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)

The peptide gastrin has been shown to have growth stimulatory effects on normal as well as malignant gastrointestinal tissue. In this study, we have examined the possibility of autocrine growth-stimulation of cultured colon tumor cells by a gastrin-like peptide. The gastrin/CCK receptor antagonist dibutyryl cGMP inhibited the proliferation of two human colon carcinoma cell lines HCT 116 (EC50 = 1.3 mM) and CBS (EC50 = 2.5 mM) in a dose-dependent manner. Marked morphological changes were observed in HCT 116 cells after treatment with 1 mM dibutyryl cGMP. In receptor binding assays, dibutyryl cGMP competed with 125I-labeled gastrin for binding to HCT 116 cells (IC50 = 1.8 mM). Another derivative of cyclic GMP, 8-Bromo cGMP used as control due to its considerably weaker affinity for the gastrin/CCK receptor, did not compete with radiolabeled gastrin for binding to HCT 116 cells and had no effect on the morphology or proliferation in monolayer cultures of HCT 116 or CBS cells at concentrations up to 10 mM. Antigastrin/CCK antisera was also found to have dose-dependent cytostatic effects on HCT 116 and CBS cells adapted to growth in serum-free medium. The antiproliferative effect of the gastrin/CCK receptor antagonist and antigastrin/CCK antibodies suggested that a gastrin-like peptide secreted by these cells may promote growth. Radioimmunoassay of the conditioned medium of these two cell lines indicated the presence of a gastrin-like peptide (10-50 pg/10(6) cells/72 h). Northern analysis using an oligonucleotide DNA probe complementary to the nucleotide sequence coding the dodecapeptide carboxyl terminal of human gastrin showed three transcripts (0.7, 3.3, and 3.7 kb) that hybridized with the probe. These data provide, for the first time, evidence for an autocrine growth stimulatory role of a gastrin/CCK-like peptide in cultured colon tumor cells.
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PMID:Evidence for autocrine growth stimulation of cultured colon tumor cells by a gastrin/cholecystokinin-like peptide. 229 33

When dispersed chief cells from guinea pig stomach were first incubated with carbachol, washed, and then reincubated with carbachol in fresh incubation solution, the stimulation of pepsinogen secretion and the rise in intracellular calcium concentration during the second incubation were reduced. Carbachol did not cause residual enzyme secretion, but the same range of concentrations that causes enzyme secretion caused desensitization that was rapid, temperature dependent, and reversible with time. Preincubation with carbachol caused approximately a 65% reduction in enzyme secretion stimulated during a subsequent incubation with this agonist, but the potency of carbachol was unaffected. Prior exposure to carbachol also reduced subsequent stimulation caused by cholecystokinin (CCK-8), gastrin I, ionophore A23187, or 12-O-tetradecanoylphorbol 13-acetate but did not alter stimulation by any agonist that increases cellular cAMP. Carbachol pretreatment of Fura-loaded chief cells caused a threefold increase in the EC50 for carbachol-stimulated [Ca2+]i and approximately a 30% reduction in the maximal rise in [Ca2+]i in response to carbachol or CCK-8. Inhibition of [N-methyl-3H] scopolamine binding by carbachol following carbachol pretreatment indicated that modulation of receptor affinity or number did not account for functional desensitization. These data indicate that carbachol causes heterologous desensitization of pepsinogen secretion stimulated by agonists that mobilize cellular Ca2+ or activate protein kinase C through a postreceptor action and suggest that an attenuated rise in chief cell calcium is one mechanism mediating the desensitization of enzyme secretion.
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PMID:Cholinergic desensitization of pepsinogen secretion and calcium mobilization of dispersed guinea pig chief cells. 229 23

Novel aryl amide analogues of glutamic acid dialkylamide have been synthesized to test for a possible structural analogy between glutamic acid and benzodiazepine CCK antagonists such as compounds 2 and 24 (lorglumide and MK-329, respectively). In support of the structural model, certain of these hybrid compounds are more potent in pancreas CCK radioligand binding assays than corresponding lorglumide-type reference compounds. Modifications previously found in the benzodiazepine antagonists to result in brain CCK/gastrin receptor selectivity were also incorporated to produce an aryl urea series of glutamic acid analogues. None of these compounds were brain CCK/gastrin selective; however, one was potent and selective in the pancreas binding assay. The model appears to be most useful in the design of selective ligands for the pancreas type CCK receptor.
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PMID:Novel glutamic acid derived cholecystokinin receptor ligands. 229 27

For inhibition of binding of 125I-Bolton-Hunter-labeled cholecystokinin octapeptide (125I-BH-CCK-8) to guinea pig pancreatic acini, the potencies for agonists were CCK-8 greater than desulfated [des(SO3)] CCK-8 greater than gastrin-17-I greater than pentagastrin greater than CCK-4 and for the antagonists L 364718 greater than proglumide analogue 10 greater than CBZ-CCK-(27-32)-NH2. For all non-sulfated agonists, the curves were biphasic with 20% of the tracer bound to sites with high affinity for these agonists with the following relative potencies: gastrin-17-I greater than pentagastrin greater than des(SO3)CCK-8 much greater than CCK-4; whereas 80% was bound to low-affinity sites with the following potencies: des(SO3)CCK-8 greater than gastrin-17-I = pentagastrin much greater than CCK-4. For L 364718 and proglumide analogue 10, 80% of 125I-BH-CCK-8 was bound to sites with high affinity for these antagonists and 20% to sites with low affinity. Analysis of the dose-inhibition curve for CCK-8 demonstrated two binding sites; however, comparison with the analysis in the presence of 0.1 microM gastrin-17-I suggested three binding sites. The gastrin-17-I dose-inhibition curve was significantly better fit by a three-site model than by a two-site model. The affinities of the various agonists and antagonists for the three sites were compared with their abilities to inhibit binding of 125I-gastrin-I and either stimulate or inhibit CCK-8-stimulated amylase release. These results demonstrate that 125I-BH-CCK-8 binds to three classes of receptors, not two as reported previously. Two classes are CCK-preferring, bind 83% of 125I-BH-CCK-8 at tracer concentrations, and comprise high- and low-affinity CCK-preferring sites that can be distinguished by all agonists but have equally high affinity for L 364718 and proglumide 10. A third class binds 17% of the tracer, cannot be differentiated from high-affinity CCK-preferring receptors by CCK-8, and has low affinities for L 364718 and proglumide 10. Future studies relating binding of 125I-BH-CCK-8 to biological activity or characterization of the CCK receptor by using radiolabeled agonists should consider CCK interaction with three receptors, not two as was done in the past.
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PMID:Pancreatic receptors for cholecystokinin: evidence for three receptor classes. 230 86

The effect of intraduodenally administered cattle bile (CB) and Na-taurodeoxycholate (TDC) on basal pancreatic secretion and plasma levels of secretin, pancreatic polypeptide (PP), and gastrin were investigated on two separate days in 10 fasting volunteers. Doses of 2-6 g CB and 200-600 mg TDC were given intraduodenally at 65-min intervals. Volume, bicarbonate, lipase, trypsin, amylase, and bilirubin were measured in 10-min fractions of duodenal juice, and GI peptides determined by radioimmunoassay. CB and TDC enhanced significantly and dose-dependently volume, bicarbonate and enzyme secretion, and plasma secretin and PP levels. In contrast, plasma gastrin showed only a marginal increase. We conclude that the hydrokinetic effect of intraduodenal CB and TDC is at least partially mediated by secretin. Gastrin could be ruled out as a mediator of the ecbolic effect, whereas other GI peptides, primarily CCK, and/or neural mechanisms must be considered possible mediators. Both pathways may also play a role in the PP release observed.
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PMID:Effect of intraduodenal bile and Na- taurodeoxycholate on exocrine pancreatic secretion and on plasma levels of secretin, pancreatic polypeptide, and gastrin in man. 230 5

In dispersed gastric chief cells from guinea-pig stomach, binding of iodinated cholecystokinin octapeptide (125I-CCK-8) was relatively slow, temperature-dependent, to a single class of binding sites and inhibited by various gastrin- and CCK-related agonists and receptor antagonists. Binding of iodinated gastrin-I (125I-gastrin-I) was moderately rapid, temperature-dependent, to a single class of binding sites, and inhibited by various gastrin and CCK-related agonists and receptor antagonists. Gastrin-I as well as C-terminal fragments of CCK containing from eight amino acids (CCK-8) to four amino acids (CCK-4) stimulated pepsinogen secretion and inhibited binding of 125I-CCK-8 and 125I-gastrin-I. In addition, each of five different receptor antagonists inhibited binding of 125I-CCK-8 and 125I-gastrin-I and inhibited pepsinogen secretion stimulated by CCK-8 or gastrin-I. With each of eight different agonists and with each of five different antagonists the value of IC50 for inhibition of binding of 125I-CCK-8 was not significantly different from the value of IC50 for inhibition of binding of 125I-gastrin-I, indicating that in gastric chief cells the sites to which 125I-CCK-8 binds are the same sites to which 125I-gastrin-I binds. With the agonists as well as with the antagonists, however, there was no consistent relationship between the ability of a particular agent to inhibit binding and its ability to modify pepsinogen secretion, indicating that in gastric chief cells the sites that bind 125I-CCK-8 and 125I-gastrin-I are not the receptors that mediate stimulation of pepsinogen secretion by CCK-8 or by gastrin-I.
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PMID:Binding of 125I-CCK-8 and 125I-gastrin-I to dispersed chief cells from guinea-pig stomach. 232 95

Using single and double labelling techniques respectively, brain-corpora cardiaca-corpora allata complexes of the cockroach Blattella germanica have been immunohistochemically investigated with antisera raised against either the vertebrate peptide gastrin-cholecystokinin (CCK-8(s] and/or the locust neurohormone neuroparsin (NPA). Single immunolabelling with anti-CCK-8(s) reveals immunoreactive perikarya and processes in median and lateral parts of protocerebrum, optic lobes, deutocerebrum and tritocerebrum. Some fibres originating in median and lateral protocerebrum are intrinsic to the brain, whereas others terminate in the nervous areas of the corpora cardiaca. Single immunolabelling with anti-NPA reveals immunoreactive cell bodies in the median part of the protocerebrum and their processes terminate both in the nervous area of the corpora cardiaca and between the intrinsic secretory cells of this neurohaemal organ. Double immunolabelling with anti-CCK-8(s) and anti-NPA enables a description of the anatomical relations between the processes and the endings of these two neurosecretory systems.
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PMID:Gastrin-cholecystokinin-like and neuroparsin-like immunoreactivities in the brain and retrocerebral neuroendocrine complex of the cockroach Blattella germanica. 232 58

An immunocytochemical method was used for localization of various peptide-like substances in the Ascaris nervous system. Out of 45 antipeptide antisera, 12 demonstrated immunoreactivity in different subsets of neurons; these 12 antisera were raised against luteinizing hormone-releasing hormone (LHRH), Aplysia peptide L11 (L11), Aplysia peptide 12B (12B), small cardioactive peptide B (SCPB), neuropeptide Y (NPY), FMRFamide, gastrin-17, cholecystokinin octapeptide (CCK-8), alpha-melanocyte stimulating hormone (alpha MSH), calcitonin gene related peptide (CGRP), corticotropin releasing factor (CRF), and vasoactive intestinal peptide (VIP). Several peptide-like substances were colocalized to the same neuron. Our results suggest that Ascaris, like other organisms, contains multiple peptidergic systems.
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PMID:Neuropeptide diversity in Ascaris: an immunocytochemical study. 234 16

Post-natal malnutrition was induced in rats using the expanded litter model. Pepsinogen secretion of isolated gastric glands in response to several secretagogues was measured. Malnourished 19-day-old pups showed no response to carbachol, CCK-8, gastrin, secretin and ionophore A23187 compared to well-nourished animals, but showed comparable secretion of pepsinogen after stimulation with dibutyryl cAMP (DiBcAMP). Hydrocortisone treatment for 48 h caused increased pepsinogen accumulation and elevated pepsinogen secretory responsiveness to carbachol and secretin of gastric glands isolated from post-natal malnourished pups. Our results indicate that isolated gastric glands obtained from well-nourished rat possess two functionally distinct receptors for gastrin and C-terminal fragment of CCK. Our study supports the concept that in malnourished rats there is a decreased number of binding sites or/and some post-receptor defects. Pepsinogen release mechanisms remain unaffected.
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PMID:The effect of post-natal malnutrition on pepsinogen secretion receptors in weanling rats. 235 49

Continuous subcutaneous infusion of cholecystokinin (CCK-8; 5 micrograms/kg/h) to rats for 7 weeks raised the plasma CCK concentration almost fivefold and increased the pancreatic weight by about 50% but was without effect on the gastrointestinal tract. Continuous subcutaneous infusion of the CCK antagonist L-364,718 (200 micrograms/kg/h) for 7 weeks reduced the weight of the pancreas by about 30% but was without effect on the gastrointestinal tract. The effect of continuous subcutaneous infusion of CCK-8 and L-364,718 in combination was very similar to that of L-364,718 alone. Pancreaticobiliary diversion (PBD) induced a nearly 10-fold increase in the plasma CCK concentration 3 and 7 weeks after the operation. The serum gastrin values were unaffected. The weight of the pancreas was more than doubled after 7 weeks. At the same time the small intestine had gained weight, but the colon was unaffected. Continuous subcutaneous infusion of L-364,718 prevented the effect of PBD on the pancreas. On the basis of the assumption that L-364,718 is a specific antagonist of CCK, we conclude that endogenous CCK has a trophic effect on the pancreas but not on the gastrointestinal tract and that it is essential for normal pancreatic growth.
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PMID:Effects of endogenous and exogenous cholecystokinin and of infusion with the cholecystokinin antagonist L-364,718 on pancreatic and gastrointestinal growth. 235 75


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