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)

Choline accumulation, choline acetyltransferase (ChAT) and glutamic acid decarboxylase (GAD) activities were measured simultaneously in various cerebrovascular beds and brain areas from Fischer 344 rats aged 4.5 and 22 months. A slight (25%) but not significant decrease in choline accumulation was observed concomitantly with a significant increase (187%, p less than 0.05) in ChAT activity in the major cerebral arteries of the 22-month-old rats. In small cortical pial vessels and selected brain regions, cholinergic and GABAergic biochemical markers remain unaltered in aged rats. The vasomotor reactivity of the basilar artery was investigated in rats of 4.5, 12, 22 and 30 months of age. In the 22-month-old rats, maximal responses to 5-hydroxytryptamine (-25%, no significant) and prostaglandin F2 alpha (-30%, p less than 0.05 by ANOVA) were less intense as compared to other age-groups despite preserved contractile responses to dopamine, uridine triphosphate or a depolarizing concentration of K+. Relaxations induced by histamine, acetylcholine, noradrenaline, adenosine and somatostatin were strictly comparable among the different age-groups. The sensitivity of the basilar artery to all vasoactive agents failed to demonstrate any correlation with age. Our study suggests that cerebrovascular cholinergic and GABAergic markers undergo minor and selective changes with increasing age. Further, basilar artery vasomotor functions appeared relatively spared by the aging process despite age-related selective decreases in contractile responses to 5-hydroxytryptamine and prostaglandin F2 alpha.
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PMID:Selective age-related changes in neuronal markers and smooth muscle reactivity in cerebrovascular beds of Fischer 344 rats. 198 Jul 21

A clonal cell line (44-2C) which synthesizes and secretes somatostatin, neurotensin, calcitonin (CT), and CT gene-related peptide and transiently expresses c-fos was used to characterize the mechanism of action of basic fibroblast growth factor (bFGF). bFGF had two modes of action: 1) short term incubation of 44-2C cells with bFGF increased the cellular content of neurotensin, somatostatin, and CT; and 2) bFGF enhanced the response of the cells to rat hypothalamic GRF-mediated cAMP efflux. The long term action of bFGF was manifested by the permissive effect of the molecule. bFGF had a sustained effect on RNA synthesis, and pretreatment with bFGF for 24 h altered the time course of response of the cells to rat GRF. In this cell line the cellular action of bFGF was not mediated via protein kinase-C action. bFGF was not mitogenic in 44-2C cells. bFGF stimulated uridine incorporation without affecting thymidine incorporation. Results obtained with actinomycin-D and alpha-amanitin suggest that the above effects of bFGF can be correlated with increased RNA stability produced by bFGF.
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PMID:Fibroblast growth factor stabilizes ribonucleic acid and regulates differentiated functions in a multipeptide-secreting neuroendocrine cell line. 244 40

Binding of [125I]monoiodoinsulin to human astrocytoma cells (U-373 MG) was time dependent, reaching equilibrium after 1 h at 22 degrees C with equilibrium binding corresponding to 2.2 fmol/mg protein: this represents approximately 2,000 occupied binding sites per cell. The t1/2 of 125I-insulin dissociation at 22 degrees C was 10 min; the dissociation rate constant of 1.1 X 10(-2) s-1 was unaffected by a high concentration of unlabeled insulin (16.7 microM). Porcine insulin competed for specific 125I-insulin binding in a dose-dependent manner and Scatchard analysis suggested multiple affinity binding sites (higher affinity Ka = 4.4 X 10(8) M-1 and lower affinity Ka = 7.4 X 10(6) M-1). Glucagon and somatostatin did not compete for specific insulin binding. Incubation of cells with insulin (0.5 microM) for 2 h at 37 degrees C increased [2-14C]uridine incorporation into nucleic acid by 62 +/- 2% (n = 3) above basal. Cyclic AMP, in the absence of insulin, also stimulated nucleoside incorporation into nucleic acid [65 +/- 1% (n = 3)] above basal. Preincubation with cyclic AMP followed by insulin had an additive effect on nucleoside incorporation [160 +/- 4% (n = 3) above basal]. Dipyridamole (50 microM), a nucleoside transport inhibitor, blocked both basal and stimulated uridine incorporation. These studies confirm that human astrocytoma cells possess specific insulin receptors with a demonstrable effect of ligand binding on uridine incorporation into nucleic acid.
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PMID:Insulin binding to human astrocytoma cells and its effect on uridine incorporation into nucleic acid. 256 7

Binding of 125I-insulin to primary cultures of differentiated mouse astrocytes was time-dependent, reaching equilibrium after 2 h at 22 degrees C, with equilibrium binding corresponding to 20.79 fmol/mg of protein, representing approximately 5,000 occupied binding sites/cell. The half-life of 125I-insulin dissociation at 22 degrees C was 2 min, with an initial dissociation rate constant of 4.12 X 10(-2) s-1. Dissociation of bound 125I-insulin was not accelerated significantly in the presence of unlabeled insulin (16.7 microM). Porcine and desoctapeptide insulins competed for specific 125I-insulin binding in a dose-dependent manner, whereas growth hormone, glucagon, and somatostatin did not. For porcine insulin, Scatchard analysis suggested multiple-affinity binding sites (high-affinity Ka = 4.92 X 10(8) M-1; low-affinity Ka = 0.95 X 10(7) M-1). After incubation with insulin (0.5 microM) for 2 h at 37 degrees C, increases above basal values of 254 +/- 23 and 189 +/- 34% for [3H]uridine uptake and incorporation, respectively, were observed. After incubation with insulin (0.5 microM) for 24 h at 37 degrees C, there were increases of 145 +/- 6% for [3H]thymidine uptake and 166 +/- 11% for thymidine incorporation. Basal and stimulated uridine and thymidine uptake and incorporation were inhibited by 50 microM dipyridamole. These studies confirm that mouse astrocytes in vitro possess specific insulin receptors and demonstrate an effect of insulin on pyrimidine nucleoside uptake and incorporation.
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PMID:Insulin binding and effects on pyrimidine nucleoside uptake and incorporation in cultured mouse astrocytes. 330 89

By means of radioimmunoassay procedures, cholecystokinin-(CCK) and somatostatin-(SRIF) like immunoreactivity have been studied in the dorsal hippocampal formation and in the frontoparietal cortex of the male rat in insulin-induced hypoglycaemia, leading to an isoelectric EEG pattern. It has been demonstrated that severe hypoglycaemia of 40-min-duration produces a disappearance of SRIF but not of CCK-like immunoreactivity in both cortical regions. It was found that an i.v. injection of uridine but not of saline could significantly counteract the disappearance of SRIF-like immunoreactivity induced by severe hypoglycaemia in both cortical areas. Uridine did not by itself change plasma glucose levels. It is suggested that uridine may prevent release and/or increase synthesis of cortical SRIF peptides in severe hypoglycaemia, possibly due to an action on the metabolism (e.g. by enhancing the resynthesis of phosphatidyl inositol) within the tissue of the cerebral cortex and/or on putative pyrimidine binding sites in the brain controlling SRIF synthesis and/or release. It is possible that uridine in this way may improve recovery of neuronal function within SRIF-immunoreactive neurons of the cerebral cortex after severe hypoglycaemia (which also may be true in other states of reduced metabolic support). These findings suggest a possibility to use uridine in the treatment of Alzheimer's disease and Status epilepticus.
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PMID:Intravenous uridine treatment antagonizes hypoglycaemia-induced reduction in brain somatostatin-like immunoreactivity. 352 Dec 3

Neuropeptide Y (NPY), substance P (SP), vasoactive intestinal polypeptide (VIP), calcitonin gene-related peptide (CGRP), lysyl-bradykinin, somatostatin, Met- and Leu-enkephalin were tested for their smooth muscle activity in isolated human mesenteric arteries and veins. Only NPY regularly contracted both arteries and veins. Alpha-adrenergic and 5-HT2 antagonists did not affect the response. Somatostatin contracted the veins, but not the arteries, in a variable but concentration-dependent way. The other neuropeptides were without contractile effect. CGRP, bradykinin, and SP regularly dilated, in a concentration-dependent way, both arteries and veins precontracted with prostaglandin F2 alpha or uridine triphosphate. CGRP and bradykinin were the most potent dilators. VIP and somatostatin usually caused a moderate dilatation in the arteries, whereas in the veins, somatostatin was without dilatory effect and the VIP-induced dilatation was irregular. In both types of vessels Met-enkephalin seldom gave any significant dilatation, and no response occurred in the presence of Leu-enkephalin or NPY. The SP-antagonist (D-Arg, D-Trp, Leu)-SP (spantide) caused a dextal shift of the concentration-response curves for SP, in the case of the arteries also including a reduced maximum effect.
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PMID:Contractile and dilatory action of neuropeptides on isolated human mesenteric blood vessels. 358 45

We studied the effects of somatostatin on synthesis of pancreatic DNA, RNA and protein and on pancreatic weight and contents of DNA, protein, amylase and chymotrypsinogen in rats. In short term synthesis studies, rats were injected with 100 micrograms . kg-1 somatostatin or 0.15 M NaCl (control) at times 0, 8 and 16 h. Eight rats from each treatment group were killed 2, 4, 8, 12, 16, 20 and 24 h after beginning treatment. Incorporation rates in vivo of [3H]thymidine into DNA, [3H]uridine into RNA and [14C]phenylalanine into total protein were significantly depressed by somatostatin. In long term studies, four groups of 12 rats were injected every 8 h for 5 days with 0.15 M NaCl or 11, 33 or 100 micrograms . kg-1 somatostatin. Body weight was unaffected but pancreatic contents of DNA, protein and enzymes were significantly decreased by somatostatin. Administration of somatostatin inhibits DNA, RNA and protein synthesis in exocrine pancreas with resulting decreases in DNA and enzyme contents.
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PMID:Effects of chronic administration of somatostatin on rat exocrine pancreas. 618 37

The addition of thyroid hormone to cultures of GH3 or GH4C1 pituitary tumor cells maintained in medium with hypothyroid serum decreased the concentration of specific receptors for TRH. The relationship between thyroid hormone effects on TRH receptors and TRH responses was examined by testing the concentration dependence, time course, and specificity of these changes. The concentrations of T3 giving half-maximal decreases in [3H]TRH binding and inhibition of the PRL response to TRH were 0.20 and 0.24 nM, respectively. TRH stimulated the rate of [3H]uridine uptake by 50% in cultures incubated without added T3 but did not increase [3H]uridine uptake in cells incubated with thyroid hormone. The PRL response to TRH was substantially inhibited 12 h after the addition of T3, and the uridine uptake response was completely blocked in 8 h. Two other stimuli of PRL secretion, sodium butyrate and isobutylmethylxanthine, were effective in the presence or absence of T3. Thyroid hormone did not reduce the specific binding of either [125I-Tyr1]somatostatin or [125I]iodoepidermal growth factor. Somatostatin decreased the secretion of GH and PRL by pituitary tumor cells grown with or without T3. The data show that the effects of thyroid hormones on TRH receptors are specific and suggest that regulation of receptor concentrations may be the direct cause of thyroid hormone regulation of pituitary responsiveness to TRH.
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PMID:Mechanism of thyroid hormone inhibition of thyrotropin-releasing hormone action. 625 85

We have investigated the effects of somatostatin (SRIF) and the linear octapeptide BIM-23056 on changes in intracellular calcium ion concentration ([Ca2+]i) and on the formation of inositol-1,4,5-trisphosphate (Ins(1,4,5)P3) in CHO-K1 cells transfected with the human recombinant SRIF sst5 receptor. SRIF elicited concentration-dependent increases in [Ca2+]i, with a pEC50 of 7.02 +/- 0.06, while BIM-23056 (1 x 10(-7) M) behaved not as an agonist but as a potent, surmountable antagonist of these increases in [Ca2+]i. The SRIF concentration-effect curve for increases in [Ca2+]i was shifted rightward producing an estimated pKB for the antagonist of 8.0. BIM-23056 (1 x 10(-7) M) also significantly attenuated Ins(1,4,5)P3 increases due to SRIF, but had no effect on either basal or uridine 5'-triphosphate (UTP) (1 x 10(-4) M) stimulated increases in the levels of [Ca2+]i or Ins(1,4,5)P3.
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PMID:Potent antagonism by BIM-23056 at the human recombinant somatostatin sst5 receptor. 876 63

1. We have functionally characterized the human recombinant somatostatin (SRIF) sst5 receptor in Chinese hamster ovary-K1 (CHOsst5) cells by measuring total [3H]-inositol phosphate ([3H]-InsPx) accumulation, in the presence of 10 mM LiCl, in cells labelled with [3H]-myo-inositol. 2. In CHOsst5 cells, SRIF, SRIF-28 and the cyclic hexapeptide, L-362,855, produced time- and concentration-related increases in [3H]-InsPx accumulation, with similar potency (pEC50 values of 6.5, 6.8 and 7.2, respectively). L-362,855 behaved as a partial agonist, producing approximately 30% of the SRIF maximum response. The other peptide analogues of SRIF, BIM-23027 and BIM-23056, were inactive as agonists. 3. Increasing concentrations of L-362,855 increased [3H]-InsPx accumulation and simultaneously produced rightward shifts of SRIF concentration-effect curves, with an estimated pKp value of 7.6, confirming that it was acting as a partial agonist. 4. BIM-23056, but not BIM-23027, potently antagonized SRIF-induced [3H]-InsPx accumulation, with an estimated pKB value of 7.4. BIM-23056 did not antagonize [3H]-InsPx accumulation induced by uridine 5'-triphosphate (UTP). 5. SRIF- but not UTP-induced [3H]-InsPx accumulation was inhibited by increasing concentrations of pertussis toxin (0.01-100 ng ml-1), indicating the involvement of pertussis toxin-sensitive G-proteins. 6. These findings show that the human recombinant sst5 receptor, when stably expressed in CHO-K1 cells, is able to mediate activation of phosphoinositide metabolism in a pertussis toxin-sensitive manner. In this system L-362,855 behaved as a partial agonist while BIM-23056 was a specific antagonist. These agents should provide useful tools for functionally characterizing endogenous SRIF receptors.
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PMID:Characterization of human recombinant somatostatin sst5 receptors mediating activation of phosphoinositide metabolism. 914 92


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