Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P00790 (PGA)
 2,475 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Metiamide, 25 mg, antagonized the action of histamine on acid and pepsin secretion from both denervated pouches and innervated stomachs in dogs. In the same preparations its action on pepsin following food, pentagastrin or 2 deoxy-d-glucose was nonsignificant. Following pilocarpine or secretin, metiamide augmented pouch pepsin. The action of every acid stimulant was depressed by metiamide including the direct vagal action of deoxy-d-glucose on the innervated stomach. H2 receptors seem, therefore, to be involved in some form in acid stimulated by the vagi, histamine, pentagastrin and pilocarpine. Pepsin stimulation does not seem to be via H2 receptors with the esception of stimulation by histamine itself.
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PMID:Metiamide: an antagonist of histamine-stimulated gastric acid secretion. 5 35

1. The serum gastrin level, gastric mucosal blood flow and acid secretion from the canine Heidenhain pouch have been measured in response to the introduction of bovine serum albumin, pepsin-digested albumin, an amino acid mixture, liver extract and mannitol used as control. 2. Distention of the Heidenhain pouch with mannitol or albumnin at pH 5-0 produced a similar pressure-related increase of acid secretion reaching a peak of only 10 percent of the maximal response to histamine. Pepsin-digested albumin was capable of producing larger acid outputs than undigested albumin. The highest acid output, attaining about 80 percent of the maximal response to histamine, was obtained with liver extract both before and after exhaustive dialysis to remove all the amino acids and short peptide fragments. An amino acid mixture containing all essential amino acids was also found to stimulate acid secretion but a lesser degree than liver extract. 3. This concluded that it is not the intact protein but the products of its digestion, the polypeptides and free amino acids, which are potent chemical stimulants of acid secretion from the oxyntic gland area. Since the serum gastrin level was not changed during acid secretion induced by peptic digests bathing the oxyntic gland area, the mechanism of chemical stimulation appears to be gastrin-independent. 4. The response to chemical stimulation by peptic digests can be greatly potentiated by combining this with distention of the oxyntic gland area. Topical application of xylocaine or atropine causes a marked decrease of Heidenhain pouch response to peptic digests, suggesting a possible neural reflex component in the mechanism of chemical stimulation of the oxyntic gland area. 5. When the pH of the liver extract in the Heidenhain pouch was gradually decreased in sequential order from 5-0 to 1-0, this resulted in a pH-related decrease in acid secretion and in the mucosal blood flow falling to the basal level at pH 1-0. Exogenous secretion given in graded doses from 0-5 to 8-0 u./kg. hr caused a small but dose-related inhibition of acid response to liver extract accompanied by a decrease of mucosal blood flow but without any significant change in the serum gastrin level. 6. The results indicate that the chemical stimulation of the oxyntic gland area by peptic digests is capable of inducing acid secretion by a local, gastrin-independent, partially neural reflex mechanism; sensitive to pH, pressure and secretin.
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PMID:Chemical stimulatory mechanism in gastric secretion. 23 20

H+ and pepsin output were studied in four gastric fistula dogs with histamine and in five dogs with 4-methylhistamine (4(Me)H), an H2 histamine receptor agonist with little H1 effect. Each amine was given in 45-min incremental step doses to constitute full dose-response curves. Pepsin output was biphasic with both drugs. Peak pepsin output occurred at low doses (less than or equal to 5 microgram/kg-h) and progressive inhibition of output was seen at higher doses, but H+ output was stimulated at all doses. The H2 receptor antagonist, cimetidine, competitively inhibited H+ stimulation. The pepsin response to histamine or 4(Me)H was converted to a positive logsigmoid response when cimetidine was given at the same time. In the presence of cimetidine (1 mg/kg-h), the outputs of H+ and pepsin were positively correlated in the full histamine dose range. These data show that histamine effects on pepsin secretin are a mixture of stimulation and inhibition and that the receptor responsible for pepsin stimulation is of a high affinity, low Km, H2 type, whereas inhibition at high doses of histamine is probably mediated by a low affinity, high Km receptor, also H2 type.
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PMID:Evidence for a histamine H2 receptor that inhibits pepsin secretion in the dog. 33 42

When maintained in organ culture, rabbit gastric mucosal biopsies incorporated [14tc]leucine into tissue protein and secreted labeled protein into culture medium steadily for 24 hr. Incorporation of radioactivity was abolished by cycloheximide. When examined by sodium dodecyl sulfate gel electrophoresis, dextran gel filtration, and ion exchange chromatography, 65 to 90% of macromolecular radioactivity secreted into culture medium migrated coincidentally with enzymatically assayed pepsinogen. Pepsin activity in cultured biopsies did not decrease during 24 hr of organ culture. Nevertheless, pepsin activity increased linearly in culture medium during this period. Acetylcholine markedly stimulated secretion of labeled protein and pepsinogen by cultured biopsies. In the presence of a subthreshold concentration (10(-10) M) of acetylcholine, pentagastrin, secretin, and the octapeptide of cholecystokinin, all stimulated protein secretion. Over-all incorporation of [14C]leucine into protein by cultured biopsies was stimulated by 10(-9) M pentagastrin. These results directly demonstrate: (1) synthesis and secretion of protein and pepsinogen by isolated gastric mucosa, (2) stimulation of gastric secretion of protein by acetylcholine and polypeptide hormones, and (3) stimulation of gastric synthesis of protein by pentagastrin.
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PMID:Synthesis and secretion of protein and pepsinogen by rabbit gastric mucosa in organ culture. 109 89

The effect of secretin on acid and pepsin secretion and gastrin release in the totally isolated vascularly perfused rat stomach was studied. With the phosphodiesterase inhibitor isobutyl methylxanthine (IMX) added to the vascular perfusate, baseline acid secretion was 4.7 +/- 1.1 (mean +/- S.E.M.) mumol/h and baseline pepsin output 1147 +/- 223 micrograms/h. Secretin significantly inhibited acid output to a minimum of 1.4 +/- 0.2 mumol/h at a concentration of 25 pM in the vascular perfusate (P less than 0.01). Pepsin output was not significantly different from baseline at any of the secretin doses tested. Threshold secretin concentration for acid inhibition was 5 pM. IMX stimulated gastrin output from 48 +/- 9 pM in the basal state to 95 +/- 13 pM after IMX (P less than 0.01). Secretin inhibited gastrin release only at the maximal dose of 625 pM, when gastrin concentration in the venous effluent decreased from 93 +/- 19 to 68 +/- 19 pM after secretin. Thus, in the totally isolated vascularly perfused rat stomach secretin in physiological concentrations inhibits acid secretion by a direct action on the acid secretory process and not via gastrin inhibition. The study also suggests that gastrin release at least in part is mediated via increased intracellular cAMP.
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PMID:The effect of secretin on acid and pepsin secretion and gastrin release in the totally isolated vascularly perfused rat stomach. 243 26

Valosin, a novel 25-amino acid gastrointestinal peptide with N-terminal valine and C-terminal tyrosine, has recently been isolated from porcine upper gut extracts. Its physiologic role is unknown and it does not belong to one of the structurally related gut peptide families. Assuming that valosin may influence gastrointestinal functions, we investigated the effect of high-performance liquid chromatography-pure valosin on gastric and exocrine pancreatic secretion and on the intestinal myoelectric activity in conscious dogs. Intravenous injection of valosin (0.125-1 microgram/kg) dose-dependently increased gastric acid secretion 80-fold over basal, corresponding to 18% of the maximal pentagastrin-induced effect. Pepsin output increased 10-fold over basal (30% of the pentagastrin-stimulated secretion). Half-maximal stimulation by pentagastrin could be further increased dose-dependently by simultaneous administration of valosin. Pancreatic bicarbonate secretion was stimulated 11-fold over basal at 1.0 microgram/kg, reaching about 6% of the secretin-induced maximal output, whereas protein secretion increased 12-fold over basal, corresponding to about 55% of the cholecystokinin-induced maximal output. In fasted dogs, spontaneously occurring migrating myoelectric complexes were substantially delayed during infusion of valosin at a dose of 0.2 microgram/kg. These experiments indicate that valosin may represent a novel member of the regulatory gastrointestinal peptides.
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PMID:Valosin stimulates gastric and exocrine pancreatic secretion and inhibits fasting small intestinal myoelectric activity in the dog. 310 27

In a radioassay for Vasoactive Intestinal Peptide (VIP)-binding, eight out of 33 plasma samples from healthy human subjects exhibited specific binding ranging from 2.6% to 46.7% of total [125 I]VIP. This binding was competitively displaced by unlabeled VIP. The structurally homologous peptides, Peptide Histidine Isoleucine (PHI) and secretin, were, respectively, 72-fold and 413-fold less potent than VIP in displacing bound [125 I]VIP, whereas the unrelated peptides, neurotensin, eledoisin, bombesin and metenkephalin, were without effect on the binding. The antibody nature of the VIP-binding factor was suggested by its precipitation with ammonium sulfate, attenuation after absorption with Staphylococcus aureus preparations, precipitation with antisera against human IgG and IgM, and coelution with standard IgG and IgM on anion-exchange and high-performance gel-filtration columns. Pepsin treatment of purified IgG fraction yielded a VIP-binding species with apparent molecular weight of 108 +/- 13 kDa that was precipitated by antiserum against the F(ab)2 fragment of the IgG molecule. These results demonstrate the existence in some human plasmas of an autoantibody that binds VIP.
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PMID:Autoantibody to vasoactive intestinal peptide in human circulation. 383 70

In eight volunteers the effect of pentagastrin (0.15, 1.0 and 6.0 microgram/kg body weight/h), secretin (0.5 and 1.0 clinical units/kg b.w./h), and cholecystokinin (CCK) (0.5 and 1.0 Ivy dog units/kg b.w./h) on the gastric secretion of pepsin was investigated to ascertain whether interaction occurred. A high intraindividual variation was found, and also a significant washout of pepsin in the initial period after stimulation. Pepsin secretion was stimulated after pentagastrin (50% above basal level) and even more after secretin (75%-200% above basal level), whereas no stimulation but a tendency for depression was seen after CCK. With the doses of gastrointestinal hormones used in this investigation, no interaction between secretin and CCK on gastric secretion of pepsin in man was demonstrated.
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PMID:Effect of Pentagastrin, secretin, and cholecystokinin on gastric secretion of pepsin in man. 679 45

The linear homopolymer poly-beta-1,6-N-acetyl-D-glucosamine (beta-1,6-GlcNAc; PGA) serves as an adhesin for the maintenance of biofilm structural stability in diverse eubacteria. Its function in Escherichia coli K-12 requires the gene products of the pgaABCD operon, all of which are necessary for biofilm formation. PgaC is an apparent glycosyltransferase that is required for PGA synthesis. Using a monoclonal antibody directed against E. coli PGA, we now demonstrate that PgaD is also needed for PGA formation. The deletion of genes for the predicted outer membrane proteins PgaA and PgaB did not prevent PGA synthesis but did block its export, as shown by the results of immunoelectron microscopy (IEM) and antibody adsorption assays. IEM also revealed a conditional localization of PGA at the cell poles, the initial attachment site for biofilm formation. PgaA contains a predicted beta-barrel porin and a superhelical domain containing tetratricopeptide repeats, which may mediate protein-protein interactions, implying that it forms the outer membrane secretin for PGA. PgaB contains predicted carbohydrate binding and polysaccharide N-deacetylase domains. The overexpression of pgaB increased the primary amine content (glucosamine) of PGA. Site-directed mutations targeting the N-deacetylase catalytic activity of PgaB blocked PGA export and biofilm formation, implying that N-deacetylation promotes PGA export through the PgaA porin. The results of previous studies indicated that N-deacetylation of beta-1,6-GlcNAc in Staphylococcus epidermidis by the PgaB homolog, IcaB, anchors it to the cell surface. The deletion of icaB resulted in release of beta-1,6-GlcNAc into the growth medium. Thus, covalent modification of beta-1,6-GlcNAc by N-deacetylation serves distinct biological functions in gram-negative and gram-positive species, dictated by cell envelope differences.
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PMID:Roles of pgaABCD genes in synthesis, modification, and export of the Escherichia coli biofilm adhesin poly-beta-1,6-N-acetyl-D-glucosamine. 1835 7