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Query: UNIPROT:P01275 (glucagon)
 26,492 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

To produce a 125I-labelled glucagon suitable for radioligand assays, we studied the influence of variations in the lactoperoxidase iodination method. Both the degree of iodine substitution and the formation of monoiodo- or diiodo-tyrosines were pH dependent. The substitution increased and the diiodo-/monoiodotyrosine ratio decreased when pH increased. These two factors affected the immunoreactivity of the iodoglucagon relatively independently of each other. It was found that iodination at pH 10.0 with an average of 0.3 gatom I/mol glucagon resulted in 125I-labelled glucagon with higher immunoreactivity and stability than that produced at the conventional pH 7.5 and 8.5.
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PMID:Improved radioiodination of glucagon with the lactoperoxidase method. Influence of pH on iodine substitution. 0 74

A method is described whereby commercially available radioimmunoassay-grade antibodies specific for the polypeptide hormones calcitonin, gastrin, glucagon, and somotastatin are used to detect these antigens on paraffin sections of routinely fixed tissue. The hormone antibodies are applied to deparaffinized tissue sections as the primary specific immune sera using the standard peroxidase technic. The use of these hormone antibodies to detect their respective antigens has proved valuable in demonstrating polypeptide forming tumor cells in pathologic specimens.
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PMID:The utilization of radioimmunoassay antibodies for the immunohistologic staining of polypeptide hormones on paraffin-embedded tissue. 8 76

The parathyrin receptor in renal cortex has been investigated by studying the binding of 125I-labelled parathyrin, or of unlabelled parathyrin detected with 125I-labelled antibodies, to a partially purified plasma membrane fraction. The kinetics of hormone uptake demonstrated a biphasic response in both systems at 22 degrees C but this phenomenon was not detectable at 37 degrees C. Specific displacement of lactoperoxidase labelled 125I-labelled parathyrin occurred with 8 ng unlabelled bovine parathyrin. The apparent affinity constant was 2.3-10(8) M(-1) and the apparent binding capacity of the membranes 1.25 pmol/mg protein. Using the labelled antibody technique the receptor showed maximal binding at pH 7.0-7.5. As little as 80 pg bovine parathyrin produced a significant increase in binding of labelled anti-bovine parathyrin antibody and saturation of binding sites was demonstrated at 2.5 pmol/mg protein. Oxidized hormone showed undetectable binding. Treatment of membranes with phospholipases A or D, or Trypsin greatly reduced subsequent hormone binding. Prior incubation of membranes with 1-34 synthetic parathyrin decreased the binding of intact hormone whereas gastrin, insulin and glucagon had no effect. Growth hormone and calcitonin slightly increased parathyrin binding.
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PMID:Characterization of the parathyrin receptor in renal plasma membranes by labelled hormone and labelled antibody binding techniques. 17 66

In rat pancreatic islets, the glucagon-producing A-cells also contain a GIP-like material as revealed by the peroxidase-antiperoxidase immunocytochemical technique. Control studies showed that this dual staining was not due to the cross-reactivity of anti-GIP with glucagon. It is concluded either that the A-cells synthesize a GIP-like peptide or that it is taken up from the circulation.
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PMID:Immunocytochemical localization of a gastric imhibitory polypeptide-like material within A-cells of the endocrine pancreas. 33 96

The neurotensin-cell is identified immunohistochemically and ultrastructurally by differential counting of endocrine cells in the gut of a primate (Tupaia belangeri). Utilizing light microscopy, the EC-cells are identified by the Masson-Fontana silver stain; with the same method the neurotensin cells are not stained. The other endocrine cells have been quantified in the small intestine using the peroxidase-antiperoxidase stain with antisera against glucagon, somatostatin, cholecystokinin, gastrin, secretin, pancreatic polypeptide, gastric inhibitory peptide and neurotensin. In the ileal mucosa of Tupaia, the most frequent endocrine cell is the EC-cell followed by the glucagonoid cell, (L-cell). The immunoreactive neurotensin cell represents the third most frequent endocrine cell in this region. On the ultrastructural level, this third most frequent endocrine cell is a heretofore undescribed cell, the N-cell, containing electron dense secretory granules measuring 335 +/- 87 nm in diameter.
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PMID:Ultrastructural identification of a new cell type--the N-cell as the source of neurotensin in the gut mucosa. 33 60

Glucagon, insulin, somatostatin, and pancreatic polypeptide have been localized in the anolian pancreas using peroxidase-antiperoxidase immunocytochemistry. The most abundant endocrine cell type contains glucagon. Insulin-containing cells are the next most numerous. Somatostatin-immunoreactive cells tend to be localized at the periphery of the islet cords. Pancreatic polypeptide-containing cells are a minor endocrine component scattered throughout the exocrine pancreas and occasionally within the islet areas. No staining was observed after application of antigastrin serum.
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PMID:Localization of four polypeptide hormones in the saurian pancreas. 34 17

By using both immunofluorescence and peroxidase-anti-peroxidase procedures to detect cells producing the four islet hormones, supplemented by biochemical, biological, and radioimmunological assays of tissue extracts, it has been shown that insulin seems to be the most original hormone, apparently occurring already in invertebrates in cells of open type in the alimentary tract mucosa. Insulin cells also predominate in the first islet organ, namely that of the cyclostomes. The order of appearance in the endocrine pancreas during the subsequent evolution is: somatostatin; glucagon; and the pancreatic polypeptide. Even in lower vertebrates pancreatic polypeptide cells occur in those parts of the pancreas situated in close proximity to the gut.
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PMID:Immunocytochemical studies of the evolution of islet hormones. 38 30

Complementing cytochemical and ultrastructural studies, immunocytochemistry may be used to define, in terms of immunoreactivity, the nature of the polypeptide(s) made and stored in the cells of the endocrine pancreas, islet or otherwise. Immunoserums are applied to histological sections after fixation of the material in Bouin's fluid, and in accordance with four protocols: indirect immunofluorescence, immuno-enzymatic technique, variants in prolonged primary incubation and the method of soluble peroxidase-antiperoxidase complexes. Certain precautions are essential for correct interpretation. In the adult, four essential immunoreactions, corresponding to hormones or "local hormones" are regularly detected:insulin, pancreatic glucagon, somatostatin, pancreatic polypeptide. The cytochemical and ultrastructural characteristics of the cells involved are known (B, A and D cells for the first three specificities). C-peptide immunoreactivity is easily identified, but other immunoreactivities are more irregular or contested: gastrin, cholecystokinin, vasoactive intestinal peptide, ACTH, met-enkephalin.
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PMID:[Practical immunocytochemistry of the endocrine pancreas]. 39 37

An immunocytochemical technique using specific antiglucagon serum reveals the presence of glucagon-containing cells situated exclusively in the oxyntic glandular mucosa of the dog stomach. Electron microscope examination of the mucosa demonstrated endocrine cells containing secretory granules with a round dense core surrounded by a clear halo, indistinguishable from secretory granules of pancreatic A cells. Like the alpha granules of pancreatic A cells, the granules of these gastric endocrine cells exhibited a peripheral distribution of silver grains after Grimelius silver staining. Moreover, the granules of these cells were found to be specifically labeled with reaction product, using the peroxidase immunocytochemical technique at the ultrastructural level. Accordingly, these cells were named gastric A cells. These data suggest that the gastric oxyntic mucosa contains cells indistinguishable cytologically, cytochemically, and immunocytochemically from pancreatic A cells. It is believed that gastric A cells are responsible for the secretion of the gastric glucagon.
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PMID:Identification of glucagon-producing cells (A cells) in dog gastric mucosa. 77 Apr 82

Somatostatin, insulin and glucagon were localized in the principal islets of the anglerfish (Lophius americanus) and the channel catfish (Ictalurus punctata) by means of the unlabeled antibody-peroxidase-antiperoxidase immunocytochemical method. Both species showed a similar ratio of positive cells 9:6:4 (insulin:somatostatin:glucagon), but the interrelations of the three cell types differed between species. The large number of somatostatin-positive cells may be indicative of an important role for this hormone in teleost physiology. The principal islets appear to be a good source of tissue for further work on somatostatin.
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PMID:Immunohistochemical localization of somatostatin, insulin and glucagon in the principal islets of the anglerfish (Lophius americanus) and the channel catfish (Ictalurus punctata) (1) (2). 78 93


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