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)

Plasma glucose and glucagon concentrations were measured in edible dormice during the bout of hibernation, arousal and active periods. During lethargy, plasma glucose and glucagon were low, compared to active values and did not fluctuate throughout the phase. During rewarming, plasma glucose regularly increased from 17 degrees to 37 degrees C while plasma glucagon rose after the 17 degrees C stage and reached the higher values at 26 degrees C, then slightly decreased at 37 degrees C. During arousal, plasma levels of free amino acids progressively increased. The effect of temperature and secretagogue (glucose and arginine) on glucagon secretion was studied using perfused pancreas from hibernating edible dormouse. In vitro rewarming of pancreas induced an increase in glucagon secretion. Glucagon secretion was regulated by glucose (inhibitory effect) and by arginine (stimulating effect) up to 25 degrees C. The effect of temperature and glucagon on oxygen uptake of hibernating edible dormouse brown fat was studied using an in vitro technique. Rewarming strongly increased oxygen consumption from 10 to 37 degrees C. Glucagon enhanced oxygen consumption up to 20 degrees C.
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PMID:Glucagon secretion in the hibernating edible dormouse (Glis glis). 286 68

Cysteamine (CSH; beta-mercaptoethylamine) is known to deplete pancreatic somatostatin without affecting the insulin or glucagon content. It may therefore be useful for studies of intra-islet regulation of hormone release. In the present study injection of CSH (60 mg/kg body weight) to mice decreased the somatostatin content of their isolated pancreatic islets to 50% in 1 h and 30% in 4 h as compared to islets of non-injected controls. Exposure of isolated mouse islets to CSH (100 micrograms/ml) for either 0.5 h followed by incubation in control medium for 3.5 h, or continuously for 4 h, decreased the somatostatin content to about 40% of the controls. There was no change in the islet content of insulin or glucagon. Islets pretreated with CSH (100 micrograms/ml) for 1 h in vitro showed a decreased glucose stimulation of both oxygen consumption and glucose oxidation. Measurements of insulin release after a similar preincubation of the islets indicated an increased basal release and an attenuated glucose stimulation. It is concluded that CSH rapidly decreases islet somatostatin both in vivo and in vitro. This depletion may lead to a loss of tonic inhibition by islet somatostatin on basal insulin release. It is, however, more plausible that the increased basal insulin release reflected a direct effect of CSH on the islet beta-cells.
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PMID:Rapid depletion of somatostatin in isolated mouse pancreatic islets after treatment with cysteamine. 286 62

This experiment was performed to determine if plasma glucose homeostasis is maintained in normal human volunteers during light exercise (40% maximal oxygen consumption [VO2 max]) when changes in insulin and glucagon are prevented. Hormonal control was achieved by the infusion of somatostatin, insulin, and glucagon. Glucose kinetics and oxidation rates were determined with stable isotopic tracers of glucose, and by indirect calorimetry. Two different rates of replacement of insulin and glucagon were used; in one group, insulin was clamped at 19.8 +/- 2.6 microU/ml (high-insulin group), and in the other group insulin was clamped at 9.2 +/- 1.3 microU/ml (low-insulin group). Glucagon was maintained at 261 +/- 16.2 and 124 +/- 6.4 pg/ml, respectively, in the high-insulin and low-insulin groups. Without hormonal control, plasma glucose homeostasis was maintained during exercise because the increase in glucose uptake was balanced by a corresponding increase in glucose production. When changes in insulin and glucagon were prevented, plasma glucose concentration fell, particularly in the high-insulin group. Glucose uptake increased to a greater extent than when hormones were not controlled, and glucose production did not increase sufficiently to compensate. The increase in glucose uptake in the hormonal control groups was associated with an increased rate of glucose oxidation. When euglycemia was maintained by glucose infusion in the hormonal control subjects, the modest increase in glucose production that otherwise occurred was prevented. It is concluded that during light exercise there must be a reduction in insulin concentration and/or an increase in glucagon concentration if plasma glucose homeostasis is to be maintained. If such changes do not occur, hypoglycemia, and hence exhaustion, may occur.
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PMID:Role of changes in insulin and glucagon in glucose homeostasis in exercise. 286 53

We studied the influence of hyperglycemia on glucose homeostasis in man by determining the effect of graded hyperglycemia on peripheral glucose uptake and systemic metabolism in the presence of basal and increased serum insulin concentrations in 10 normal men. This was achieved by the simultaneous application of forearm and clamp techniques (euglycemic and hyperglycemic) during the combined iv infusion of somatostatin, glucagon, and insulin. While mean (+/- SE) basal serum insulin levels (14 +/- 2 microU/ml) were maintained, the elevation of fasting arterial glucose concentrations (90 +/- 1 mg/dl) to 146 +/- 1 and 202 +/- 1 mg/dl (each for 120 min) increased forearm glucose uptake (FGU) only modestly from 0.06 +/- 0.01 to 0.15 +/- 0.02 and then to 0.24 +/- 0.03 mg/100 ml forearm X min, respectively. During physiological hyperinsulinemia (47 +/- 3 microU/ml), the influence of similar graded hyperglycemia on FGU was considerably enhanced. At plasma glucose concentrations of 90 +/- 1, 139 +/- 1, and 206 +/- 1 mg/dl, FGU rose to 0.33 +/- 0.05, 0.59 +/- 0.07, and 0.83 +/- 0.12 mg/100 ml forearm X min, respectively. The glucose infusion rate required to maintain the glucose clamp with basal insulin levels was 1.08 +/- 0.20 and 2.67 +/- 0.39 mg/kg X min at glucose concentrations of 146 +/- 1 and 202 +/- 1 mg/dl, respectively. During physiological hyperinsulinemia, however, the glucose infusion rate required was 4.15 +/- 0.39, 9.45 +/- 1.05, and 12.70 +/- 0.81 mg/kg X min at glucose levels of 90 +/- 1, 139 +/- 1, and 206 +/- 1 mg/dl, respectively. Lactate concentrations rose significantly during hyperglycemia, but the rise in the presence of increased insulin concentrations (from 0.72 +/- 0.06 to 1.31 +/- 0.11 mmol/liter; P less than 0.001) considerably exceeded the increment (from 0.74 +/- 0.05 to 0.92 +/- 0.03 mmol/liter) with basal insulin levels. While both FFA and glycerol concentrations were immediately reduced by euglycemic hyperinsulinemia, the fall in FFA during hyperglycemia in the presence of basal insulin levels preceded the decrease in glycerol concentrations by 45 min. Forearm oxygen consumption did not change throughout the study.(ABSTRACT TRUNCATED AT 400 WORDS)
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PMID:The influence of graded hyperglycemia with and without physiological hyperinsulinemia on forearm glucose uptake and other metabolic responses in man. 287 53

The influence of a long-acting somatostatin octapeptide analogue (SMS 201-995) on splanchnic circulation and metabolism has been studied in healthy subjects and in patients with liver cirrhosis. In healthy subjects doses of 5, 10, 50, or 100 micrograms SMS and in the cirrhotic patients 25 micrograms SMS were infused intravenously during 1 h. Measurements were obtained before, during, and for 1 h after SMS infusion. SMS infusion in healthy subjects resulted in a 25-35% reduction in hepatic blood flow. This effect was largely independent of the dose used. Splanchnic oxygen uptake was unchanged before and during SMS infusion. Insulin and glucagon levels fell markedly in response to SMS administration, and the blood concentration and splanchnic output of glucose decreased transiently. Patients with liver cirrhosis responded to SMS infusion similarly to the healthy subjects. Hepatic blood flow decreased by 25-35% and remained suppressed for at least 1 h after infusion. Wedge hepatic venous pressure was 18 +/- 2 mm Hg in the basal state and decreased progressively during and after SMS infusion (60 min after infusion, 15 +/- 2 mm Hg; P less than 0.01). The marked hyperinsulinaemia and hyperglucagonaemia seen in the basal state decreased significantly during SMS administration. As in the case of the controls, blood concentration and splanchnic output of glucose fell transiently during and after SMS infusion. It is concluded that SMS exerts a marked and prolonged suppressive effect on hepatic blood flow in both healthy subjects and patients with liver cirrhosis.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:The influence of a long-acting somatostatin analogue on splanchnic haemodynamics and metabolism in healthy subjects and patients with liver cirrhosis. 287 92

This study examined the relationship between postnatal metabolic and hormonal changes and the accompanying rapid increase in mitochondrial adenine nucleotide content (ATP + ADP + AMP) in rabbit liver. The cytosolic NAD+/NADH concentration ratio, calculated from tissue pyruvate and lactate values, increased linearly 6.6-fold during the 1st postnatal h. The mitochondrial NAD+/NADH concentration ratio, calculated from tissue acetoacetate and beta-hydroxybutyrate values, increased 28-fold by 30 min postnatal. These changes in NAD+/NADH suggest that tissue oxygenation occurs rapidly and that oxygen supply rather than substrate supply is limiting for mitochondrial respiration in the immediate postnatal period. The normal increase in mitochondrial adenine nucleotide content that occurs within 2 h after birth was inhibited by hypoxia (5% O2). Glucagon stimulated the postnatal increase in mitochondrial adenine nucleotides but had no effect in combination with hypoxia. Both glucose and somatostatin injections inhibited the increase in mitochondrial adenine nucleotides and increased the insulin-to-glucagon ratio. Isoproterenol or dibutyryl cAMP stimulated, but propranolol did not inhibit, the normal increase in mitochondrial adenine nucleotide content. Phentolamine did not stimulate the postnatal accumulation of adenine nucleotides. In summary, the results show that the insulin-to-glucagon ratio is probably the most important hormone regulator of the rapid recompartmentation of adenine nucleotides into the mitochondrial matrix and that tissue oxygenation is strictly permissive for this hormone effect in the first 2 h after birth.
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PMID:Regulation of mitochondrial adenine nucleotide content in newborn rabbit liver. 289 2

Protease Re, a new cytoplasmic endoprotease in Escherichia coli, was purified to homogeneity by conventional procedures, using [3H]casein as the substrate. The enzyme consists of a single polypeptide of 82,000 molecular weight. It is maximally active between pH 7 and 8.5 and is independent of ATP. It has a pI of 6.8 and a Km of 10.8 microM for casein. Since diisopropyl fluorophosphate and phenylmethylsulfonyl fluoride inhibited this enzyme, it appears to be a serine protease. Protease Re was sensitive to inhibition by L-1-tosylamido-2-phenylethylchloromethylketone but not to that by 1-chloro-3-tosylamido-7-aminoheptanone, thiol-blocking reagents, chelating agents, or various peptide aldehydes. Re also degraded [125I]globin, [125I]glucagon, and 125I-labeled denatured bovine serum albumin to acid-soluble products (generally oligopeptides of greater than 1,500 daltons), but it showed no activity against serum albumin, growth hormone, insulin, or a variety of fluorometric peptide substrates. It also hydrolyzed oxidatively inactivated glutamine synthetase (generated by ascorbate, oxygen, and iron) four- to fivefold more rapidly than the native protein. Protease Re appears to be identical to the proteolytic enzyme isolated by Roseman and Levine (J. Biol. Chem. 262:2101-2110, 1987) by its ability to degrade selectively oxidatively damaged glutamine synthetase in vivo. Its role in intracellular protein breakdown is uncertain.
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PMID:Purification and characterization of protease Re, a cytoplasmic endoprotease in Escherichia coli. 289 28

The drugs, new and old, useful in the treatment of acute cardiac failure, are reviewed in the light of its pathophysiological mechanisms and of the biochemical aspects of myocardial contraction. Two major classes of drugs are considered, those that stimulate cell membrane adenylcyclase, i.e. beta-agonists (dopamine, dobutamine and dopexamine) and alpha-agonists (glucagon, forskolin, calcium agonists) and those that inhibit the cellular phosphodiesterases, i.e. bipyridine derivatives (amrinone and milrinone) and imidazolone derivatives (fenoximone and piroximone). Virtually, all the inotropic agents act by increasing the entry of calcium into the cell by increasing the intracellular AMPc concentration. Dopamine has a dose-related triphasic activity. At low doses, stimulation of renal dopaminergic receptors increases renal blood flow, glomerular filtration rate and sodium clearance. At moderate doses, dopamine stimulates, for the most part, cardiac beta-adrenergic receptors. Higher doses stimulate alpha-1-adrenergic receptors, with an increase in systemic arterial and venous pressures. Dobutamine exerts a potent positive inotropic action, with little effect on vascular tone and less tachycardia than with other catecholamines, resulting in only a slight increase in myocardial oxygen consumption. The dopamine analogue, dopexamine, increases renal blood flow, myocardial contractility and produces peripheral vasodilation. The haemodynamic effects of phosphodiesterase inhibitors are similar to those of dobutamine, except that these drugs are vasodilators, their positive inotropic properties are weak and their haemodynamic effects persist for at least 8 h after a single dose in heart failure patients.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:[Use of new inotropic agents in the treatment of acute cardiac failure]. 289 79

Local anaesthetic systemic toxicity is a rare but often dramatic complication of regional anaesthesia. Convulsions often follow warning signs, easily recognized when looked for; but they may occur from the first. They are rapidly followed by hypoxia and hypercapnia which greatly enhance the risk of severe cardiac depression, mainly with bupivacaine or etidocaine. Thiopentone is able to stop convulsions quickly, but may further depress the cardiovascular system. Diazepam has been shown to be effective in the treatment of local anaesthetic-induced convulsions. It gives less myocardial depression, but is much slower in effect. Midazolam, a new short-acting benzodiazepine, should be the best choice. Should tracheal intubation become necessary, suxamethonium can be used. Indeed, the principal use of these drugs is to make ventilation easier, so as to restore rapidly correct oxygenation. Severe cardiac depression, often leading to cardiac arrest, may occur from the first or after the appearance of convulsions. It generally follows a regional block carried out with bupivacaine. A few antiarrhythmic drugs have been used to treat ventricular arrhythmias, either in experimental studies (lidocaine, bretylium) or after clinical accidents (lidocaine). Their efficacy and innocuity have to be proved before they can be proposed to treat these accidents. Bradycardia only needs treatment with atropine when it causes severe haemodynamic disturbances. When cardiac arrest occurs, cardiopulmonary resuscitation must be carried out; its mainstays are: oxygen, sodium bicarbonate, adrenaline, calcium and perhaps glucagon. This must be continued for a long time, as late successes have been published.
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PMID:[How should a toxic accident be treated?]. 290 Jun 15

The effect of glucagon on hepatic regional hemodynamics was investigated in patients with chronic liver disease during peritoneoscopy with reflectance spectrophotometry. When glucagon was infused intravenously in patients with a non-cirrhotic liver, the regional hepatic tissue oxygen consumption, as estimated spectrophotometrically, increased significantly, whereas the index of hepatic tissue blood volume did not change appreciably, and consequently, the oxygen saturation of hemoglobin in the hepatic tissue blood decreased. In contrast, the administration of glucagon in patients with liver cirrhosis resulted in a significant increase in the index of hepatic tissue blood volume and produced a minor increase in hepatic tissue oxygen consumption. The oxygen saturation of hepatic blood hemoglobin tended to increase in the cirrhotics. The result suggests the presence of functional vasoconstriction at the presinusoidal and/or sinusoidal vessels in the cirrhotic liver, possibly due to a decreased vasomotor activity and/or an abnormal regulatory function of vasoactive substances, which are released by glucagon.
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PMID:Characterization of hepatic hemodynamics in cirrhotics and non-cirrhotics. Effect of glucagon infusion. 292 37


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