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 effect of zinc ions on carbohydrate metabolism and intracellular Zn2+ was studied in hepatocytes from fed rats. The addition of ZnCl2 to the medium led to an almost 3-fold increase in lactate production and an increase in net glucose production of about 50%. Half-maximal rates occurred at about 40 microM ZnCl2. These effects were not seen with Mn2+, Co2+, or Ni2+ up to 80 microM, whereas Cu2+ at 80 microM and Cd2+ or Pb2+ at 8 microM exhibited similar effects as 80 microM ZnCl2. Changes in intracellular Zn2+ were followed by single cell epifluorescence using zinquin as a specific probe. Intracellular free Zn2+ in isolated hepatocytes was 1.26 +/- 0.27 microM, and the addition of ZnCl2 led to a concentration-dependent increase in epifluorescence. CdCl2 or PbCl2 at 8 microM was as potent as ZnCl2 at 20-80 microM, whereas NiCl2 at 80 microM was without effect. ZnCl2 completely abolished the inhibition of glycolysis by glucagon (cAMP). Glucagon led to a pronounced drop in cytosolic Zn2+. Both glucagon and zinc stimulated glycogenolysis by increasing the phosphorylation of glycogen phosphorylase but acted oppositely on glycolysis. Zinc overcame the inactivation of pyruvate kinase by glucagon without changing the hormone-induced protein phosphorylation. The antagonistic action of zinc and cAMP on glycolysis together with the rapid and marked decrease in free zinc concentration induced by glucagon (cAMP) may indicate an as yet unknown role of zinc as an important mediator of regulation of carbohydrate metabolism.
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PMID:Intracellular zinc movement and its effect on the carbohydrate metabolism of isolated rat hepatocytes. 856 42

The model of rat primary hepatocytes incubated in DMEM/F12 (Ham) medium was used for studying the influence of the cAMP-effectors epinephrine (100 microM), norepinephrine (100 microM), glucagon (1 microM) and isoproterenol (1-1000 microM) as well as the synthetic cAMP-analogon dibutyryl-cAMP on the metabolism of metallothionein. Liver parenchymal cells isolated by a two-step collagenase perfusion were incubated with DMEM/F12 containing 5% (v/v) fetal calf serum (FCS) and 20 microM zinc in Petri dishes. Experiments were initiated after a 24 h equilibration period by adding the agonists for 18 h. MT in hepatocyte homogenates was quantified by the 109Cd-hemoglobin-binding assay. Cell viability was assessed by the activity of the cytosolic enzyme lactate dehydrogenase (LDH) liberated into the culture medium and by trypan blue exclusion. Isoproterenol and glucagon produced a significant increase of cytosolic MT about 50%. In contrast, incubation with epinephrine and norepinephrine did not lead to any significant effects in the amount of hepatic metallothionein. Simulating the influence of cAMP by dibutyryl-cAMP (500 microM) did not affect the content of hepatic metallothionein. To examine transcriptional and translational regulatory effects supplementation of cycloheximide (0.1-500 microM) and actinomycin D (0.1-100 microM) showed a total inhibition of the agonist induced amounts. Particularly in combination with isoproterenol low LDH activities reflected a high viability of hepatocytes. In conclusion, in primary hepatocyte cultures cAMP-mobilizing-agonists like isoproterenol and glucagon indicate an independent effect on the MT-metabolism. This is possibly due to the de novo synthesis of the protein because suppression by actinomycin D can be observed. However, cAMP-effectors do not seem to be involved in the induction of metallothionein because theophylline and dibutyryl-cAMP did not affect MT-metabolism by suppressing the phosphodiesterase or by stimulating the cAMP-cascade.
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PMID:Influence of cAMP-effector-agonists on the synthesis of metallothionein in rat primary hepatocytes. 858 45

Zinc deficiency is common in cirrhosis and has been involved in the altered nitrogen metabolism. In this study, we measured the effects of zinc supplementation on the dynamics of amino acid-derived urea synthesis in cirrhosis with mild or latent encephalopathy. The hepatic conversion of amino acids into urea was studied in eight patients with advanced cirrhosis under controlled conditions of substrate availability (continuous alanine infusion), before and after 3-month oral zinc sulfate supplementation (600 mg/d). Eight more patients, matched for hepatocellular failure and encephalopathy, served as controls. Plasma zinc levels were reduced in all patients and returned to normal after oral zinc. The alanine-stimulated urea nitrogen synthesis rate in relation to alpha-amino-N concentration--the functional hepatic nitrogen clearance--increased by 25% after zinc supplementation, i.e., more urea was produced at any alpha-amino-N concentration. Basal and alanine-induced glucagon decreased by 50%, and the ammonia response to alanine decreased by 30%. Psychometric tests improved, as did routine and dynamic liver function tests and the Child-Pugh score. Also, the plasma concentration of lipid peroxides was reduced by zinc. No significant changes were observed in the control group. Our data indicate that long-term oral zinc speeds up the kinetics of urea formation from amino acids and ammonia. Changes in the hormonal drive and/or the antioxidant activity of zinc might be involved in the general improvement in liver function, whereas the beneficial effects on encephalopathy might stem from decreased ammonia.
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PMID:Zinc supplementation and amino acid-nitrogen metabolism in patients with advanced cirrhosis. 862 Nov 38

Necrolytic migratory erythema (NME) is an uncommon condition classically associated with high plasma levels of circulating glucagon and a glucagonoma. We report a patient with cirrhosis who showed clinical and histological features of NME. Investigation revealed normal glucagon levels without evidence of glucagonoma. Serum zinc levels were below the normal range and zinc supplementation resulted in rapid and complete resolution of the eruption.
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PMID:Necrolytic migratory erythema and zinc deficiency. 947 Sep 39

We present an infant with severe familial hyperinsulinism in whom glucose production rate, lipolysis, and gluconeogenesis from glycerol were measured by use of glucose and glycerol labelled with stable isotopes. Administration of a single dose of glucagon (0.1 mg/kg) caused an increase in glucose production rate by near 140% from 4.2 to 10.1 mg.kg-1.min-1. The rate of appearance of glycerol, reflecting the rate of lipolysis, decreased from 15.1 to 12.6 micromol. kg-1.min-1. The amount of glycerol converted to glucose by gluconeogenesis was 9.1 micromol.kg-1.min-1 before and 10.5 micromol. kg-1.min-1 after glucagon administration. We conclude that the marked rise in glucose production rate was mainly the result of increased glycogenolysis. Following the trial, the child was started on long-acting (zinc-protamine) glucagon which made it possible to discontinue intravenous treatment with glucose.
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PMID:Effect of glucagon on glucose production, lipolysis, and gluconeogenesis in familial hyperinsulinism. 970 3

Necrolytic migratory erythema (NME) is generally associated with glucagonoma. It waxes and wanes by successive relapses and remissions. The clinical and microscopical diagnosis is complex. In addition to glucagonoma treatments, the administration of corticoids, aminoacids, zinc or essential fatty acids can be helpful. There exist several etiological hypotheses for NME. These are based on modifications of pancreatic enzyme activities and on variations of aminoacids, fatty acids, zinc or glucagon concentrations.
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PMID:[Necrolytic migratory erythema]. 992 78

Acute or chronic zinc administration may cause hyperglycemia in experimental animals. These findings are attributed to permissive actions of glucocorticoids and glucagon upon hepatic gluconeogenesis and glycogenolysis. The effect of Zn(+)+ on plasma glucose, C-peptide, glucagon, and cortisol was investigated in healthy and insulin-dependent diabetes mellitus (IDDM) patients. Ten normal individuals (5 of each sex, aged 24.10 +/- 1.96) and 10 IDDM (5 of each sex, aged 25.20 +/- 8.10) were tested at 7:00 AM after 12-h fast. Twenty-five mg of Zn(+)+ were administered intravenously during 1 min, and blood samples were collected from the contralateral arm at 0, 3, 30, 60, 90 and 120 min after Zn(+)+ injection. The plasma levels of glucose, C-peptide, and glucagon remained constant throughout the experimental period in both groups studied. Plasma cortisol levels decreased significantly, which is consistent with our previous findings. These results suggest that, in contrast to experimental animals, acute Zn(+)+ administration, despite decreasing cortisol levels, does not change carbohydrate metabolism in human beings.
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PMID:Lack of acute zinc effects in glucose metabolism in healthy and insulin-dependent diabetes mellitus patients. 1040 85

It is clear that cutaneous lesions of metabolic epidermal necrosis in the dog can occur either with a demonstrable glucagon-secreting tumor or with hepatic disease without any detectable glucagonoma. Additional clinical case reports of the disease in cats are needed to better characterize the disease in this species. The lesions of NME-MEN may not represent a specific physiological mechanism of cutaneous disease but instead a pathophysiological process that can be triggered by several systemic metabolic abnormalities. The fact that NME is observed in association with a variety of conditions supports the theory that an overall metabolic derangement results in the rash. The prognosis for canine MEN is poor; however, some affected dogs have been maintained for many months with dietary management. High-quality protein diets such as Hill's Prescription Diet a/d (Hill's Pet Products) or other "recovery" diets may be helpful. Zinc and essential fatty acid supplementation may help some patients. Dietary supplementation with cooked egg yolks may be helpful. It is prudent to avoid corticosteroids in these cases, as development of diabetes mellitus worsens the prognosis. Histopathological examination of the pancreas coupled with determination of plasma glucagon may help define the characteristics of GS versus HS in dogs. It is possible that some dogs diagnosed with MEN-HS may have an undetected pancreatic tumor. Although the hepatic ultrasound findings in dogs with MEN-HS are becoming well characterized, it is possible for dogs with pancreatic neuroendocrine tumors to also have abnormal hepatic ultrasonography. As the presence of MEN and hepatic disease does not necessarily rule out the presence of a pancreatic tumor, prospective studies correlating plasma glucagon levels with pancreatic histopathology in cases of MEN-GS versus MEN-HS seem warranted.
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PMID:Metabolic epidermal necrosis-hepatocutaneous syndrome. 1056 4

Several lines of evidence demonstrate that general nutritional status, specific nutrients (eg, zinc, glutamine), and certain trophic growth factors (eg, growth hormone, insulin-like growth factor I, keratinocyte growth factor, and glucagon-like peptide-2) have important interactions relevant for intestinal growth and function. Adequate nutritional status is critical for endogenous growth factor synthesis in the gut and other tissues and is an important mediator of organ responsiveness to exogenous growth factor administration. Both endogenously synthesized and exogenously administered growth factors upregulate nutrient uptake and utilization by gut mucosa, skeletal muscle, and other organs. Emerging data from both animal and human studies indicate that combinations of selected growth factors and specific nutrients may improve the growth, adaptation, and repair of the intestinal mucosa. Additional studies to determine basic mechanisms of nutrient-growth factor interactions and the safety and efficacy of treatment with combinations of specific nutrients and recombinant growth factors are needed. Results of these investigations should define new methods for support of the intestinal tract during short bowel syndrome (SBS), catabolic illness, and malnutrition.
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PMID:Interactions between nutrients and peptide growth factors in intestinal growth, repair, and function. 1057 52

Activation of glucagon-like peptide (GLP)-1 receptor signaling promotes glucose lowering via multiple mechanisms, including regulation of food intake, glucose-dependent insulin secretion, and stimulation of beta-cell mass. As GLP-1 exhibits a short t(12) in vivo, the biological consequences of prolonged GLP-1 receptor signaling remains unclear. To address this question, we have now generated metallothionein promoter-preproexendin (MT-Ex) transgenic mice. MT-Ex mice process preproexendin correctly, as is made evident by detection of circulating plasma exendin-4 immunoreactivity using high pressure liquid chromatography and an exendin-4-specific radioimmunoassay. Despite elevated levels of exendin-4, fasting plasma glucose and glucose clearance following oral and intraperitoneal glucose tolerance tests are normal in MT-Ex mice. Induction of transgene expression significantly reduced glycemic excursion during both oral and intraperitoneal glucose tolerance tests (p < 0.05) and increased levels of glucose-stimulated insulin following oral glucose administration (p < 0.05). Despite evidence that exendin-4 may induce beta-cell proliferation, beta-cell mass and islet histology were normal in MT-Ex mice. MT-Ex mice exhibited no differences in basal food intake or body weight; however, induction of exendin-4 expression was associated with reduced short term food ingestion (p < 0.05). In contrast, short term water intake was significantly reduced in the absence of zinc in fluid-restricted MT-Ex mice (p < 0.05). These findings illustrate that sustained elevation of circulating exendin-4 is not invariably associated with changes in glucose homeostasis, increased beta-cell mass, or reduction in food intake in mice in vivo.
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PMID:Sustained expression of exendin-4 does not perturb glucose homeostasis, beta-cell mass, or food intake in metallothionein-preproexendin transgenic mice. 1095 81


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