synthesized analogues of somatostatin, D-alanine-somatostatin and des-alanine-des glycine-des-amino-somatostatin produced a more prolonged and greater decrease in the serum insulin values of ob-ob mice than did somatostatin. Our new in vivo method makes it possible to investigate the duration of insulin suppression of new derivatives.
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PMID:Prolonged serum insulin decreasing effects of two synthetic somatostatin analogues studied in vivo by a new animal method. Preliminary communication. 71 46


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