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)

The effect of somatostatin, an inhibitor of release of a number of gastrointestinal and other hormones, on choleresis was investigated in chronic, bile fistula dogs with taurocholate-stabilized bile flow. Somatostatin inhibited both fasting and meal-stimulated choleresis, and bile flows during somatostatin inhibition of both fasting and fed dogs were similar, suggesting a complete suppression of factors causing feeding choleresis. Although a transient decrease in bile salt output was observed, bile salt output was unaffected during most of the period of bile flow inhibition. Hormone suppression by somatostatin, indicated by measurement of serum insulin, occurred over a similar time course as inhibition of choleresis. These observations provide further evidence for physiological humoral regulation of choleresis.
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PMID:Inhibition of basal and meal-stimulated choleresis by somatostatin. 46 76

Filtration of basal plasma from normal, alloxan-diabetic, and depancreatized dogs on Bio Gel P-10 yielded four glucagon-immunoreactive fractions. One of them appeared in the true glycagon area with the glucagon-125I (3500 mol vt). Of the other three, one appeared in the void volume (greater than 20000 mol wt), another just before the insulin-125I (congruent to 9000 mol wt), and the last one close to the salt peak (less than 2000 mol wt). The increase of total plasma glucagon immunoreactivity observed in depancreatized and alloxan diabetic dogs was mainly due to an increase in the 3500 and 9000 molecular-weight fractions. Arginine infusion in depancreatized dogs caused an increase in the 3500 molecular-weight fraction. Somatostatin or insulin infusion in depancreatized and alloxan-diabetic dogs resulted in disappearance of the 3500 molecular-weight fraction.
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PMID:Heterogeneity of plasma glucagon immunoreactivity in normal, depancreatized, and alloxan-diabetic dogs. 115 74

Effects of liver denervation on bile formation were studied in eight dogs prepared with chronic biliary fistulas. The animals were studied in the basal state, after feeding, and during infusion of glucagon 50 ng/kg/min, secretin 2 U/kg/hr, or somatostatin 200 ng/kg/min. After this first set of experiments the animals underwent a total hepatic denervation that consisted of section of the hepatic ligaments and a careful dissection of the portal vein, hepatic artery, and common duct with stripping of all the surrounding connective tissue and topical application of phenol. The above experiments were then repeated. Denervation did not modify bile flow, or bile salts, cholesterol, or phospholipid concentration or output. Biliary response to glucagon and secretin was similar before and after denervation. Somatostatin had an anticholerectic effect in both intact and denervated animals, but significantly reduced bile salt output only in the intact dogs. Feeding had a choleretic effect pre- and postdenervation, and the infusion of somatostatin following feeding decreased bile flow to the same degree before and after denervation. In the intact animals the output of all three biliary lipids was reduced by somatostatin after feeding but they were unaffected by somatostatin after denervation. Moreover, cholesterol and phospholipid outputs were stable after feeding in intact animals, but significantly decreased after denervation. 14C-erythritol clearance studies indicated no change in the canalicular component of bile flow with denervation, except again during somatostatin suppression of feeding. These data indicate that basal bile flow is normal after denervation but that innervation may play an important role in the modulation of responses to somatostatin and more complex stimuli such as feeding.
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PMID:The effects of liver denervation on the regulation of hepatic biliary secretion. 135 20

Despite the proposal that somatostatin or its stable analogue, octreotide (SMS-201,995), may exert an ameliorating effect on acute pancreatitis, data concerning its beneficial effect in this situation are conflicting. This study examines the effects of octreotide on acute pancreatitis, resulting from the retrograde injection of a bile salt (taurocholate) plus saturating trypsin into the common bile-pancreatic duct of the rat. Octreotide given before the induction of pancreatitis significantly reduced the levels of serum amylase and lipase, ascites amylase concentration, degree of leukocyte infiltration, and focal areas of pancreatic tissue necrosis. In contrast, administration of octreotide as soon as 5 min following induction had no demonstrable ameliorating effects on the pancreatitis. These results indicate that octreotide may have application to prophylaxis of acute pancreatitis in cases where bile salts may play a role in pathogenesis, but may not be beneficial in established acute pancreatitis.
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PMID:A somatostatin analogue is protective against retrograde bile salt-induced pancreatitis in the rat. 171 27

The mammalian DNA repair enzyme beta-polymerase is encoded by a single-copy gene that is expressed in all tissues and cell lines studied to date. A protein fraction with high binding affinity for an ATF/CREB-like binding element, GTGACGTCAC, at -49 to -40 in the core beta-polymerase promoter has been purified to near-homogeneity from a nuclear extract of bovine testes. The major binding activity, as monitored by gel mobility shift assay, is recovered in 20% yield by a procedure involving oligonucleotide affinity chromatography. The purified protein yields DNase I footprinting and gel shift binding patterns indistinguishable from the activity in crude extracts. The final fraction activates transcription in an in vitro transcription reaction. The native molecular weight of the purified binding activity is about 100-120K as measured by gel filtration. SDS-PAGE of the purified fraction revealed that it contains several polypeptides in the molecular weight range of 30-52K, yet two of these peptides (Mr 49K and 52K) are predominant. Specific binding to the palindrome is salt-sensitive and is consistent with the formation of nine ion pairs (from log KA vs log KCl plots) and has a KA at 200 mM KCl of 5.8 X 10(11) M-1. Kinetic studies with synthetic oligonucleotides as binding ligands indicate that the purified protein can bind tighter to or discriminate between the beta-polymerase ATF/CREB element and similar elements derived from somatostatin and chorionic gonadotropin genes.
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PMID:Mammalian beta-polymerase promoter: large-scale purification and properties of ATF/CREB palindrome binding protein from bovine testes. 182 81

The binding of the cyclic somatostatin analogue SMS 201-995, (+)-D-Phe1-Cys2-Phe3-D-Trp4-(+)-Lys5-Thr6- Cys7-Thr(ol)8, to neutral and negatively charged lipids was investigated with a centrifugation assay and with electrophoretic and monolayer methods. Monolayers and bilayers were composed of 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine (POPC) and 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphoglycerol (POPG), either in pure form or in a 75/25 (mol/mol) mixture. The expansion of monolayer films demonstrated the intercalation of the peptide between the lipid molecules with a surface area requirement of 135 A2 per peptide molecule, indicating a parallel alignment of the peptide long axis with the membrane surface. Above a limiting pressure of 32.5 mN/m for POPC and 38.5 mN/m for POPG, peptide penetration was no longer possible. The peptide binding isotherm could be measured for mixed POPC/POPG bilayers up to a peptide concentration of 0.5 mM. Due to electrostatic attraction, binding between the positively charged peptide and the negatively charged membrane surface was enhanced as compared to the binding to a neutral membrane. After correction for electrostatic effects by means of the Gouy-Chapman theory, the binding isotherm as well as the electrophoretic zeta-potential measurement could be described by the same partition equilibrium with a surface partition constant of Kp = 36 +/- 4 M-1 (at 0.1 M NaCl). About 60-70% of SMS 201-995 is probably embedded in the headgroup region with little penetration into the lipid core. The partition constant increases with increasing salt concentration or with decreasing lipid lateral pressure.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Peptide binding to lipid bilayers. Binding isotherms and zeta-potential of a cyclic somatostatin analogue. 227 94

The effects of extrinsic and intrinsic nerves on ion and water transport by the intestine are considered and discussed in terms of their possible physiological function. Adrenergic nerves enter the small intestine via mesenteric nerves. Adrenergic tone is usually absent in tissues in vitro but is present in vivo. The nerves increase absorption in response to homeostatic changes associated with acute depletion of extracellular fluid. Cholinergic tone that reduces fluid absorption or causes secretion has been detected in the small intestine of humans, dogs, and cats and in the colon of humans. Extrinsic cholinergic fibers generally do not affect ion transport in small intestine but probably do so in colon. Whether peptides liberated in the mucosa affect enterocytes directly is not clear. Studies on humans and rabbits suggest that the role of substance P is minor. The physiological roles of vasoactive intestinal polypeptide (VIP) and somatostatin remain to be defined. Intraluminal factors also affect ion and water transport. Mucosal rubbing, distension, and cholera toxin cause fluid secretion; acid solutions in the duodenum cause alkaline secretion; these stimuli and hypertonic glucose liberate serotonin into the lumen, the mesenteric venous blood, or both. It has been proposed that the enterochromaffin cell is an epithelial sensory cell that responds to noxious stimuli within the lumen by liberating serotonin. The serotonin initiates a neural reflex through a nicotinic ganglion to liberate a secretagogue that acts on the enterocyte. The function of VIP in this proposed reflex is unclear. The variety of intraluminal stimuli that influence epithelial function implies that there is more than one type of epithelial sensory cell (or sensory mechanism). Prostaglandins may mediate the alkaline secretion caused by acid in the duodenum. There may be other effective substances. Although it has been known for years that intraluminal stimuli affect the coordination of smooth muscle functions, it is not known whether similar stimuli also influence salt and water transport as a meal traverses the alimentary canal.
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PMID:Intestinal nerves and ion transport: stimuli, reflexes, and responses. 257 77

Previous experiments have demonstrated the cholestatic effects of somatostatin administration in several animal species. These effects were confirmed in the rat. Nine pairs of intact awake rats received intravenous sodium taurocholate (23 mg hr-1) to stabilize bile flow, and half were later given somatostatin at doses of 185 micrograms hr-1. After 1 hr of somatostatin the experimental group showed a significant decrease in bile flow compared to the control group. Cholestasis reversed when somatostatin infusion was stopped. An in situ isolated perfused rat liver technique was used to assess the direct effects of somatostatin on biliary flow. In 10 pairs of rat livers, after achieving stable bile flow, half of those perfused (the "experimentals") received continuous (370 micrograms hr-1) somatostatin infusion, while the controls received saline. The percentage change in bile flow from baseline in the somatostatin group was not significantly different from that in controls for any test period. Bile analysis revealed no significant differences between groups for cholesterol, phospholipid, or bile salt concentrations or outputs. These data suggest that somatostatin inhibits bile secretion by some mechanism other than direct inhibition of bile secretory mechanisms.
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PMID:Is somatostatin a directly acting cholestatic hormone? 286 22

The peptide somatostatin (SRIF) is secreted by delta cells of the endocrine pancreas and inhibits the secretion of insulin from pancreatic beta cells. We have previously shown that [125I-Tyr11]SRIF binds to specific, high affinity receptors on RINm5F insulinoma cells and that these receptors mediate the action of SRIF to inhibit insulin release. In the present study we investigated the processing of receptor-bound [125I-Tyr11]SRIF in this clonal cell line. Surface-bound and internalized peptides were distinguished by the ability of an acid/salt solution (0.2 M acetic acid, 0.5 M NaCl, pH 2.5) to dissociate only exposed ligand-receptor complexes. Surprisingly, greater than 80% of saturably bound [125I-Tyr11]SRIF was removed by this acid wash independent of the time or temperature of the binding incubation. In contrast, the processing of receptor-bound [125I]EGF (epidermal growth factor) in RINm5F cells was markedly temperature-dependent. Although over 90% of saturably bound [125I]EGF was dissociated by acid after a 4 degrees C binding incubation, less than 10% was removed by acid treatment after 37 degrees C binding. The radioactivity released upon dissociation of receptor-bound [125I-Tyr11]SRIF was analyzed by high performance liquid chromatography and shown to consist of a mixture of intact peptide (40%) and [125I]tyrosine (60%). However, neither the rate of [125I-Tyr11]SRIF dissociation nor its degradation were affected by NH4Cl, methylamine, or leupeptin at concentrations which inhibited the lysosomal degradation of [125I] EGF. Of 11 other protease inhibitors tested, only the metalloendoprotease inhibitor, phosphoramidon, substantially reduced the degradation of receptor-bound [125I-Tyr11]SRIF. These data indicate that, unlike [125I] EGF, receptor-bound [125I-Tyr11]SRIF is not rapidly internalized by RINm5F cells and is degraded by a nonlysosomal process which may involve a metalloendoprotease.
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PMID:The processing of receptor-bound [125I-Tyr11]somatostatin by RINm5F insulinoma cells. 286 33

The effect of oral lidamidine hydrochloride and subcutaneous long acting somatostatin analogue, SMS 201-995, on stool output and salt and water transport in the small intestine was investigated in a patient with gross secretory diarrhoea caused by a vasoactive intestinal polypeptide (VIP) secreting tumour in the liver. Transport in the jejunum and ileum were assessed by steady state perfusion techniques. Under basal conditions, the patient was absorbing fluid and electrolytes from the jejunum and ileum, but at rates that were abnormally low. Lidamidine had no effect on either intestinal transport or stool frequency and output. SMS 201-995 increased intestinal absorption in the jejunum and ileum, reduced plasma VIP concentrations, daily stool frequency and weight, and enabled the patient to resume a normal diet without oral or intravenous fluid and electrolyte supplements. After two months of treatment, medical control was becoming increasingly difficult and stool output had risen again to 2 litres per day. Surgical resection, fortunately, was possible and led to resolution of symptoms and normal plasma VIP concentrations.
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PMID:Effect of two new antisecretory drugs on fluid and electrolyte transport in a patient with secretory diarrhoea. 287 Sep 57


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