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 mechanisms controlling secretion of glucagon and other pancreatic hormones were studied in a patient affected with multihormone-secreting islet-cell tumor. Fasting glucagon levels (3,000 pg./ml.) rose to 10 ng./ml. following arginine stimulation. While oral glucose load and intravenous glucose infusion did not suppress glucagon secretion, insulin administration induced a prompt depression in glucagon levels. Glucagon, insulin, and gastrin levels were suppressed by somatostatin while calcium infusion caused a paradoxical increase. It is suggested that only some of the stimulation-inhibition mechanisms were conserved in this case of glucagon-secreting pancreatic tumor.
Diabetes 1976 May
PMID:Suppression and stimulation mechanisms controlling glucagon secretion in a case of islet-cell tumor producing glucagon, insulin, and gastrin. 0 26

A patient in whom Cushing syndrome had been diagnosed at the age of 23 was found 14 years later to have subclinical diabetes mellitus, subcutaneous calcified fat tissue necroses, and hypergastrinemia suggesting Zollinger-Ellison syndrome. Histopathologic investigation revealed pancreatic adenomatosis of the glucagon producing A2-cells with accompanying B-cell hyperplasia, and hyperplasia of the adrenal cortex. The origin of the increased serum gastrin concentration in this patient is not yet known. The significance of A2-cell proliferation in Zollinger-Ellison syndrome and and in multiple endocrine adenomatosis is discussed.
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PMID:[Glucagon producing adenomatosis of Islands of Langerhans with polyendocrine symptoms]. 1 53

Examination of glucose kinetics, pancreatic alpha and beta cell function, plasma lipids, urinary acidification and calcium excretion has been undertaken in a patient with hereditary fructose intolerance. This case was unusual as it was associated with insulin-requiring diabetes, type IV hyperlipemia, hypercalciuria and renal calculi. He also demonstrated the previously described fructose-induced defect of urine acidification. Glucagon and C-peptide assays showed that the pancreatic alpha cells were stimulated by fructose and that the beta cells did not respond to fructose. It is not known whether the latter was due to his diabetes or to the lack of a beta cell response to this sugar. Primed 14C-glucose infusions were used for the first time to study nonsteady state glucose kinetics in man. They showed that, 24 hours after the last insulin injection and under basal conditions, the glucose concentrations increased because glucose production exceeded glucose utilization. However, after the administration of sorbitol the plasma glucose concentration decreased because glucose production decreased. After the administration of sorbitol there was no change in the metabolic clearance of glucose. This reflects the lack of a peripheral insulin effect and is consistent with the lack of any measurable C-peptide. Glucose utilization also decreased, but this decrease was less than the decrease in glucose production. Because the metabolic clearance of glucose remained unchanged, it was concluded that the change in glucose utilization was solely due to the decrease in glucose concentration. The absence of C-peptide in the plasma indicated that changes in glucose turnover were not related to any changes in endogenous plasma insulin. Furthermore, the plasma glucagon concentration increased and, hence, changes in this hormone could not account for the decrease in glucose production. Therefore, it was concluded that the sorbitol-induced decline in glucose production was due to a direct effect on hepatic metabolism.
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PMID:Studies of glucose turnover and renal function in an unusual case of hereditary fructose intolerance. 1 54

The following evidence suggests that diabetes mellitus may not be the simple consequence of relative or absolute insulin deficiency by itself, but may require the presence of glucagon: (1) relative or absolute hyperglucogonaemia has been identified in every form of endogenous hyperglycaemia, including total pancreatectomy in dogs; (2) insulin lack in the absence of glucagon does not cause endogenous hyperglycaemia, but when endogenous or exogenous glucagon is present, it quickly appears, irrespective of insulin levels at the time. These facts are compatible with a bihormonal-abnormality hypothesis, which holds that the major consequence of absolute or relative insulin lack is glucose underutilisation and that absolute or relative glucagon excess is the principal factor in the over-production of glucose in diabetes.
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PMID:The essential role of glucagon in the pathogenesis of diabetes mellitus. 4 37

A 53 year old woman presented with diabetes mellitus, hyperglucagonemia (600 to 1,500 pg/ml), clinical hyperparathyroidism and an abdominal mass diagnosed on biopsy as an islet cell carcinoma. Glucagon content of the tumor was 0.78 mug/g wet weight. Hourly blood samples during a 24 hour period revealed a direct correlation between plasma glucose and glucagon. The oral administration of glucose paradoxically increased whereas the intravenous administration decreased plasma glucagon. Circulating glucagon levels were markedly increased with arginine and epinephrine infusion. Both short- and long-term administration of alpha adrenergic blockade depressed the glucagon response to epinephrine infusion. In contrast, long-term alpha adrenergic blockade increased glucagon secretion despite improved glucose tolerance during a second 24 hour study. Although the patient demonstrated overt clinical and chemical findings of hyperparathyroidism, parathyroid hormone (PTH) was not detected in her plasma. The pattern of tumor growth was consistent with an origin from pancreatic islets. We conclude that (1) the tumor was responsive to physiologic stimuli known to affect glucagon secretion; (2) elevations of plasma glucagon levels with oral and dietary glucose suggest regulation of secretion by intestinal factors; and (3) improvement of glucose tolerance with alpha adrenergic blockade may be related to increased insulin secretion.
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PMID:Uncontrolled diabetes mellitus and hyperglucagonemia associated with an islet cell carcinoma. 4 4

The proposition that glucagon plays an essential part in maintaining hyperglycaemia in diabetes has been investigated by the study of 5 totally pancreatectomised subjects and 5 age and sex matched insulin-dependent diabetic patients. True basal glucagon values were obtained by the use of a new affinity chromatography technique. The mean fasting plasma-glucose levels of the pancreatectomised subjects was 251 +/- 46 mg/dl. The mean fasting plasma-glucagon level was not significantly elevated above zero (1-3 +/- 0-6 pmol/l) and showed no change following arginine. In the 5 insulin-dependent diabetics the mean fasting plasma-glucagon level of 17-2 +/- 5-3 pmol/l rose to a maximum at 25 minutes of 103-6 +/- 27-5 pmol/l during infusion of arginine. These findings imply the absence of a significant number of normally functioning alpha cells in extrapancreatic sites in man and demonstrate that pronounced hyperglycaemia may occur in the absence of glucagon. Glucagon is probably not of primary importance in the hyperglycaemia of insulin-dependent diabetics.
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PMID:Pancreatectomised man: A model for diabetes without glucagon. 5 31

Diazoxide 5 mg/kg/day was administered to four normal subjects for five days and, together with insulin, to ten diabetic subjects for seven days. In every case there was a substantial increase in the insulin response to combined stimulation of the pancreatic beta cells with 1 mg of glucagon and 2 g of tolbutamide given intravenously. Similar increases were not seen in four diabetics who received placebo with insulin. It is likely that the observed improvements reflected increased insulin stores which resulted from diazoxide inhibition of insulin release. These findings suggest that poor insulin responses in diabetics may be due, at least in part, to chronic overstimulation of the beta cells. Pharmacological agents such as diazoxide, which inhibit glucose-induced insulin release, may have a place in preserving and restoring insulin secretion in diabetes.
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PMID:Improvement in insulin secretion in diabetes after diazoxide. 5 17

The isolated rat liver perfused for 12 hours at pH 7.10 with a suspension of bovine erythrocytes in Krebs-Ringer bicarbonate buffer containing 3 per cent bovine serum albumin has been used as a test system to study effects of glucagon and of dexamethasone in the presence and absence of insulin on net biosynthesis of rat serum albumin, fibrinogen, alpah1-acid glycoprotein, alpha2-(acute phase) globulin, and haptoglobin. Quantitative measurement of perfusate glucose, amino acid nitrogen, and urea affords a basis for determining net glucose and nitrogen balance in the perfusion system. Although the dose of dexamethasone (total 1.0 mug.) used was insufficient to induce synthesis of alpha2-acute phase globulin, net syntheses of albumin, fibrogen, alpha1-acid glycoprotein, and haptoglobin were increased. Glucagon given with dexamethasone depressed albumin and haptoglobin synthesis markedly, but not that of fibrinogen and alpha1-acid glycoprotein. Glucagon with dexamethasone markedly enhanced ureogenesis and glycogenolysis and elicited an exaggerated negative nitrogen balance. The unfavorable effects of glucagon on albumin and haptoglobin synthesis and on nitrogen balance were reversed by giving insulin simultaneously. It is emphasized that insulin is essential for positive nitrogen balance.
Diabetes 1976
PMID:Direct effects of glucagon on protein and amino acid metabolism in the isolated perfused rat liver. Interactions with insulin and dexamethasone in net synthesis of albumin and acute-phase proteins. 6 Nov 40

Autoantibodies reacting with discrete populations of cells in normal human pancreatic islets were found by immunofluorescence in 17 out of 1279 sera. A double immunofluorescence technique, with antisera to pancreatic glucagon, insulin, somatostatin, and human pancreatic polypeptide was used to show that 13 of the sera contained anitbodies reacting specifically with glucagon cells, while the other 4 reacted with somatostatin cells. These antibodies were directed against intracellular components and not against the hormones themselves. Both types of antibody occurred independently of the islet-cell antibodies which have been described in diabetes mellitus. These findings suggest selective damage to individual cell types in the pancreatic islets and raise the possibility of corresponding hormone deficiency syndromes.
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PMID:Separate autoantibodies to human pancreatic glucagon and somatostatin cells. 6 13

Infusion of somatostatin, an inhibitor of glucagon secretion, in insulin-dependent diabetics resulted in a 75-100% reduction in the blood-glucose rise after oral glucose administration, but did not improve intravenous glucose tolerance. Somatostatin reduced blood-xylose levels by 50-90% after ingestion of this pentose and delayed the peak increment in blood-xylose by 1-2 h. Similar effects on blood-xylose levels and a 30% reduction in splanchnic blood-flow were observed in normal subjects during infusion of somatostatin. Glucagon administration (3 ng per kg per min) or intraduodenal administration of xylose did not reverse somatostatin's effect on xylose tolerance. Somatostatin reduces postprandial hyperglycaemia in diabetes primarily by decreasing and/or delaying carbohydrate absorption rather than enhancing carbohydrate disposal. This effect may be mediated, in part, but a reduction in splanchnic blood-flow. These findings indicate that postprandial hyperglycaemia in diabetes is due primarily to insulin deficiency rather than glucagon excess.
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PMID:Influence of somatostatin on carbohydrate disposal and absorption in diabetes mellitus. 6 40


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