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)

The immunohistochemical detection of six distinct sequences of proglucagon and its derivatives (GRPP, glicentin, glucagon-37, glucagon-29, GLP1, GLP2 and MPGF) in both intestinal L cells and pancreatic or gastric A cells of some mammals (dog, man, guinea pig) confirms that the two cell types produce the same proglucagon molecule, although the final step of its post-translational processing differs in the two cells. Immunohistochemical and ultrastructural patterns of glucagon/glicentin cells in the pancreas of lower vertebrates and early human fetuses, as well as tumor cell studies, suggest an evolution of gastropancreatic A cells from L cells. On the contrary, the PP-related peptide PYY of intestinal L cells, and PP with its C-terminal icosapeptide extension of pancreatic PP cells, likely originate from different prohormones. Although intermediate patterns of peptide expression can be observed, including some F-type PP cells of the dog pancreas (uncinate process) and pyloric mucosa showing PYY immunoreactivity or rare PYY and/or HPP immunoreactive cells of the human rectum lacking glicentin reactivity, no obvious relationship can be established between L cells and pancreatic (F-type) PP cells. However, some evolutionary, embryogenetic and oncogenetic link may exist between L cells and human D1-type PP cells, a minor population of PP cells scattered in the pancreatic tissue of dorsal pouch origin and a major fraction of tumor PP cells.
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PMID:Glucagon- and PP-related peptides of intestinal L cells and pancreatic/gastric A or PP cells. Possible interrelationships of peptides and cells during evolution, fetal development and tumor growth. 384 89

A common feature in the phylogeny of the four islet hormones (insulin, somatostatin, glucagon, PP) is that they do not seem to occur in the most primitive metazoan animals investigated so far, namely the coelenterates. However, already in the earliest protostomian invertebrates, such as flatworms and annelids, somatostatin and PP immunoreactive nerve fibres were found. In highly developed forms of protostomian invertebrates, such as insects, all the four islet hormones are represented as immunoreactive nerve cells and nerve fibres in the brain. In deuterostomian invertebrates a brain-gut-axis has evolved as regards somatostatin and PP, whereas insulin and glucagon now seem to occur exclusively as cells of open type in the gut mucosa. This brain-gut-axis for somatostatin and PP persists in all the vertebrates. The insulin cells, however, leave the gut mucosa already in the earliest forms of vertebrates and then appear only as cells in the islet parenchyma and in the mucosa of the bile duct (Agnatha) or in the pancreatic ducts (Gnathostomi). To some extent, glucagon islet cells evolve in a similar manner; here, however, cells immunoreactive with the precursor hormone, glicentin (enteroglucagon), persist in the gastrointestinal tract mucosa. A few PYY immunoreactive cells have been found in the pancreatic islet parenchyma of reptiles and mammals, often as disseminated cells in the acinar tissue. In the pancreas of these phyla NPY only occurs in neurons and nerve fibres. In pilot studies the effects of hagfish insulin as a growth factor have been compared with those of pig insulin on Swiss 3T3 mouse embryonic fibroblasts.
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PMID:Phylogenetical aspects on islet hormone families: a minireview with particular reference to insulin as a growth factor and to the phylogeny of PYY and NPY immunoreactive cells and nerves in the endocrine and exocrine pancreas. 391 9

Pancreatic endocrine cells were stained immunocytochemically for insulin, glucagon, somatostatin and pancreatic polypeptide by the PAP technique or sequentially for two hormones by the PAP followed by an indirect immunogold procedure. Pancreatic endocrine cells of Chrysemys are found scattered as single cells or small aggregates throughout the exocrine parenchyma; only the splenic region shows islets consisting of a B cell core surrounded by a loose mantle of A cells and occasional D cells. PP cells were not found in this splenic portion but were found scattered throughout the remainder of the pancreas. In contrast to the typical vertebrate islet, Chrysemys pancreatic endocrine cells are characterized by a lack of preferential association of one cell type with another and suggests that paracrine regulatory mechanisms may not be operable in this species. Insulin secretion from pieces of Chrysemys pancreas has been measured in incubation and perifusion systems employing a heterologous radioimmunoassay. Insulin release by Chrysemys B cells is enhanced by elevated levels of glucose (300 mg/dl), however, response appears to be somewhat slower compared to other vertebrate B cells. Gastrin, secretin, neurotensin, motilin, serotonin, PYY, glucagon, gastric inhibitory polypeptide, somatostatin and insulin were demonstrated immunocytochemically in open-type GEP cells of the mucosal epithelium of the Chrysemys intestine. Of these cells, gastrin, neurotensin and insulin cells appear to be the most numerous while the other types appear less frequently. Cells containing PP, bombesin, cholecystokinin and substance P could not be demonstrated. The localization of insulin to GEP cells of the turtle intestine is an unusual finding but has been confirmed by radioimmunoassay of extracts of the intestinal mucosa.
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PMID:The gastro-entero-pancreatic system of the turtle, Chrysemys picta. 391 12

Endocrine-like cells containing glucagon, glicentin or pancreatic polypeptide immunoreactivity in human foetal and adult stomach, with or without disease, were studied with the indirect immunoperoxidase method and mirror sectioning technique. In foetal and neonatal oxyntic mucosae, there were endocrine-like cells with glucagon and glicentin immunoreactivities and argyrophilia. Cells containing glicentin immunoreactivity alone were detected earlier than glucagon cells during foetal development, and were also distributed throughout foetal to neonatal life. Bovine pancreatic polypeptide immunoreactivity coexisted in a subpopulation of the glucagon-glicentin cells. These cells were absent from normal oxyntic mucosa in the postneonatal period and from normal antral mucosa throughout life. Hamartomatous polyp in adult oxyntic mucosa, hyperplastic oxyntic mucosa in Menetrier's disease and atrophic oxyntic mucosa in a remnant stomach with cancer showed scattered glucagon-glicentin cells, but few or no cells containing bovine pancreatic polypeptide. Intestinalized mucosa showed plentiful glicentin cells with occasional glucagon and/or bovine pancreatic polypeptide immunoreactivity. Some gastric cancer cells of both diffuse and adenoplastic types contained immunoreactive glicentin and, less frequently, glucagon. Bovine pancreatic polypeptide immunoreactivity was detected in a few adenoplastic cancer cells, but not in diffuse type cells. Three different anti-pancreatic polypeptide sera against bovine, porcine or human pancreatic polypeptide detected basically the same cells mentioned above, but pancreatic polypeptide cells lacking human pancreatic polypeptide immunoreactivity were also present in foetal oxyntic mucosa. Immunoabsorption tests revealed that the bovine pancreatic polypeptide immunoreactivity was remote from peptide YY and neuropeptide Y.
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PMID:Immunohistochemical studies on glucagon, glicentin and pancreatic polypeptide in human stomach: normal and pathological conditions. 620 42

In this study we report the localisation of PYY immunoreactivity in intestinal mucosa endocrine (EG) cells containing glucagon-related peptides and also in foetal pancreatic A cells of rat and man. Radioimmunoassay of human foetal pancreatic extracts revealed the presence of PYY immunoreactivity, the concentration of which declined with age (from 65.42 pmol/g at week 20 to 17.0 pmol at week 40; correlation coefficient = -0.893), in contrast to the amount of glucagon which remained statistically constant throughout the same foetal period. The identity of this PYY immunoreactive material with the original 36 amino acid porcine peptide has been shown by high pressure liquid chromatography (HPLC).
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PMID:Peptide YY (PYY) immunoreactivity is co-stored with glucagon-related immunoreactants in endocrine cells of the gut and pancreas. 638 52

Endocrine cells containing peptide YY (PYY) were numerous in the rectum, colon and ileum and few in the duodenum and jejunum of rat, pig and man. No immunoreactive cells could be detected in the pancreas and stomach. Coexistence of PYY and glicentin was revealed by sequential staining of the same section and by staining consecutive semi-thin sections. Since the PYY sequence is not contained in the glucagon/glicentin precursor molecule the results suggest that the PYY cell in the gut expresses two different genes coding for regulatory peptides of two different families.
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PMID:Coexistence of peptide YY and glicentin immunoreactivity in endocrine cells of the gut. 654 68

Naturally occurring peptides with biological actions have in most cases been detected by observing their biological activities in crude extracts and their isolation has been followed using bioassays. As a complement to the classical biological detection systems, we have proposed a chemical detection system based on fragmentation of peptides in tissue extracts followed by identification of certain of these peptide fragments having distinct chemical features. One such chemical feature is the C-terminal amide structure which is characteristic of many biologically active peptides. We have devised a chemical assay method for peptides having such a structure and have found several previously unknown peptide amides in procine upper small intestinal tissues. We report here the isolation and characterization of two of them, designated PHI and PYY. PHI is related to secretin, vasoactive intestinal polypeptide (VIP, glucagon and gastric inhibitory polypeptide (GIP); PYY is related to the pancreatic polypeptide and to neurotensin. Both peptides exhibit biological activities and appear to be present not only in the intestine but also in brain.
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PMID:Isolation of two novel candidate hormones using a chemical method for finding naturally occurring polypeptides. 689 50

Neuropeptide Y (NPY) is a 36 amino acid peptide known to inhibit glucose-stimulated insulin secretion. NPY has recently been shown to be synthetized within rat islets of Langerhans and to be secreted in a differentiated rat insulin-secreting cell line, and as to this date the localization of NPY in human endocrine pancreas has not been reported. As NPY shares high amino acid sequence homology with peptide YY (PYY) and pancreatic polypeptide (PP), the polyclonal antibodies raised against these peptides often cross-react with each other. To demonstrate the presence of NPY in the human endocrine pancreas, we used a highly specific monoclonal antibody raised against NPY and another against its C-flanking peptide (CPON). We studied three cases of hyperplasia of Langerhans islets and 11 cases of endocrine tumors of the pancreas. NPY and CPON were detected in all three cases of hyperplasia. For the 11 pancreatic tumors, five and nine of the tumors were positive for the antibodies NPY and CPON, respectively. The two negative tumors for CPON immunoreactivity were differentiated insulinomas, which showed no evidence of other hormonal secretion. In normal Langerhans islet, NPY and CPON immunoreactivities were colocalized in glucagon-producing cells (alpha-cells) and in a few insulin-secreting cell (beta-cells).(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Immunolocalization of neuropeptide Y in human pancreatic endocrine tumors. 747 36

Receptors for regulatory peptides (hormones or neurotransmitters) play a pivotal role in the ability of cells to taste the rich neuroendocrine environment of the gut. Recognition of low concentration of peptides with a high specificity and translation of the peptide-receptor interaction into a biological response through different signalling pathways (adenylyl cyclase-cAMP or phospholipase C-phosphatidylinositol) are crucial properties of receptors. While many new receptors have been identified and thereafter characterized functionally during the 1980s, molecular biology now emerges as the privileged way for the structural characterization and discovery of receptors. Different strategies of receptor cloning have been developed which may or may not require prior receptor purification. Among cloning strategies that do not require receptor purification, homology screening of cDNA libraries, expression of receptor cDNA or mRNA in Xenopus laevis oocytes or in COS cells, and the polymerase chain reaction method achieved great success, e.g. cloning of receptors for cholecystokinin, gastrin, glucagon-like peptide 1, gastrin-releasing peptide/bombesin, neuromedin K, neuropeptide Y, neurotensin, opioids, secretin, somatostatin, substance K, substance P and vasoactive intestinal peptide. All these receptors belong to the superfamily of G-protein-coupled receptors which consist of a single polypeptide chain (350-450 amino acids) with seven transmembrane segments, an N-terminal extracellular domain and a C-terminal cytoplasmic domain. In this chapter, we have detailed the properties of three receptors which play an important role in digestive tract physiology and illustrate various signal transduction pathways: pancreatic beta-cell galanin receptors which mediate inhibition of insulin release and intestinal epithelial receptors for vasoactive intestinal peptide and peptide YY, which mediate the stimulation and inhibition of water and electrolyte secretion, respectively.
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PMID:Receptors for gut regulatory peptides. 751 Sep 49

Neurotensin (NT), peptide YY (PYY), and several peptides derived from proglucagon are promptly released from endocrine cells of the distal part of the gut after oral ingestion of a meal, thus suggesting that release of these peptides is partly under neural and/or hormonal control. Our previous studies conducted with a model of isolated vascularly perfused rat colon showed that colonic L cells are highly responsive to several transmitters of the gut and to the hormonal peptide GIP. To test the possibility that hormones produced by the proximal small intestine or transmitters of the enteric nervous system may also modulate the secretory activity of the ileal L cells, various intestinal regulatory peptides and neurotransmitters were administered intraarterially for 30 min in the isolated vascularly perfused rat ileum preparation. The secretory activity of the ileal N cells was comparatively assessed. The release of NT, PYY, and glucagon-like peptide-1 (GLP-1) in the portal effluent was measured with specific RIAs. The muscarinic cholinergic agonist bethanechol at a concentration of 10(-4) M provoked a biphasic release of PYY, GLP-1, and NT, consisting of an early peak followed by a sustained response. Similarly, bombesin (10(-7) M) induced a marked biphasic release of PYY and GLP-1. In contrast, the NT response was essentially monophasic, characterized by an early peak secretion. Tetrodotoxin did not modify the bombesin-induced release of PYY, GLP-1, and NT. The beta-adrenergic agonist isoproterenol at a concentration of 10(-6) M induced a transient rise in portal PYY and GLP-1 concentrations, whereas the effect on NT release was clearly biphasic. Calcitonin gene-related peptide (5 x 10(-8) M) induced a dramatic rise in PYY, GLP-1, and NT immunoreactivities in the portal effluent (peaks at 600%, 500%, and 550% of the basal values, respectively, 4 mi n after the start of infusion). Intraarterial infusion of GIP over the concentration range (0.5-3 nM) evoked a significant increase in portal concentration of the three peptides only at the threshold concentration of 3 nM. Secretin (50 pM) or cholecystokinin (50 pM) did not affect the release of ileal hormones. In conclusion, ileal L and N cells respond to a variety of transmitters of the gut. The pattern of peptide release depends on the cell type studied. The two cosynthesized peptides, PYY and GLP-1, appear to be cosecreted in the conditions of the present study.
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PMID:Regulation of glucagon-like peptide-1-(7-36) amide, peptide YY, and neurotensin secretion by neurotransmitters and gut hormones in the isolated vascularly perfused rat ileum. 758 57


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