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)

We have perfused isolated rat livers with hypocalcemic (4.4 mg 100 ml) Krebs-Ringer bicarbonate albumin buffer. After 15 min of perfusion, a substance appeared in the perfusate which decreased rat renal adenylate cyclase activation by parathyroid hormone (PTH). The material in the perfusate was purified greater than 50,000-fold by Bio-Gel P-10 chromatography. The purified antagonist decreased the activation of rat renal cortical adenylate cyclase by PTH, glucagon, and epinephrine 75 to 100%. Concentration response curves for each of the hormones indicated a noncompetitive interaction of the inhibitor with the hormone. The inhibition was not species-specific, as the activation of the parathyroid hormone-responsive adenylate cyclase in cat renal cortex was also abolished by the inhibitor from the perfused rat liver. The inhibitor is a peptide, Mr equal to similar to 1000, which is heat-stable, acid-stable, alkai-labile, and is destroyed by trypsin, leucine aminopeptidase, and elastase. It is not destroyed by phosphodiesterase, 5'-nucleotidase, alkaline phosphatase, neuraminidase, RNase, or phospholipase A. The inhibitor is not produced by isolated rat livers perfused with normocalcemic perfusion media. It is unclear whether the peptide is synthesized by the liver or whether it is a breakdown product of a larger peptide or protein in the liver. This is the first reported peptide inhibitor of adenylate cyclase.
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PMID:Isolation of a unique peptide inhibitor of hormone-responsive adenylate cyclase. 16 24

The terminal glycoproteins of fetal, cultivated (7-12 days), and adult nondiabetic and diabetic pancreatic tissues (Balb c, C3h mice) were investigated by lectin histology (peanut-, phytohemagglutinin, wheat germ agglutinin, Ulex europeus I, concanavalin A and Ricinus communis agglutinin, PaP method +/- neuraminidase). Anti-insulin and -glucagon were used to identify islet cells. S-100 antibody showed dendritic reticulum cells, anti-IAK proved MHC II antigens (C3h). Cultured tissue was partly incubated with anti-IAK and complement for lysis of MHC II antigens. On the 19th gestational day fetal pancreatic tissue did not bind peanut agglutinin, Phytohemagglutinin, or wheat germ agglutinin, whereas concanavalin A and Ricinus communis were weakly bound. Terminal fucose residues were not expressed by C3h fetal islet cells in contrast to Balb c. Following neuraminidase digestion peanut agglutinin and phytohemagglutinin were strongly bound, indicating sialic acid-substituted terminal glycoproteins. Cultivated tissue (Day 7) bound all investigated lectins (except Ulex europeus I in C3h mice), indicating maturation of islet cells. In spite of the peak of insulin concentration in the medium we observed a faint binding of anti-insulin and investigated lectins following 12 days of cultivation. This indicates a disorder of terminal glycoprotein synthesis at this point. There was no difference in lectin binding patterns of adult nondiabetic islet cells compared to the cultivated tissue (7 days), but no Ulex europaeus I binding of the adult Balb c mice was observed. S-100 binding decreased during the cultivation period as dendritic reticulum cells became destroyed by cultivation.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Lectin histochemical investigations of fetal cultivated pancreatic tissue. 140

The glycoproteinic nature of the insulin receptor was indicated using two different approaches: 1. [125I] insulin binding to soluble receptors from mouse liver was inhibited by digestion with beta-galactosidase or pretreatment with Ricinus communis I or concanavalin A. An other enzyme (neuraminidase) and lectins (wheat germ agglutinin, Dolichos biflorus) did not affect the binding reaction. These data confirmed that insulin directly interacts with the galactoglycoproteins of liver membranes. 2. The galactose oxidase-sodium boro[3H] hydride technique, previously used for labeling accessible membrane galactoglycoproteins, was again utilized to discern the components that interact with insulin. When liver membranes were equilibrated with 10-7 M insulin prior to labeling, the SDS gel radioactive profiles were specifically modified with two galactoglycoprotein of apparent molecular sizes 195 000 and 145 000, compatible with their participation in the insulin binding interaction. Membrane pretreatment with beta-galactosidase or Sophora japonica lectin reduced the labeling in most peaks, thus supporting the argument for labeling sensitivity. Preincubation of membranes with 10-7 M proinsulin slightly hindered labeling, while pretreatment with 10-7 M glucagon was ineffective, suggesting a specificity of the insulin effect. These data indicate that glycoprotein nature of the insulin receptor for two reasons: alteration of insulin binding after modification of the galactoglycoproteins, and alteration of galactoglycoprotein labeling after insulin binding. Two galactoglycoproteins, with apparent molecular weights 145 000 and 195 000, respectively, were identified and they are suggested to have insulin binding properties.
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PMID:Identification of liver cell membrane galactoglycoproteins involved in the process of insulin binding. 703 Mar 99

The histochemical binding sites of peanut agglutinin (PNA) to normal foetal and neonatal pancreas and to pancreatic tissue from two cases with persistent neonatal hyperinsulinaemic hypoglycaemia were studied. For the demonstration of masked PNA binding sites, neuraminidase digestion was utilized. In addition, pancreatic endocrine cells were identified by immunocytochemistry for insulin, glucagon and somatostatin. Likewise, double immunohistochemical staining for simultaneous visualization of PNA binding sites and insulin reactive cells was employed. In pancreatic exocrine tissue, PNA binding occurred in all cases without neuraminidase treatment. Insular endocrine cells expressed PNA binding both in normal neonatal cases and in those with hyperinsulinaemic hypoglycaemia, but only after neuraminidase treatment. In foetal pancreas, no PNA binding was found on endocrine cells even after neuraminidase treatment, and it was also absent from B-cells in areas of the normal neonatal pancreas that showed the characteristic picture of nesidioblastosis. The possible mechanisms involved in determining the different pattern of PNA reactivity in foetal and neonatal endocrine pancreas are considered.
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PMID:Peanut lectin binding sites in human foetal and neonatal pancreas. 751 May 39

125I-Glucagon was directly cross-linked to its receptor sites on the MDCK plasma membranes using a UV irradiation procedure. Analysis of the affinity labeled membranes by SDS-PAGE and autoradiography, demonstrated the presence of a single band at 74 kDa. The incorporation of radiolabeled glucagon into this band was abolished by the presence of excess unlabeled hormones, thus indicating a specificity of labeling. Also this band was observed in affinity labeled dog kidney plasma membranes. The size of the MDCK and the dog kidney glucagon receptors were consistently larger than that of the dog liver receptor as judged by electrophoretic mobility. Treatments with neuraminidase, endoglycosidase F, or N-glycanase failed to convert the renal form into the hepatic form of the receptor. Proteolytic mapping of the MDCK and the dog liver glucagon receptors revealed that major domains of both proteins are remarkably similar, yet transient variations in the size of the fragments could be detected after short duration digestions. Overall the data presents evidence that the dog renal receptor represents a structurally unique isoform of the glucagon receptor.
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PMID:Canine kidney glucagon receptor: evidence for a structurally-different, tissue-specific variant of the glucagon receptor. 867 61