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)

Vasoactive intestinal peptide (VIP) stimulated cyclic AMP production in rat peritoneal macrophages. The stimulatory effect of VIP was dependent on time, temperature and cell concentration, and was potentiated by the phosphodiesterase inhibitor 3-isobutyl-1-methylxanthine (IBMX). At 15 degrees C, the response occurred in the 0.1-1000 nM range of VIP concentrations. Half maximal stimulation of cellular cyclic AMP (ED50) was obtained at 1.2 +/- 0.5 nM VIP, and maximal stimulation (about 3-fold basal level) was obtained between 100-1000 nM. The cyclic AMP system of rat peritoneal macrophages showed a high specificity for VIP. The order of potency observed in inducing cyclic AMP production was VIP greater than rGRF greater than hGRF greater than PHI greater than secretin. Glucagon, insulin, pancreastatin and octapeptide of cholecystokinin did not modify cyclic AMP levels at concentrations as high as 1 microM. The beta-adrenergic agonist isoproterenol increased the cyclic AMP production and show additive effect with VIP. Somatostatin inhibits the accumulation of cyclic AMP in the presence of both vasoactive intestinal peptide and isoproterenol. The finding of a VIP-stimulated cyclic AMP system in rat peritoneal macrophages, together with the previous characterization of high-affinity receptors for VIP in the same cell preparation, strongly suggest that VIP may be involved in the regulation of macrophage function.
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PMID:Stimulatory effect of vasoactive intestinal peptide (VIP) on cyclic AMP production in rat peritoneal macrophages. 137 99

The endocrine cells of rainbow trout pyloric ceca and intestine have been investigated immunocytochemically using the avidin-biotin method. Twenty-six antisera were tested and 13 endocrine cell types immunoreacted with antisera to serotonin, somatostatin-25, bombesin, C-flanking bombesin, substance P, salmon PP, NPY, PYY, PP, glucagon, GLP1, Met-enkephalin, and CCK/G. Glucagon and GLP1 immunoreactivities appear in the same cells. Nerves positive to serotonin, substance P, PHI, and VIP were also found. The presence of cells positive to somatostatin-25, C-flanking bombesin, and salmon PP are described for the first time in fish intestine.
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PMID:Endocrine cells and nerves in the pyloric ceca and the intestine of Oncorhynchus mykiss (Teleostei): an immunocytochemical study. 138 78

Functional vasoactive intestinal peptide (VIP) receptors have been characterized in rat peritoneal macrophages. The binding depended on time, temperature and pH, and was reversible, saturable and specific. Scatchard analysis of binding data suggested the presence of two classes of binding sites: a class with high affinity (kd = 1.1 +/- 0.1 nM) and low capacity (11.1 +/- 1.5 fmol/10(6) cells), and a class with low affinity (kd = 71.6 +/- 10.2 nM) and high capacity (419.0 +/- 80.0 fmol/10(6) cells). Structural requirements of these receptors were studied with peptides structurally or not structurally related to VIP. Several peptides inhibited 125I-VIP binding to rat peritoneal macrophages with the following order of potency: VIP greater than rGRF greater than hGRF greater than PHI greater than secretin. Glucagon, insulin, somatostatin, pancreastatin and octapeptide of cholecystokinin (CCK 26-33) were ineffective. VIP induced an increase of cyclic AMP production. Half-maximal stimulation (ED50) was observed at 1.2 +/- 0.5 nM VIP, and maximal stimulation (3-fold above basal levels) was obtained between 0.1-1 microM. Properties of these binding sites strongly support the concept that VIP could behave as regulatory peptide on the macrophage function.
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PMID:Characterization of functional receptors for vasoactive intestinal peptide (VIP) in rat peritoneal macrophages. 165 77

In recent years evidence has accumulated indicating the presence of functional receptors for most neurotransmitters on astrocytes. In particular, receptors coupled to adenylate cyclase have been demonstrated, in primary astrocyte cultures, for vasoactive intestinal peptide (VIP), noradrenaline (NA) and adenosine. Here we provide, in primary cultures of cerebral cortical astrocytes prepared from neonatal mice, a detailed characterization of a cAMP-dependent process elicited by VIP, NA and adenosine, i.e. the hydrolysis of glycogen. The EC50s for the glycogenolytic effect of VIP, NA and adenosine are 3, 20 and 800 nM, respectively. The initial rate of glycogen hydrolysis is, in nmol/mg prot/min, 9.1 for VIP and 7.5 for NA. The effect of NA is predominantly mediated by beta-adrenoceptors, although an alpha 1-adrenergic component, acting most likely through protein kinase C activation, is also present. The action of VIP is mimicked by peptides sharing sequence homologies such as PHI and secretin. Glutamate, GABA, carbachol and the peptides NPY and somatostatin do not influence glycogen levels. The glycogen content of the cultures can be markedly increased by anabolic factors present in fetal calf serum, by high (e.g. 25 mM) glucose in the medium and by 48-h pretreatment of the cultures with dibutyryl cAMP. These results indicate that the glycogen content of astrocytes is under the dynamic control of various factors, including certain neurotransmitters. They also further stress the notion of a functional interaction between neurons and glial cells aimed at maintaining local energy metabolism homeostasis.
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PMID:Characterization of the glycogenolysis elicited by vasoactive intestinal peptide, noradrenaline and adenosine in primary cultures of mouse cerebral cortical astrocytes. 166 73

At present our knowledge of enteric peptide-containing neurons in man is limited. In this study we have used human appendices removed at surgery to examine the peptidergic innervation by immunocytochemistry, immunochemistry, and pharmacological in vitro experiments. Immunocytochemistry revealed a variety of peptide-containing nerve fiber populations in the human appendix. VIP/PHI-, VIP/PHI/NPY-, SP/NKA-, galanin-, and enkephalin-containing nerve fibers were numerous; CGRP- and GRP-containing nerve fibers were moderate in number, while only scattered NPY-, enkephalin/BAM-, and somatostatin-containing nerve fibers could be found. No CCK-, dynorphin A-, or dynorphin B-immunoreactive nerve fibers could be detected. The coexistence of VIP/PHI, SP/NKA, and enkaphalin/BAM can be anticipated from the known sequence of their respective precursors. However, the coexistence of VIP/PHI and NPY was unexpected but corroborates previous observations in other species. Interestingly, SP and CGRP did not seem to coexist in nerve fibers of the human appendix. Immunochemistry (RIA and HPLC) confirmed the presence of VIP, NPY, SP, galanin, CGRP, GRP, enkephalin, and somatostatin. Motor activity studies suggest that acetylcholine plays a major role in the electrically evoked contractions, since atropine suppressed these contractions. Galanin (10(-8)-10(-6) M) and GRP (10(-9)-10(-7) M) caused concentration-dependent contractions that were unaffected by tetrodotoxin and thus probably reflect a direct action on smooth muscle receptors. GRP (10(-9) M) enhanced the electrically induced cholinergic contraction (to 193 +/- 24%), while met-enkephalin (10(-6) M) reduced it (to 54 +/- 6%). Both peptides failed to affect the contractile response to exogenous acetylcholine and probably act to modulate the release of acetylcholine. NPY, VIP, CGRP, SP, and somatostatin failed to induce contraction or to affect the electrically evoked contractions.
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PMID:Neuropeptides in the human appendix. Distribution and motor effects. 247 67

When cytoplasmic extracts of the myenteric plexus of guinea pig ileum are submitted to centrifugal density gradient separation in a zonal rotor, conditions which separate storage particles containing substance P, somatostatin and VIP from each other, PHI copurifies with VIP. The two immunoreactivities cannot be separated by particle exclusion chromatography, which depends on size rather than density. It is concluded that the posttranslational cleavage of the propeptide or precursor to PHI and VIP occurs after packaging into these storage particles.
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PMID:A peptide with N-terminal histidine and C-terminal isoleucine amide (PHI) and vasoactive intestinal peptide (VIP) are copackaged in myenteric neurones of the guinea pig ileum. 278 Apr 16

To determine the effect of vasoactive intestinal peptide (VIP) on the secretion of somatostatin by neurons, dispersed fetal cerebral cortical and diencephalic cells grown in culture were exposed on day 10 or 11 of culture to various concentrations of VIP, and for comparison to the structurally related peptides PHI (Peptide Histidine Isoleucine-27), growth hormone (GRH1-44-NH2) and secretin and to cholecystokinin. VIP elicited a dose-dependent release of somatostatin from both cortical and diencephalic cells, the lowest effective concentration being 6 X 10(-9) M. PHI also brought about release of somatostatin, but was between 0.06 and 0.1 times as potent as VIP. Placed together in a concentration of 10(-7) M, the two peptides did not have an additive effect. In this system GRH1-44-NH2, secretin and CCK octapeptide were without effect.
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PMID:Vasoactive intestinal peptide and PHI stimulate somatostatin release from rat cerebral cortical and diencephalic cells in dispersed cell culture. 286 Sep 51

Bombesin-like immunoreactivity (BLI) has been demonstrated in neurons of the gastrointestinal tract and gastric BLI secretion can be demonstrated in response to the classical neurotransmitter acetylcholine. Since structurally related peptides VIP, PHI and GRF have to be considered as peptidergic neurotransmitters it was of interest to determine their effect on gastric BLI secretion. Additionally, somatostatin (SLI) and gastrin secretion was examined. The isolated stomach of overnight fasted rats was perfused with Krebs-Ringer buffer via the celiac artery and the effluent was collected via the portal vein. The gastric lumen was perfused with isotonic saline at pH7 or pH2. All four peptides were tested at a dose of 10(-11) M and 10(-8) M at both pH levels and in addition the effect of VIP and PHI was examined at 10(-14) M and 10(-12) M during luminal pH2. At luminal pH7 VIP and PHI stimulated SLI release at 10(-8) M but had no effect on BLI or gastrin secretion. rGRF and hpGRF were both ineffective on SLI and gastrin release while rGRF inhibited and hpGRF stimulated BLI secretion. This effect was not dose related. At luminal pH2 all four peptides stimulated BLI secretion. Stimulation by PHI was already observed at a dose of 10(-14) M while VIP elicited a stimulatory effect at 10(-12) M. PHI at the two lowest concentrations of 10(-14) and 10(-12) M elicited a stimulation of SLI and gastrin release while the same doses of VIP and the higher doses of all four peptides had no effect on SLI and gastrin secretion at an acidic intraluminal pH.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Effect of vasoactive intestinal peptide, peptide histidine isoleucine and growth hormone-releasing factor-40 on bombesin-like immunoreactivity, somatostatin and gastrin release from the perfused rat stomach. 287 59

We have earlier demonstrated that human growth hormone stimulates DNA synthesis and proteoglycan production in cultured chondrocytes. The present study is concerned with the effects of somatostatin and other neuropeptides on cell proliferation by cultured rat rib growth plate chondrocytes. Chondrocytes were isolated from the growth plates by collagenase digestion and cultured as monolayers in multiwell plates. The cells were allowed to attach overnight and subsequently incubated for 24 h under serum-free conditions to establish growth arrest. Somatostatin and other peptides were then added and the cultures were incubated for 18 h. Finally, the cultures were labelled for 6 h with tritiated thymidine in the presence of peptide. For screening purposes, the effect on DNA-synthesis was assayed as incorporation of [3H]-thymidine into acid-insoluble material. For a more exact estimate, parallel cultures were prepared for autoradiography and the fraction of labelled nuclei was determined by counting. Among the peptides we tested (somatostatin, GRF, TRH, SP, mENK, PHI, VIP, hCT) only somatostatin had any discernible effect on DNA synthesis, with an apparently optimal effect at 10 fM. This concentration is well within the range found in various tissues in vivo and suggests a physiological role for somatostatin in chondrocyte growth regulation. Further experiments are required, however, to clarify by which mechanism somatostatin influences the cells and whether the peptide interacts with other growth factors such as the IGFs.
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PMID:Stimulative effect of somatostatin on cell proliferation in cultured chondrocytes. 288 5

The new data reported here, and available in the literature, are interpreted to indicate that acute release of PRL in stress is probably mediated by secretion of VIP and PHI arising from a subpopulation of paraventricular cells in the tuberoinfundibular system, and that this secretion is under serotonergic control, presumably by way of the raphe nuclear projection to the hypothalamus. The acute PRL response to suckling response is only partially under VIP/PHI control, and may be regulated by an as yet unidentified neural lobe hormone. In addition to the hypothalamic component of PRL regulation, there is a well-defined population of VIP cells within the pituitary, representing the only known example of VIP expression outside of nerve cells. This population of VIP cells is exquisitely responsive to thyroid status, and in common with the thyrotrope cell, is activated by hypothyroidism. Since VIP secretion is enhanced in the hypothyroid pituitary, and VIP release is stimulated by TRH, it is reasonable to postulate that paracrine VIP secretion may play a role in the reasonable to postulate that paracrine VIP secretion may play a role in the hyperprolactinemia prolactinemia that occurs in the hypothyroid human, although this is clearly not the case for the rat in whom hyperprolactinemia was not demonstrable. The role of VIP/PHI in human pituitary disease is unknown. We have been unable to identify any tumors that contain immunoreactive material using tissues prepared by standard methods. It may be that the demonstration of VIP/PHI is more demanding and will require better techniques for staining. The role of tuberoinfundibular VIP hypersecretion remains to be established but the evidence for stress-induced PRL hypersecretion in man encourages us to believe that at least some cases may be due to excessive hypothalamic activity. Additional potential neuroendocrine actions of VIP are in the secretomotor control of the ovary and thyroid, and in the regulation of somatostatin secretion and synthesis. In dispersed cell cultures (but not in whole hypothalamic slices from adult animals), VIP stimulates somatostatin secretion and independently stimulates the formation of somatostatin mRNA, an effect that can be duplicated in mixed cultures by treatment with forskolin, a postreceptor cAMP stimulator. In work carried out by Montminy and colleagues, the cAMP action has shown to be mediated by formation of a soluble protein that appears to activate the somatostatin gene promotor through interaction with a specific gene sequence.
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PMID:Neuroendocrine significance of vasoactive intestinal polypeptide. 289 11


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