Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UNIPROT:P06889 (Mol)
 630,302 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The regulation patterns of gastric acid secretion in rats were investigated. Pentagastrin and histamine stimulate gastric acid secretion, but the inhibitors of DNA-dependent synthesis of RNA and of proteins prevent only the pentagastrin action. It has been found that pentagastrin induces histidine decarboxylase in gastric mucosa, ensuring local accumulation of histamine. The latter activates adenylate cyclase and results in 3',5'-AMP accumulation in gastric tissues. The administration of pentagastrin, histamine or 3',5'-AMP enhances the activity of gastric carbonic anhydrase, the enzyme which takes part in HCl formation. The data suggest that these three compounds act sequentially (pentagastrin leads to histamine leads to3',5'-AMP) and the effect of the last one could be mediated through 3',5'-AMP dependent protein kinase. The experiments in vitro demonstrated that gastric carbonic anhydrase can be separated into two isoenzymes and thephosphorylation of one of them by the 3',5'-AMP dependent protein kinase sharply increases its activity. The findings raise the possibility that histamine and 3',5'-AMP, mediating gastrin action, form together with enzymes (histidine decarboxylase, adenylate cyclase, protein kinase, carbonic anhydrase) a caascade of amplifiers. Autoradiographic studies have shown that [3H]-pentagastrin is not bound by oxyntic cells but adheres preferentially to histamine-producing alpha-like endocrine cells and to the chief cells, while 3H-histamine adheres preferentially to oxyntic and to chief cells. Electron microscopy indicates that only pentagastrin (but not histamine) initiates in alpha-like endocrine cells ultrastructural changes characteristic for induction. Pentagastrin, histamine and 3',5'-AMP administration produces in oxyntic cells ultrastructural changes typical for the secretion processes. These results lead to assumption that pentagastrin (gastrin) induces histidine decarboxylase in alpha-like endocrine cells of gastric glands. Histamine which is secreted enhances adenylate cyclase activity in the neighbouring oxyntic cells where 3',5'-AMP dependent protein kinase activates carbonic anhydrase by means of phosphorylation. These different cells form, probably, a multicellular functional unit for gastric acid secretion.
Mol Cell Biochem 1976 Sep 30
PMID:Integration of biochemical functions of different cells of rat gastric mucosa for hydrochloric acid secretion. 18 10

1. Maximal acid output after pentagastrin stimulation, and fasting and postprandial serum gastrin concentrations were determined in 25 normal subjects, 30 patients with corpus gastric ulcers, 10 patients with prepyloric ulcers and 30 patients with both duodenal and gastric ulcers. 2. Corpus ulcers and prepyloric ulcers formed one distinct group. Maximal acid output was abnormally low in the corpus ulcer patients and no different from normal in prepyloric ulcer patients, whereas fasting serum gastrin and postprandial integrated gastrin response was abnormally high in the former and no different from the normal in the latter. Furthermore, as in the normal subjects, a significant negative correlation between maximal acid output expressed in mmol h(-1) kg(-1) body weight and postprandial integrated gastrin response was observed in the corpus and prepyloric ulcer patients taken as a group. 3. In complete contrast patients with both duodenal and gastric ulcers, in whom postprandial integrated gastrin response was statistically highest amongst the three types of gastric ulcers, had a significantly positive correlation between maximal acid output and the integrated gastrin response. 4. These findings suggest the operation of different pathophysiological mechanisms in gastric ulcers with and without associated duodenal ulcers.
Clin Sci Mol Med 1978 Jul
PMID:Gastric ulcers with and without associated duodenal ulcer have different pathophysiology. 66 72

1. Prostaglandin A-, prostaglandin E- and prostaglandin F-like substances were determined radioimmunologically in antral biopsy material obtained by endoscopy. 2. In patients with gastritis, the concentrations of prostaglandin (E+A)-like substances were six times as high and of prostaglandin F-like substances twice as high as in normal subjects. In chronic atrophic gastritis, the concentrations of prostaglandin (E+A)-like material was four times as high as in normal subjects whereas prostaglandin-F like material remained unchanged. In acute gastric ulcer, prostaglandin (E+A)-like material reached concentrations four times times higher than in normal subjects, accompanied by a fivefold increase of prostglandin F-like substances. After healing of the gastric ulcer, prostaglandins returned to normal values. 3. There was no correlation between gastrin and prostaglandins in all biopsy specimens.
Clin Sci Mol Med 1977 Mar
PMID:Concentrations of prostaglandin A-, E- and F-like substances in gastric mucosa of normal subjects and of patients with various gastric diseases. 84 56

Using an immunohistochemical technique involving unlabeled antibody and the peroxidase-anti-peroxidase complex, we have localized somatostatin (or growth hormone-release inhibiting hormone), a hypothalamic hormone which can also inhibit gastrin secretion, in the rat stomach. Somatostatin was found to be present in a few cells in the mucosa of the pyloric antrum. These cells are characterized by the presence of secretory granules of about 150-250 nm in diameter and are probably endocrine cells.
Mol Cell Endocrinol 1976 Mar
PMID:Immunohistochemical localization of somatostatin in endocrine cells of the rat stomach. 126 32

1. Serum gastrin concentrations before and after a standardized meal were determined in twenty-eight patients with duodenal ulcer and in ten normal control subjects. 2. In response to pentagastrin, thirteen of the duodenal ulcer subjects secreted acid within the limits of normal and fifteen secreted in excess. 3. The differences in the basal serum gastrin concentrations between the three groups, normal subjects, acid "normosecretors" and hypersecretors were not statistically significant but that of the hypersecretors was suggestively low. 4. The integrated gastrin response and peak gastrin responses to meals were higher in duodenal ulcer patients with normal acid secretion than in the hyper-secretors but the values for the latter were not different from normal subjects. 5. Stabilization of intragastric pH by infusion into the antrum of sodium bicarbonate during the test meal response period did not alter these differences between the two ulcer patient groups. 6. A significant inverse correlation exists between the maximal acid output and the integrated gastrin response in both normal subjects and hypersecreting duodenal ulcer patients. 7. The evidence (a) supports the existence of an inverse relationship between the functioning parietal cell and gastrin cell masses, (b) shows the gastrin response in normosecreting ulcer subjects to be inappropriately high, and (c) suggests that excessive vagotonia exerts trophic effects upon both parietal cell mass and gastrin cell mass.
Clin Sci Mol Med 1976 May
PMID:The relation between functioning parietal cell and gastrin cell masses in two groups of duodenal ulcer patients. 127 45

Gastrinomas from 25 patients were examined by immunohistochemistry (IHC) and in situ hybridization histochemistry (ISH). Most patients (84%) presented with the Zollinger-Ellison syndrome. Six had multiple endocrine neoplasia type I (MEN-I). Twelve patients (48%) had duodenal primaries and 11 of 12 of these had metastases to regional lymph nodes and/or liver in spite of the small sizes of the primary tumors (mean size of 0.9 cm). Five patients had pancreatic gastrinomas and eight patients had metastatic tumor in regional lymph nodes or liver at surgery but a primary was not found. IHC and ISH analyses showed that all cases were positive for gastrin protein and 24 of 25 (96%) expressed gastrin mRNA that was easily detected in formalin-fixed, paraffin-embedded tissue sections. Both benign and malignant tumors expressed alpha subunit of human chorionic gonadotropin protein (alpha-HCG). However, only malignant gastrinomas (29%) expressed adrenocorticotropic hormone protein or proopiomelanocortin (POMC) mRNA. ISH and Northern hybridization analysis revealed that chromogranin A mRNA was the most common member of the chromogranin/secretogranin (Cg/Sg) family which was expressed in both benign and malignant gastrinomas. These results indicate that duodenal gastrinomas are common in both sporadic and MEN-1-associated cases, and small duodenal primaries may be associated with extensive regional lymph node and liver metastases. Expression of ACTH/POMC protein and mRNA was consistently associated only with malignant gastrinomas while gastrin protein, gastrin mRNA and Cgs/Sgs mRNAs were readily detected in both benign and malignant gastrinomas.
Diagn Mol Pathol 1992 Sep
PMID:Analysis of gastrinomas by immunohistochemistry and in situ hybridization histochemistry. 128 76

The present studies were directed to determine whether peptide histidine isoleucine (PHI) affects expression of the gastrin and somatostatin genes and whether such effects may be functionally linked. In separate experiments, the effects of PHI on medium gastrin and somatostatin concentrations, the incorporation of 35S-labelled amino acids into newly synthesized gastrin and somatostatin, and steady state gastrin and somatostatin mRNA were determined. PHI inhibited basal expression of the gastrin gene at all levels examined, while no significant effect on basal somatostatin gene expression could be detected. PHI also decreased carbachol-stimulated antral gastrin release and simultaneously increased somatostatin release. However, in contrast to its structural analogues, secretin and gastric inhibitory peptide, the immunoneutralization of endogenous somatostatin by the administration of specific antibodies did not affect significantly the capacity of PHI to inhibit gastrin release into the culture medium stimulated by carbachol. The results of these studies indicate that PHI exerts a physiological inhibitory effect on antral gastrin cells and that this inhibition may occur at several steps along the biosynthetic pathway. In addition, unlike its structural analogues, PHI inhibition of carbachol-stimulated gastrin release is not functionally linked to its stimulatory effects on somatostatin release.
Mol Cell Endocrinol 1992 Mar
PMID:The effects of peptide histidine isoleucine on antral gastrin and somatostatin. 135 64

Antral gastrin secretion and gene expression is inhibited by the paracrine release of somatostatin from antral D cells. Transforming growth factor-alpha and epidermal growth factor (EGF) stimulate gastrin reporter gene constructs when transfected into pituitary GH4 cells. Somatostatin inhibits EGF stimulation of gastrin gene expression, which is in part mediated at the level of transcriptional regulation as somatostatin inhibits EGF stimulation of gastrin reporter gene constructs. Somatostatin inhibition was abolished by pertussis toxin, indicating somatostatin inhibits transcription through the inhibitory G protein Gi. Somatostatin inhibition was unaffected by vanadate and okadaic acid, implying this inhibitory pathway is mediated neither through phosphotyrosine phosphatases nor serine/threonine phosphatases, respectively. Gastrin reporter genes containing 82 base pairs of the 5'-flanking DNA were sufficient to confer both EGF responsiveness and inhibition by somatostatin in GH4 cells. However, transcription of a gastrin reporter gene construct containing only the EGF response element (GGGGCGGGGTGGGGGG), located at -68 to -53, was stimulated by EGF but was not inhibited by somatostatin. Thus, somatostatin inhibits EGF-stimulated gastrin gene transcription by a mechanism other than by interfering with cell signals elicited by the EGF receptor. Since the 82 GASCAT is inhibited by somatostatin, this result also implies that sequences adjacent to the EGF response element contain a cis-regulatory element mediating transcriptional inhibition by somatostatin. This cis-element was located using gastrin reporter genes comprising sequential segments of the human gastrin promoter sequence from the transcriptional start site to -82 in the 5'-flanking DNA. Gastrin oligonucleotide constructs lacking the D oligonucleotide (gatcCATATGGCAGGGTA), located at -82 to -69 in the 5'-flanking DNA, were not inhibited by somatostatin, indicating that a somatostatin inhibitory cis-element is located between -82 and -69 in the 5'-flanking DNA of the human gastrin promoter.
Mol Endocrinol 1992 Aug
PMID:Identification of a cis-regulatory element mediating somatostatin inhibition of epidermal growth factor-stimulated gastrin gene transcription. 135 47

In colonic neoplasms, endocrine differentiation is encountered not only in carcinoid tumors but also in adenocarcinomas, where endocrine cells may represent a distinct line of differentiation in the tumor. The significance of endocrine differentiation in colorectal cancer is not well established, partly because of the paucity of tumor cell lines which can serve as a model for studying endocrine differentiation. In this report we describe the properties of NCI-H716 cells, a cell line derived from a poorly differentiated adenocarcinoma of the caecum, under various in vitro conditions and as xenografts in athymic mice. Phenotypical properties were immunohistochemically assessed using a panel of differentiation related antibodies, and also by Northern blot analysis and by electron microscopy. Receptors for biogenic amines and peptide hormones were analyzed by ligand binding assay. These studies show that: 1. NCI-H716 cells can be undifferentiated, or show endocrine, mucin-producing or "amphicrine" properties. 2. Endocrine differentiation of NCI-H716 cells preferentially occurs in xenografts in athymic mice, which suggests that mesenchymal elements induce endocrine differentiation. 3. NCI-H716 cells express large amounts of high affinity receptors for gastrin, serotonin and somatostatin and these substances can regulate growth. Thus, NCI-H716 cells form a suitable model for the study of endocrine differentiation in intestinal epithelium and of auto- or paracrine growth regulation in intestinal neoplasia.
Virchows Arch B Cell Pathol Incl Mol Pathol 1992
PMID:NCI-H716 cells as a model for endocrine differentiation in colorectal cancer. 135 4

Messenger RNA for rat islet amyloid polypeptide (IAPP) has been identified not only in the pancreas but also, in lesser amounts, in preparations from the stomach and dorsal root ganglia. In the stomach, insulin mRNA was not detectable, ruling out possible contamination by pancreatic tissue. Because IAPP and calcitonin gene-related peptide (CGRP) are related and CGRP is present in both stomach and dorsal root ganglia, it was possible that 'IAPP' signals were in fact due to cross-hybridization with CGRP mRNA. A second IAPP probe was constructed which does not cross-react. This probe also detected mRNA in both tissues, confirming the expression of IAPP in both tissues. The regional distribution of IAPP mRNA in the stomach did not parallel that of gastrin mRNA. IAPP mRNA was present in the antrum, centrum and pylorus and, like gastrin, the highest amounts were in the pylorus. However, the ratio between the pylorus and centrum was 3.6:1 for IAPP and 156:1 for gastrin. The effects of dietary manipulation were determined; a period of 48 h of starvation reduced pancreatic IAPP mRNA by approximately 60%, whereas in the stomach there was no significant reduction. If the action of IAPP was hormonal, pancreas and stomach would not be acting in concert. A paracrine role for gastric IAPP therefore seems more likely.
J Mol Endocrinol 1992 Oct
PMID:Extra-pancreatic expression of the rat islet amyloid polypeptide (amylin) gene. 141 86


1 2 3 4 5 6 7 8 9 10 Next >>