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 endocrine function of the pancreas consists of the promotion of storage of nutritive substances after meals through the liberation of insulin and to guarantee the mobilization of this food energy through the secretion of glucagon during fasting. Increased hormone production may result from tumors of the islet cells (insulin: insulinoma; glucagon: glucagonoma; gastrin: Zollinger-Ellison syndrome). An absolute or relative insulin deficiency is a characteristic of diabetes mellitus, in which a relative hyperglucagonemia is also of possible pathophysiological significance. This increased secretion of glucagon can be suppressed by somatostatin. While the clinical application of somatostatin in diabetes mellitus seems problematic at present, the use of a glucose-controlled system of insulin infusion ("artificial pancreas") makes possible a metabolic state approaching the healthy condition.
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PMID:[The endocrine pancreas. From the isolated islet to the "artificial pancreas" (author's transl)]. 81 14

A 76-year-old man presented with hypoglycemic coma associated with metastatic liver disease. Serum immunoreactive insulin excluded insulinoma as a cause of hypoglycemia. Negative glucose responses to glucagon and epinephrine testing indicated failure of compensatory glycogenolysis. The patient's increased glucose requirements of 500 g per 24 hr were reduced to normal only after shrinkage of the liver tumor bulk was accomplished with chemotherapy. Hepatic hypoglycemia is discussed and the literature is reviewed.
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PMID:Hypoglycemia secondary to metastases to the liver. A case report and review of the literature. 83 May 86

Glucagon (1 mg) and glucose (60 ml of 50% solution) were infused over 60 min to three normal and one obese subjects and two insulinoma patients. Plasma C-peptide immunoreactivity (CPR) and immunoreactive insulin (IRI) increased during the infusion. Half time of CPR after cessation of the infusion was 20.1 +/- 4.0 min, and that of IRI 9.8 +/- 1.3 min, respectively. This difference partly explains the higher molar concentration in plasma of CPR than IRI.
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PMID:Disappearance rate of endogenous human C-peptide from blood. 97 39

Nitric oxide has recently been implicated as the effector molecule that mediates IL-1 beta-induced inhibition of glucose-stimulated insulin secretion and beta-cell specific destruction. The pancreatic islet represents a heterogeneous cell population containing both endocrine cells (beta-[insulin], alpha-]glucagon], gamma[somatostatin], and PP-[polypeptide] secreting cells) and non-endocrine cells (fibroblast, macrophage, endothelial, and dendritic cells). The purpose of this investigation was to determine if the beta-cell, which is selectively destroyed during insulin-dependent diabetes mellitus, is both a source of IL-1 beta-induced nitric oxide production and also a site of action of this free radical. Pretreatment of beta-cells, purified by FACS with IL-1 beta results in a 40% inhibition of glucose-stimulated insulin secretion that is prevented by the nitric oxide synthase inhibitor, NG-monomethyl-L-arginine (NMMA). IL-1 beta induces the formation of nitric oxide by purified beta-cells as evidenced by the accumulation of cGMP, which is blocked by NMMA. IL-1 beta also induces the accumulation of cGMP by the insulinoma cell line Rin-m5F, and both NMMA as well as the protein synthesis inhibitor cycloheximide prevent this cGMP accumulation. Iron-sulfur proteins appear to be intracellular targets of nitric oxide. IL-1 beta induces the formation of an iron-dinitrosyl complex by Rin-m5F cells indicating that nitric oxide mediates the destruction of iron-sulfur clusters of iron containing enzymes. This is further demonstrated by IL-1 beta-induced inhibition of glucose oxidation by purified beta-cells, mitochondrial aconitase activity of dispersed islet cells, and mitochondrial aconitase activity of Rin-m5F cells, all of which are prevented by NMMA. IL-1 beta does not appear to affect FACS-purified alpha-cell metabolic activity or intracellular cGMP levels, suggesting that IL-1 beta does not exert any effect on alpha-cells. These results demonstrate that the islet beta-cell is a source of IL-1 beta-induced nitric oxide production, and that beta-cell mitochondrial iron-sulfur containing enzymes are one site of action of nitric oxide.
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PMID:Interleukin 1 beta induces the formation of nitric oxide by beta-cells purified from rodent islets of Langerhans. Evidence for the beta-cell as a source and site of action of nitric oxide. 133 75

A 42-year-old woman with a family history of multiple endocrine neoplasia type 1 (MEN 1) presented with symptomatic hypoglycaemia and peptic ulceration. Investigation revealed an insulinoma, hyperparathyroidism, hypercalcitoninaemia with a positive pentagastrin stimulation test, acromegaly due to a GRF-oma, hyperprolactinaemia and normal serum gastrin levels. Five pancreatic tumours were removed at laparotomy and immunostaining was positive for insulin, calcitonin, somatostatin and glucagon. Post-operatively she developed elevated serum gastrin levels and gross peptic ulceration, despite H2-blockers, and died of gastro-intestinal haemorrhage suggesting that removal of the somatostatinoma may have allowed increased gastrin secretion from a gastrinoma. This case emphasizes the importance of measuring a wide variety of tumour marker peptides in MEN 1 and suggests that caution is required in interpretation of the pentagastrin stimulation test in such cases. Patients with MEN 1 and known peptic ulceration may require perioperative omeprazole treatment even if serum gastrin levels are normal.
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PMID:A case of multiple endocrine neoplasia: hyperparathyroidism, insulinoma, GRF-oma, hypercalcitoninaemia and intractable peptic ulceration. 135 65

Oxyntomodulin (OXM), a glucagon-containing peptide extended at its C-terminal end by an octapeptide, is a potent inhibitor of gastric acid secretion in rat and man. OXM appears to act on gastric mucosa at least partially through a stimulation of gastric somatostatin release. We have investigated the effects of OXM on a somatostatin-secreting cell line (RIN T3) derived from a radiation-induced rat insulinoma and characterized specific binding sites for this peptide. OXM increased somatostatin release with an ED50 of 2.3 nM. OXM also stimulated the cAMP accumulation in intact RIN T3 cells and adenylate cyclase activity in RIN T3 cell membranes with ED50 values of 0.5 and 11 nM, respectively. On these parameters, glucagon was 10-30 times less potent than OXM. Forskolin, isobutylmethylxanthine, and 8-bromo-cAMP mimicked the effect of OXM on somatostatin release. Specific binding for mono-[125I]OXM was dependent upon time and membrane concentration. Binding of mono-[125I]OXM was inhibited by OXM and glucagon in a concentration-dependent manner, with dissociation constants (Kd) of 4.5 and 43 nM, respectively. The nonhydrolyzable analogs of GTP (guanosine 5',3-O-(thio)triphosphate and guanosine 5' (beta,gamma-imino)triphosphate decreased the binding of mono-[125I]OXM to its binding sites. Covalent cross-linking of mono-[125I]OXM or mono-[125I]glucagon to RIN T3 cell membranes followed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis demonstrated a single radiolabeled band at 63,000 mol wt, which differed from that observed after cross-linking with liver plasma membranes (55,000 mol wt). These results demonstrate the presence of specific high affinity binding sites for OXM in a somatostatin-secreting cell line (RIN T3) and their coupling to adenylate cyclase via guanine nucleotide-binding proteins.
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PMID:Characterization of binding sites for oxyntomodulin on a somatostatin-secreting cell line (RIN T3). 137 46

The endocrine cells of the pancreas develop from the endoderm and yet display several characteristics of a neuronal phenotype. During embryonic life, ductal epithelial cells give rise to first the glugagon-producing cells (alpha-cells) and then cells that express insulin (beta-cells), somatostatin (delta-cells), and pancreatic polypeptide (PP-cells) in a sequential order. The endocrine cells are believed to arise from a stem cell with neuronal traits. The developmental lineage from a common neuron-like progenitor is evidenced by: transient coexpression of more than one cell type-specific hormone in immature cells, expression of neuronal markers during islet cell development, and the pluripotentiality of clones of insulinoma cells to develop into cells expressing other islet cell hormones. The four mature endocrine cell types assume a particular organization within the islets of Langerhans in a process where cell adhesion molecules are involved. In this study we have analyzed the expression of neural cell adhesion molecule (NCAM) and cadherin molecules in neonatal, young, and adult rat islet cells as well as in glucagonomas and insulinomas derived from a pluripotent rat islet cell tumor. Whereas primary islet cells at all ages express unsialylated NCAM and E-cadherin, as do insulinomas, the glucagonomas express the polysialylated NCAM, which is characteristic for developing neurons. The glucagonomas also lose E-cadherin expression and instead express a cadherin which is similar to N-cadherin in brain. Insulinoma cells express E-cadherin but differ from primary islet cells by expressing a second cadherin molecule, which is similar to N-cadherin. The expression of NCAM and cadherin isoforms in the glucagonoma suggest that this transformed alpha-cell type has converted to an immature phenotype with strong neuronal traits, reflecting the early palce of glucagon-producing cells in the islet cell lineage. In contrast, insulinoma cells are more islet-like in their phenotype and show less neuronal traits.
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PMID:Differential expression of neural cell adhesion molecule and cadherins in pancreatic islets, glucagonomas, and insulinomas. 140 10

Cystic glucagonoma in contact with insulinoma was found in the pancreas of a 28-year-old female patient with characteristic hypoglycemic syndrome. Among six tumors in total detected in the tail of the resected pancreas, the largest solid tumor (2.5 cm in diameter) consisted mostly of insulin-containing cells with conspicuous amyloid deposition. Contiguous to this tumor, the second largest nodule, measuring 1.8 cm in diameter, showed cystic changes and consisted of glucagon-containing cells. High concentration of immunoreactive glucagon was demonstrated in the cystic fluid. In addition to the cystic changes of endocrine pancreatic tumors, simultaneous occurrence of glucagonoma in contact with insulinoma appears to be extremely rare and repeated episodes of hypoglycemia may contribute to its pathogenesis.
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PMID:Cystic pancreatic glucagonoma in contact with insulinoma found in a hypoglycemic patient. 143 39

We report the results of transcatheter intraarterial perfusion of liver with the emulsion of iodized oil and cytostatics performed as palliative treatment in three patients with hepatic metastases of pancreatic endocrine tumors. Two patients had insulinoma and one patient had glucagonoma. They were also treated by medical therapy from the time the diagnosis was made. Intraarterial perfusion of the liver was achieved by Lipiodol emulsified with streptozotocin and 5-fluorouracil. Regarding these three patients therapeutic responses were different in duration of hormone secretion decrease. Relief of hypoglycemic attacks and a significant decrease of plasma immunoreactive insulin concentration within 12 months without any additional therapy was observed in the patient with insulinoma (case no. 2). This patient had slightly increased immunoreactive glucagon concentration from the time of diagnosis. A decrease of immunoreactive insulin levels in other patient with insulinoma and an increase in plasma glucose to the euglycemic range during two months allowed a reduction of doses of somatostatin analogue and diazoxide. Due to rapid progression of the disease, intraarterial perfusion of liver was repeated three months later with the same results. Remission of symptoms was partial in the case of glucagonoma. Immunoreactive glucagon levels were not changed and there was no significant benefit of the treatment. Intraarterial perfusion of liver with iodized oil and cytostatics could be an effective, safe and repeatable method of palliating symptoms of malignant pancreatic tumors, especially in inoperable but nonterminal cases. It could allow reduction of additional medical therapy, but success of the treatment is not predictable.
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PMID:Improvement of metastatic endocrine tumors of the pancreas by hepatic artery chemoembolization. 144 92

Side effects of octreotide may be local, biochemical, gastroenterological, or endocrinological. Local pain at the injection site occurs frequently, but rarely lasts more than 15 minutes and often resolves with continued therapy and may be improved if the vial is warmed prior to injection. No long-term hematological or biochemical abnormalities have been described. Despite initial diarrhea in some patients, no change in circulating fat-soluble vitamins has been consistently reported. Antibodies to octreotide have been described, but are rare. Abdominal pain or diarrhea can occur at the beginning of therapy. These symptoms rarely persist and are minimal if the injections are timed between meals, but this may increase the incidence of gallstones. Gallstones occur with increased frequency. Gastritis has been described as being an invariable consequence of long-term treatment with octreotide. We have found the incidence to be increased in patients on octreotide, but this is not invariable. Hypoglycemia may be exacerbated in some patients with insulinoma because of glucagon suppression. Small numbers of patients on octreotide for acromegaly have developed hypoglycemic. Conversely, carbohydrate tolerance may temporarily worsen because of insulin suppression and rarely oral hypoglycemia drug therapy may become necessary. Most frequently, carbohydrate tolerance does not deteriorate. In some patients with acromegaly, pituitary tumor size may continue to increase despite continued therapy. Last, there is the theoretical risk of addiction to a compound which may act through opiate receptors and considerably alleviates headache in some patients with pituitary tumor. Overall, despite the multiplicity of theoretical side effects, the majority of patients tolerate octreotide well, with no serious untoward effects.
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PMID:Proceedings of the discussion, "Tolerability and safety of Sandostatin". 151 39


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