Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P01350 (gastrin)
 9,683 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

A specific receptor for gastrin I has been demonstrated in the rat stomach fundus. Specific binding of 125I-labelled gastrin I was localised to particles sedimenting between 250--20 000 X g. Saturation of binding sites occurred with a gastrin concentration of 10(-11) M in an assay system containing 0.6--1.7 mg/ml of homogenate protein. Gastrin binding was shown to be reversible, temperature- and pH-dependent, and susceptible to tryptic digestion. Electron microscopic and enzymatic studies showed the binding fraction to contain predominantly mitochondria. Preincubation of the homogenate with 10(-8) M cholecystokinin or secretin inhibited gastrin binding to a greater extent than an equimolar concentration of pentagastrin. Cimetidine, a histamine receptor antagonist, did not affect binding of gastrin to the receptor.
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PMID:A specific gastrin receptor site in the rat stomach. 2 75

Guanylate cyclase in the guinea pig fundic mucosa occurred in two enzymatic forms: a "soluble" form and a particulate form. The mean basal activity of the soluble fraction measured in the presence of 300 micrometer guanosine-5'-triphosphate and 5 mM MnCl2 was 72.6 +/- 5.3 pmoles of cyclic GMP per mg of protein per min. Guanylate cyclase activity was dependent on Mn2+; it was increased by sodium azide (NaN3), CaCl2, cysteine, secretin, and cholecystokinin, but it was not influenced by gastrin, histamine, cholinergic esters, prostaglandins E1 and A1. NaN3 (1 mM) decreased the apparent Km for MnCl2 and potentiated the effects of MgCl2. The activity of the particulate fraction represented about 14% of that of the supernatant fraction. The guanylate cyclase activity of that fraction was not modified by NaN3, gastrin, cholinergic agents, secretin, or cholecystokinin. Cysteine inhibited its activity. These data do not support the hypothesis that cyclic GMP acts as a second messenger for the action of cholinergic agents and gastrin in the guinea pig gastric mucosa.
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PMID:Effect of Ca2+, Mg2+, NaN3, cholinergic agents, and gastrointestinal hormones on the guanylate cyclase from guinea pig gastric mucosa. 2 35

Immunoreactive gastrin was present in vagal nerves from cats, dogs, and human beings. The abdominal portion of the vagus contained gastrin in amounts ranging from 16 to 273 pmol/g of nerve tissue (wet weight). The thoracic and cervical portion of the vagi contained only minute amounts of gastrin. Gel chromatography of extracts of human, canine, and feline abdominal vagi monitored by region-specific antisera against heptadecapeptide gastrin and triacontatriapeptide cholecystokinin revealed that the vagal gastrin immunoreactivity predominantly consisted of heptadecapeptide gastrin. In addition, the vagi contained small amounts of the NH2-terminal tridecapeptide gastrin fragment as well as of the putative biosynthetic gastrin precursors, components I and II. No cholecystokinin-like molecules were demonstrable. Immunocytochemical studies demonstrated gastrin-containing nerves in the intestinal wall. The nerves were found to be most numerous in the large and distal small intestine. These findings suggest that heptadecapeptide gastrin may represent a new vagal neurotransmitter.
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PMID:Heptadecapeptide gastrin in the vagal nerve. 2 37

Biochemical assays on microdissected samples, denervation studies, subcellular fractionation, and light and electron microscopic autoradiography of high affinity uptake have been performed to study the cellular localization of transmitter candidates in the rat hippocampal formation. High affinity uptake of glutamate and aspartate is localized in the terminals of several excitatory systems, such as the entorhino-dentate fibres (perforant path), mossy fibres (from granular cells) and pyramidal cell axons. Thus, in stratum radiatum and oriens of CA1, 85% of glutamate and asparate uptake and 40% of glutamate and aspartate content are lost after lesions of ipsilateral plus commissural fibres from CA3/CA4. Hippocampal efferents also take up aspartate and glutamate, since these activities are heavily reduced in the lateral septum and mamillary bodies after transection of fimbria and the dorsal fornix. The synthesis (by glutamic acid decarboxylase), content and high affinity uptake of gamma-aminobutyrate (GABA) are not reduced after lesions of these or other projection fibre systems. A localization in intrinsic neurons is confirmed by a selective loss of glutamic acid decarboxylase after local injections of kainic acid. Peak concentrations of the enzyme occur near the pyramidal and granular cell bodies, corresponding to the site of the inhibitory basket cell terminals, and in the outer parts of the molecular layers. Some 85% of glutamic acid decarboxylase is situated in 'nerve ending particles'. Acetylcholine synthesis (by choline acetyltransferase) disappears after lesions of septo-hippocampal fibres. Since 80% of the hippocampal choline acetyltransferase is in 'nerve ending particles', the characteristic topographical distribution of this enzyme should reflect the distribution of cholinergic septo-hippocampal afferents. Serotonin, noradrenaline, dopamine and histamine are located/synthesized in afferent fibre systems. Some monoamine-containing afferents to the hippocampal formation pass via the septal area, others via the amygdala. The hippocampal formation also contains nerve elements reacting with antibodies against neuroactive peptides, such as enkephalin, substance P, somatostatin and gastrin/cholecystokinin.
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PMID:Localization of putative transmitters in the hippocampal formation: with a note on the connections to septum and hypothalamus. 3 19

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

Both immunoreactive intact cholecystokinin (CCK33) and its COOH-terminal octapeptide (CCK8) are detected in brain and gut extracts of monkey, dog, and pig using an antiserum with equivalent sensitivities for detecting CCK8 in the free form or when incorporated in the intact molecule. The failure to detect intact cholecystokinin in extracts from monkey or dog by using an antiserum developed by immunization with porcine CCK33 is due to marked species differences in the NH2-terminal portion of the molecule. Immunohistochemical staining reveals the presence of CCK peptides in rabbit cerebral cortical tissue neurons. Subcellular fractionation of rat cerebral cortical tissue demonstrates that CCK immunoreactivity is concentrated in the pellet identified by electron microscopy to contain a high proportion of synaptic vesicles. A converting enzyme that differs from trypsin has been partially purified from canine and porcine cerebral cortical extracts. It converts porcine CCK to smaller immunoreactive forms, but fails to convert big gastrin to heptadecapeptide gastrin. This enzyme differs from trypsin not only in substrate specificity but also in several physicochemical properties. Cerebral cortical extracts from hyperphagic ob/ob mice have strikingly lower contents of CCK than those from their lean littermates and other normal mice. These studies taken together are consistent with a role for CCK as a neurotransmitter involved in the overall regulation of appetite.
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PMID:Gastrointestinal peptides in the brain. 11 Jun 22

Reliable and specific radioimmunoassays have been developed for the gut hormones secretin, gastrin, cholecystokinin, pancreatic glucagon, VIP, GIP, motilin, and enteroglucagon. Using these assays, the relative pattern of distribution of the gut hormones has been determined using the same bowel extracts for all measurements. VIP occurred in high concentration in all regions of the bowel, whereas secretin, GIP, motilin, and CCK were predominantly localised in the proximal small intestine. Pancreatic glucagon was almost exclusively confined to the pancreas. Like VIP, enteroglucagon also exhibited a wide pattern of distribution but was maximal in the ileum. The acid ethanol extraction method that was used was found to be unsuitable for gastrin. On gel chromatography of the extracts, motilin and VIP eluted as single molecular species in identical position to the pure porcine peptides. CCK, pancreatic glucagon, enteroglucagon and GIP were all multiform.
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PMID:Distribution of the gut hormones in the primate intestinal tract. 11 57

Mechanical length-tension properties and response to neurohumoral agents were compared for proximal and distal colonic muscle. Resting tension during stretch, acetylcholine-stimulated tension, and the total tension were determined. Proximal circular muscle developed a maximum total tension of 0.96 +/- 0.18 kg/cm2 (mean +/- SE) compared to 0.86 +/- 0.06 kg/cm2 for the distal colon (P greater than 0.05). Resting tension was 0.33 +/- 0.03 kg/cm2 for the proximal colon and 0.05 +/- 0.01 kg/cm2 for the distal colon at the length of optimal acetylcholine-stimulated tension (Lo) (P less than 0.01). Longitudinal muscle showed a similar difference for the proximal and distal colon. The high resting tension in the proximal colonic muscle was reduced by nitroprusside or calcium-free Krebs with EGTA. Dose-response curves to acetylcholine, histamine, phenylephrine, and isoproterenol were similar for the muscle of either part of the colon. Gastrin or cholecystokinin had no effect on the muscle. In summary, the circular or longitudinal muscles of the proximal and distal colon have different length-tension properties but only minimal differences in response to neurohumoral agents.
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PMID:Comparison of proximal and distal colonic muscle of the rabbit. 11 18

The effects of a number of peptides which are found in the gastrointestinal tract have been ascertained on the direct current recorded dorsal and ventral root responses of the isolated hemisected toad spinal cord. Motilin, substance P, bombesin, neurotensin, and thyrotropin releasing hormone had potent depolarizing actions on dorsal root terminals and motoneurons. These substances evoked discernable effects at concentrations as low as 10--7 M, or even lower with motilin. The effects of motilin, neurotensin, and thyrotropin-releasing hormone were greatly reduced or abolished by perfusion of the preparation with tetrodotoxin. Adrenocorticotrophic hormone, secretin, and pancreozymin (cholecystokinin) also depolarized dorsal root terminals and motoneurons. The effects of secretin and cholecystokinin were not abolished by tetrodotoxin. Leu- and Met-enkephalin had weak hyperpolarizing actions on the dorsal and ventral root potentials of repetitively stimulated preparations. Gastrin, gastric inhibitory peptide, glucagon, and somatostatin had no apparent effects on the responses of the preparation. Angiotensin and vasopressin both had rather weak depolarizing effects on the dorsal and ventral roots.
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PMID:Actions of various gastrointestinal peptides on the isolated amphibian spinal cord. 11 60

Caerulein is a decapeptide which combines the effects of gastrin and cholecystokinin-pancreozymin. It was injected intravenously in doses of 10 to 40 nanoponds caerulein per kilopond bodyweight in 37 patients and roentgen kymography of the stomach carried out before and after the injection. In 89% of the 36 cases which could be evaluated, it increased antral peristalsis. Amplitude and frequency were increased and the periodicity decreased correspondingly. The effect was more marked than that of pentogastrin, presumably because caerulein dose not affect duodenal acidity. The changes in motility therefore correspond with those produced by serotonin and cholecystokinin-pancreoxymin. Control examinations carried out under identical conditions, but without caerulein, showed no change in antral peristalsis.
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PMID:[Roentgen kymographic investigations of gastric peristalsis after intravenous injection of caerulein]. 12 10


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