Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P01275 (glucagon)
 26,492 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

After a review on the historical development of morphological investigations of entero-endocrine cells, dating back to 1870, a detailed synoptical review of the current stage of findings in this field is given. At the present time nine different endocrine cell types can be distinguished in the epithelium of the gastrointestinal tract. Criteria for this differentiation are properties concerning specific staining methods, aldehyde-induced fluorescence, immunohistochemistry, and ultrastructure. From present results it is obvious that distinct cell types are responsible for the synthesis of defined polypeptide hormones (e.g. gastrin, secretin, enterogastrone). The metabolism of amines, in relation to the endocrine cells of the gastrointestinal tract is of particular interest here. Points investigated include the uniqueness of endocrine cells, with regard to the metabolism of biogenic amines ("APUD-cells") and the possibility of serotonin synthesis by a definite cell type, i.e. by the EC-cell ("enterochromaffin" cell). In our experimental animal, male Wistarrats, seven different entero-endocrine cell types can be discerned by ultrastructural means: EC-, ECL-, G-, AL-, EG-, D- and D1-cells. The I-cell (found in other species) can hardly be distinguished from the AL-cell by ultrastructural means and the S-cells, as found in other species, are not to be found at all. Only some of the cited cell types can be seen by fluorescence microscopy. After formaldehyde-treatment of the tissue, the "enterochromaffin" cell shows a yellow, serotonin-specific fluorescence. This cell corresponds in shape, number and distribution to the ultrastructurally defined EC-cell. EC-cells are found predominantly in the pyloric region and the duodenum and less frequently in the middle- and hindgut and the cardiac region; seldomly EC-cells are encountered in the oxyntic gland area of the stomach. In the rat gastro-intestinal tract, number and fluorescent intensity of EC-cells does not always correspond with the serotonin content of a certain region--sometimes the level of serotonin is largely determined by the mast cells, which in the rat also contain serotonin. For example, the high serotonin content of the oxyntic gland area, which contains very few EC-cells, has to be contributed nearly exclusively to mast cell serotonin. Mast cells can be domonstrated by fluorescence microscopy, due to their histamine content, after treatment of the tissue with o-phthalaldehyde (OPD). It seems likely that the histamine content, especially that of the so-called "atypical mast cells" of the mucosa, is inversely related to their respective serotonin content. --In addition to mast cells, OPD-treatment leads to a fluorescence in some of the entero-endocrine cells of the gastrointestinal epithelium. In the gastric epithelium these fluorescing cells should be regarded as histamine-containing ECL-cells and glucagon-containing AL-cells while in the colonic epithelium they are considered to be glucagon-containing AL-cells...
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PMID:[The endocrine cells of the gastrointestinal epithelium and the metabolism of biogenic amines in the gastrointestinal tract (author's transl)]. 13 9

With combined immunofluorescent, cytochemical and electron microscopic investigations the enterochromaffin cell system has been differentiated into 5 distinct endocrine cell types in the human stomach and into 8 cell types in the intestine. These endocrine cells are probably of neuroectodermal origin and belong to the APUD (amine precursor uptake and decarboxylation)-system. Maximal gastrointestinal hormone concentrations as determined by tissue extracts correlate fairly well to the location of each endocrine cell type in various segments of the gastrointestinal tract. In certain gastroenteropathies the pathophysiological disturbances can be explained by pathomorphological alterations of the disseminated endocrine cells. 1. The gastrin-producing G-cell is the predominating endocrine cell in the gastric antrum. Besides immunocytochemistry the G-cell can be demonstrated with argyrophilic reaction (Grimelius, 1968), masked metachromasia and leadhematoxylin. The ultrastructural features are variable, depending on functional activity. The secretory granules are usually only slightly osmiophilic, measuring 200 till 250 nm in diameter. By some working groups a positive immunofluorescence with gastrin-antisera has been demonstrated in A1- or D-cells of the pancreatic islets. However, numerous negative results have been reported, too. Considering physiological conditions, a gastrin-secretion of the human pancreatic islets has not been secured without doubt. 2. The EC-cell produces serotonin and in the intestine motilin, too. Besides the formaldehyde-induced fluorescence, these cells can be demonstrated with diazonium and argentaffin reactions, less specific with argyrophilic methods. Ultrastructurally the EC-granules are easily differeniated from the other endocrine cells by their pronounced osmiophilia and pleomorphism. In experimental conditions the EC-cells demonstrate species- and site-specific alterations. With reserpine no ultrastructural changes were demonstrable in EC-cells of the rat. However, marked ultrastructural alterations with an increase of the hormone-producing organelle system were noticed after administration of parachlorophenylalanine (PCPA) which interferes with serotonine synthesis; 5. The gastric D-cells are characterized by large secretory granules similar to pancreatic D-cells. They secrete the HCl-inhibitory peptide somatostatin. 4. The D1-cell is a cell type with unknown function. The cytoplasm contains small granules with variable electron density. According to most authors, they represent a distinct cell type and not just a variant of the G-cells. It may be very difficult, however, to separate certain forms of D1-cells from functionally altered G-cells. 5. The A-cell can be found in the gastric mucosa of certain animal species, where it has been demonstrated by immunocytochemistry with antisera to gut-glucagon. This cell type does not occur in the human gastric mucosa. 6...
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PMID:[Pathomorphologic studies of the endocrine cells in the gastrointestinal mucosa. Physiology, cytochemistry and ultrastructure (author's transl]. 19 Aug 18

Using indirect immunofluorescence, indirect immunoperoxidase, and unlabelled antibody enzyme techniques, gastrin, pancreatic glucagon, insulin, and somatostatin were localised in sections of both wax- and resin-embedded tissues that had been fixed in a buffered formalin solution. Ultrastructural preservation of the resin-embedded samples was also adequate for combined electron microscopy and light microscope immunochemistry. As the fixative concerned is stable it can be permanently available in surgical units. It is suggested, therefore, that this fixative should prove useful as an alternative to buffered formaldehyde, which must be freshly prepared from paraformaldehyde powder, in institutions where specimen collection is difficult or which have to refer cases with an endocrine involvement to other laboratories for immunochemical and fine structural examination.
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PMID:A formalin fixative for immunochemical and ultrastructural studies on gastrointestinal endocrine cells. 37 49

Strong secretin-like immunofluorescence has been demonstrated in endocrine-like cells from the gastric epithelium of Styela. These cells also stain with lead haematoxylin and exhibit a brilliant formaldehyde-induced fluorescence, but do not show any other cytochemical features characteristics of the mammalian APUD series. Tests with antisera to glucagon, gastrin and somatostatin all proved negative. In the oesophagus tests with all four antisera proved negative. The significance of these results is discussed in relation to the phylogeny of vertebrate gastro-intestinal hormones.
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PMID:A cytochemical and immunofluorescence study of endocrine cells in the gut of the ascidian Styela clava. 46 92

Treatment with formaldehyde gas and HCl vapor, simultaneously or in sequence, induces fluorescence with indoles, including tryptophan residues of peptides, as is evident from studies on protein droplet models. Among cells that display intense formaldehyde-HCl-induced fluorescence are pancreatic exocrine cells, gastric chief cells, Paneth cells and enterochromaffin cells. Peptide hormone-producing cells that can be visualized by the formaldehyde-HCl treatment include gastrin cells and glucagon cells. The simultaneous procedure has proved superior to the sequential procedure. Simultaneous formaldehyde-HCl treatment appears to be a useful method for the demonstration of tryptophan residues of peptides and proteins. It seems more sensitive than previously described indole methods.
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PMID:Formaldehyde-hydrochloric acid treatment. A fluorescence histochemical method for the demonstration of tryptophan residues in peptides and proteins. 110 7

Recent results have demonstrated altered corticotropin-releasing factor (CRF)-41 content of the neurointermediate lobe (NIL) of the pituitary gland in response to various manipulations including osmotic stimulation. This study was undertaken to determine whether changes in CRF-41 content of the NIL are accompanied by changes in intensity of CRF-41-like immunoreactivity (CRF-41-LI) of neurosecretory neurones of the hypothalamus in response to osmotic stimulation. Wistar rats of both sexes given either tap water ad libitum, 2% NaCl solution, or access to tap water was limited to 20 min daily, for 7 days. Subsets of rats from each group were adrenalectomized (ADX) or treated with dexamethasone (DEX). Thirty-six hour before perfusion with fixative consisting of buffered formaldehyde and picric acid, animals received 75 micrograms colchicine i.c.v. Forty micrometer thick vibratome sections were stained for CRF-LI, arginine vasopressin (AVP-LI) and oxytocin (OXY-LI) using the avidin-biotin-peroxidase complex method. In response to both types of osmotic stimulation magnocellular neurones of the paraventricular (PVN) and supraoptic nuclei (SON) showed increased CRF-LI, AVP-LI and OXY-LI, while CRF-LI of parvocellular perikarya of the PVN decreased. The enhanced CRF-LI seemed to appear in a subset of magnocellular neurones with OXY-LI but not AVP-LI. Increased staining intensities were also observed in magnocellular neurones in ADX rats challenged osmotically. In contrast, systemic DEX administration, as well as implantation of DEX in the area on the SON, sharply attenuated CRF-LI but not AVP-LI or OXY-LI of magnocellular neurones in osmotically stimulated rats.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Oxytocinergic neurons in rat hypothalamus. Dexamethasone-reversible increase in their corticotropin-releasing factor-41-like immunoreactivity in response to osmotic stimulation. 211 29

The identity of monoamine-emitted, formaldehyde-induced fluorescence in some pancreatic islet cells was studied in pancreatic tissue of male chickens by fluorescence and immunohistochemistry either on the same tissue section or on serial tissue sections. Pancreatic islet cells emitting intense formaldehyde-induced fluorescence also react immunohistochemically with antisera directed against glucagon, serotonin and aromatic L-amino acid decarboxylase. These results show that chicken pancreatic islet A cells contain glucagon, serotonin, and aromatic L-amino acid decarboxylase, an enzyme involved in the synthesis of serotonin. The islet B cells identified with anti-insulin immunoreactivity, which displayed a very weak formaldehyde-induced fluorescence, did not react with anti-serotonin serum.
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PMID:Immunohistochemical colocalization of glucagon, serotonin, and aromatic L-amino acid decarboxylase in islet A cells of chicken pancreas. 240 8

Available techniques for light and electron microscopical double immunocytochemical staining are all associated with certain problems. We have developed a novel multiple staining procedure, which allows use of antibodies of differing specificities, raised in the same species (e.g. rabbit). Its essential features include 1) saturation of antigenic epitopes on the first layer primary antiserum by second (fluorophor- or gold-) labelled anti-IgG antibodies and 2) denaturation of free anti-IgG binding sites by formaldehyde vapour treatment. Various combinations of gastrin, somatostatin, glucagon, ACTH, growth hormone and enkephalin/endorphin antibodies have been tested at the light and electron microscopical level and have been found to give highly reproducible double- and triple-staining results. The technique has also been evaluated by use of cytochemical paper models. The method is simple and very useful for multiple staining of a wide variety of antigens.
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PMID:Simultaneous demonstration of multiple antigens by indirect immunofluorescence or immunogold staining. Novel light and electron microscopical double and triple staining method employing primary antibodies from the same species. 241 88

In situ hybridization with 35S-labeled single stranded RNA probes was used on sections from formaldehyde-fixed and paraffin-embedded tissue specimens to provide semiquantitative data on the occurrence of transthyretin(TTR)-mRNA in human liver, choroid plexus and pancreatic islets as well as in 15 endocrine tumours of the pancreas and gut. A monoclonal antibody to TTR was used for immunocytochemical identification of the protein in consecutive sections. The amount of TTR-mRNA in hepatocytes was found to be much less than that in epithelial cells of the choroid plexus. Glucagon cells of the pancreatic islets were also specifically labeled and the level of TTR-mRNA in these cells was intermediate between that of hepatocytes and choroid plexus epithelial cells. Four glucagonomas, one malignant insulinoma and two midgut carcinoids were shown to contain TTR-mRNA. The 'in situ' labeled cells were also found to be TTR immunoreactive. These findings present the first conclusive evidence for TTR synthesis in pancreatic islets and in endocrine tumours. They also establish that the high serum concentration of TTR found in some patients with endocrine tumours (notably glucagonomas) is most likely due to tumour production of TTR.
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PMID:In situ localization of transthyretin-mRNA in the adult human liver, choroid plexus and pancreatic islets and in endocrine tumours of the pancreas and gut. 265 58

Differentiated teratomas frequently contain the apparent equivalent of gastrointestinal mucosa. 53 testicular teratomas were investigated for the incidence of entero-endocrine cells. Enterochromaffin(EC)-cells were demonstrated by formaldehyde induced fluorescence (FIF), while the other endocrine cells were identified by immunohistochemistry. 11 of 53 teratomas contained endocrine cells associated with the gastrointestinal epithelium. The most frequently found cell type was the EC-cell, followed by somatostatin-, glucagon- and pancreatic polypeptide-immunoreactive cells. The teratoma tissue blocks (20 of 53) also frequently exhibited normal testicular tissue which did not contain any EC-cell or other entero-endocrine cells. The results are of interest in considering the cytogenesis of entero-endocrine cells and the histogenesis of testicular carcinoids, indicating that the entero-endocrine cells derive from the intestinal carcinoids, indicating that the entero-endocrine cells derive from the intestinal epithelium arising from undifferentiated stem cells. Furthermore, it seems probable that primary testicular carcinoids can develop from pre-existent teratomas by proliferation of their entero-endocrine cells.
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PMID:Endocrine GEP-cells in primary testicular teratoma. 610 1


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