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)

Glucagon-stimulated adenylyl cyclase activity has been shown to change in liver membranes manipulated to alter either their fatty acid composition or fluidity. We examined whether membrane alterations induced by dietary manipulation affected receptor function. Glucagon- and beta-adrenergic-stimulated receptor-adenylyl cyclase systems were examined in liver membranes of rats fed diets containing 10% corn oil, 10% coconut oil (essential FFA deficient), or 8.5% coconut oil with 1.5% corn oil (essential FFA repleat). Basal and maximal nonreceptor-mediated adenylyl cyclase activity (stimulated by NaF, guanylylimidodiphosphate, and forskolin) was the same in membranes of each of the dietary groups, suggesting that Gs-protein and the catalytic unit activity per se were unaltered by the manipulations. Glucagon-stimulated adenylyl cyclase activity increased with increasing unsaturation of dietary fatty acids; activity in coconut oil-fed rats was 527 +/- 30 (mean +/- SEM) pmol/mg.10 min, that in coconut/corn oil-fed rats was 752 +/- 74 pmol/mg.10 min, and that in corn oil-fed rats was 981 +/- 94 pmol cAMP/mg.10 min. [125I]Monoiodoglucagon binding did not increase in parallel to the adenylyl cyclase alterations; coconut oil-fed animals (614 fmol/mg) differed from the other groups (450 and 430 fmol/mg). Isoproterenol (beta-adrenergic)-stimulated adenylyl cyclase activity was also highest in the corn oil-fed animals, but was similar in the other dietary groups, with no difference in other characteristics of [125I]iodopindolol binding between the groups. The results demonstrate that alterations in the glucagon-stimulated adenylyl cyclase response are different from those in the beta-adrenergic adenylyl cyclase response. Further, they suggest that although direct activations of the catalytic unit or its interaction with the guanine nucleotide-sensitive protein are apparently not affected, hormone receptor-mediated adenylyl cyclase activity may be altered by these dietary manipulations.
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PMID:Altered glucagon- and catecholamine hormone-sensitive adenylyl cyclase responsiveness in rat liver membranes induced by manipulation of dietary fatty acid intake. 222 11

Patients with anorexia nervosa occasionally suffer from hypoglycemic comas. We investigated the role of human pancreatic polypeptide (HPP) in insulin-induced hypoglycemia (0.1 U/kg of regular insulin). Ten female patients with anorexia nervosa (20.7 +/- 2.0 years, mean +/- SEM; 34.9 +/- 1.7 kg, mean +/- SEM) and 8 age-matched female controls (20.9 +/- 0.6 years, 51.5 +/- 0.8 kg) were tested. In the patients with anorexia nervosa, testing was performed before and after the restoration of body weight (45.0 +/- 0.8 kg). There was no significant difference in glucose nadir between patients with anorexia nervosa and the control subjects. However, glucose recovery from nadir was delayed in patients with anorexia nervosa. In anorexia nervosa patients, the plasma pancreatic glucagon responses to insulin-induced hypoglycemia did not differ from those of the controls. Results also showed, however, that HPP responses to insulin-induced hypoglycemia were significantly higher in patients with anorexia nervosa than in controls (p less than 0.01). The increased HPP responses were still present after the restoration of body weight in anorexia nervosa patients. A complete body weight recovery or a longer period of time may be required to normalize the HPP response to insulin-induced hypoglycemia in patients with anorexia nervosa, after the restoration of body weight.
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PMID:Human pancreatic polypeptide responsiveness to insulin-induced hypoglycemia in anorexia nervosa. 227 11

Disturbances of gastrointestinal motility are a common feature of diabetes mellitus and are usually ascribed to autonomic neuropathy. In order to assess the role of other factors on changes in motility in diabetes we have studied the stomach to caecum transit time (SCTT) during the progression of streptozotocin induced diabetes in the rat. Rats were used one, two, four, and eight weeks after a single injection of streptozotocin and age matched animals were used as controls. In further experiments non-diabetic rats received a bolus injection of pancreatic glucagon (50 or 75 micrograms intraperitoneally) or its diluent. SCTT was estimated using the non-invasive hydrogen excretion method. SCTT was unaffected by the age of the animal (mean (SEM) value: 101 (5) min), but was significantly delayed at one week (139 (11) min, p less than 0.01), two weeks (163 (16) min, p less than 0.01), four weeks (148 (9) min, p less than 0.01), and eight weeks (171 (13) min, p less than 0.01) after streptozotocin. SCTT was also slower during hyperglucagonaemia (control 96 (6) min; glucagon treated 50 micrograms: 120 (7) min, p less than 0.05 and 75 micrograms: 127 (8), p less than 0.05). Since autonomic neuropathy is not a recognised feature of the initial stages of diabetes hyperglucagonaemia may be responsible, at least in part, for diabetes induced changes in gastrointestinal motility.
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PMID:Delayed stomach to caecum transit time in the diabetic rat. Possible role of hyperglucagonaemia. 237 69

We studied the effects of intravenous infusion of synthetic oxyntomodulin (proglucagon 33-69), a potential hormone from the ileal mucosa, on fasting and postprandial gastric acid secretion, gastric emptying, gastroduodenal motility, and pancreatic secretion of trypsin and lipase measured simultaneously in six normal volunteers using multilumen tubes for infusion of markers, manometry, and aspiration of gastric and duodenal contents. The infusion resulted in plasma concentrations of 203 +/- 21 pmol/liter (mean +/- SEM) of oxyntomodulin, regarded as high but not unphysiological concentrations of the peptide. Oxyntomodulin almost abolished basal acid secretion and inhibited postprandial acid secretion by 35 +/- 10%. Gastric emptying decreased significantly; the time for 50% to leave the stomach increased from 17.3 +/- 2.2 min to 34.7 +/- 8.0 min. The postprandial gastroduodenal motility was massively inhibited by oxyntomodulin. Postprandial trypsin and lipase output was significantly inhibited by 56 +/- 12% and 42 +/- 11%, respectively, during oxyntomodulin infusion. However, pancreatic enzyme output was linearly related to gastric emptying and oxyntomodulin did not influence this relationship, suggesting that oxyntomodulins effect was due to its effect on gastric emptying. Oxyntomodulin seems to play an important role in the small intestinal inhibitory control of gastropancreatic functions.
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PMID:Oxyntomodulin from distal gut. Role in regulation of gastric and pancreatic functions. 267 Apr 87

Glucagon and insulin metabolism was studied in 9 cirrhotic patients and 4 non-cirrhotic controls. Net output of glucagon and insulin into portal circulation was calculated from difference between portal venous and systemic arterial concentrations multiplied by portal plasma flow. Metabolic clearance rate was also calculated as the ratio of the output to systemic concentration. Portal blood flow was measured by the continuous local thermodilution method. The results were as follows: 1) Arterial glucagon concentration was elevated in liver cirrhotics compared with non-cirrhotic-controls. Glucagon output in cirrhotics was higher than in controls [46.3 +/- 11.8 vs. 13.2 +/- 2.5 ng/min (mean +/- SEM), p less than 0.05]. Metabolic clearance rate of glucagon was not significantly different between the two groups. 2) There was a significant correlation between glucagon output and portal venous concentration of norepinephrine (r = 0.625, p less than 0.05). 3) Insulin levels in systemic arterial blood were higher in cirrhotic patients than non-cirrhotic subjects. Insulin output was not significantly different between the two groups, however, metabolic clearance rate of insulin in cirrhotics was reduced in comparison with the controls (274.5 +/- 44.3 vs. 557.7 +/- 108.6 ml/min, p less than 0.05).
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PMID:[The implication of hyperglucagonemia and -insulinemia in liver cirrhotics]. 267 48

To study whether hyperthermia reproduces hormonal and metabolic responses seen in stress states such as mild infections, six normal male subjects underwent (i) a 3-h hot bath and (ii) a 3-h thermoneutral control period. During the hot bath body temperature rose by 1.2 +/- 0.03 degrees C (mean +/- SEM) and significant peaks of circulating growth hormone (56 +/- 9 vs 7 +/- 4 mU/l), adrenaline (310 +/- 34 vs 152 +/- 39 pmol/l), glucagon (19.2 +/- 4.3 vs 11.8 +/- 2.3 pmol/l) and cortisol were recorded together with slight hyperinsulinaemia (6.5 +/- 1.3 vs 5.3 +/- 1.0 mU/l, P less than 0.05). Hyperthermia was also accompanied by significant increases in circulating levels of free fatty acids (0.93 +/- 0.1 vs 0.46 +/- 0.1 mmol/l), 3-hydroxybutyrate (196 +/- 67 vs 50 +/- 18 mumol/l), glycerol (102 +/- 10 vs 48 +/- 5 mumol/l) and lactate. Blood alanine decreased and blood glucose remained constant. When an intravenous glucose tolerance test was performed during the last hour of hyperthermia signs of impaired first phase and enhanced second phase insulin responses were recorded. Calculated values for glucose disappearance also deteriorated (1.34 +/- 0.19 vs 2.04 +/- 0.50 %/min, P less than 0.05). We conclude that hyperthermia mimics most major metabolic and hormonal changes observed during mild infection and could provide a model to study these conditions.
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PMID:Metabolic and hormonal responses to exogenous hyperthermia in man. 268 66

The effect of insulin induced hypoglycemia on glucoregulatory hormones and intermediary substrates was studied in four infants (three boys and one girl, ages 12-89 days) with persistent hyperinsulinism secondary to nesidioblastosis (two) or microadenoma of the pancreas (two). During the "fasting test" the following data expressed as mean basal plasma values +/- SEM vs. mean hypoglycemic values +/- SEM were obtained: insulin (57.3 +/- 17.9 vs. 27.5 +/- 10.6 microU/ml), C-peptide (4.9 +/- 1.1 vs. 3.5 +/- 0.9 ng/ml), free fatty acids (0.30 +/- 0.01 vs. 0.32 +/- 0.02 mmol/l), beta-hydroxybutyrate (less than 0.03 vs. 0.05 +/- 0.02 mmol/l), alanine (204.0 +/- 67.5 vs. 228.3 +/- 64.9 mumol/l), lactate (5.3 +/- 0.7 vs. 5.4 +/- 1.1 mg/dl), pyruvate (41.3 +/- 4.8 vs. 19.7 +/- 4.2 mg/dl). These data suggest "inappropriate" elevation of insulin and C-peptide levels, inhibition of lipolysis and lack of gluconeogenic substrates secondary to endogenous HI. An increase of cortisol (6.5 +/- 4.1 vs. 16.3 +/- 5.7 micrograms/dl), adrenaline (0.015 +/- 0.05 vs. 0.25 +/- 0.24 ng/ml) (3 out of 4) and noradrenaline (0.28 +/- 0.06 vs. 0.64 +/- 0.14 ng/ml) was noted, whereas only minute increase was found for glucagon (134.3 +/- 51.7 vs. 177.0 +/- 76.2 pg/ml) and HGH (5.7 +/- 1.1 vs. 7.1 +/- 1.1 ng/ml). Although some stimulation of neonatal glucoregulatory hormones was evident, this was not strong enough for counteracting endogenous HI.
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PMID:[Diagnostic evaluation of persistent neonatal hypoglycemia using the fasting test: behavior of glucoregulatory hormones and intermediary metabolites (1)]. 282 19

1. The effect of acetate absorbed from the gut on glucose turnover has been determined in four healthy subjects during both fasting and an intravenous glucose infusion by using [U-13C]glucose. 2. In the first part of the study, after an overnight fast, a tracer dose of [U-13C]glucose was infused at a constant rate along with an infusion of saline for 7 h. In the second part the saline infusion was replaced by glucose at 4.25 mg min-1 kg-1. In both studies 15 mmol of sodium acetate was given by mouth at 15 min intervals from the fourth to the sixth hour. Glucose turnover, respiratory quotient, metabolic rate and blood levels of acetate, 3-hydroxybutyrate, lactate, insulin, glucagon and gastric inhibitory polypeptide were measured. 3. Glucose turnover rates (means +/- SEM) were 1.88 +/- 0.1 mg min-1 kg-1 during fasting and 4.0 +/- 0.08 mg min-1 kg-1 during glucose infusion. Acetate had no effect on glucose turnover, insulin, glucagon and gastric inhibitory polypeptide levels, but temporarily halted the rise in free fatty acids seen during the fasting study. No changes in oxygen consumption or carbon dioxide output occurred, in keeping with previous observations that acetate substitutes for lipid oxidation during metabolism and has no direct effect on glucose turnover.
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PMID:Effect of gut-derived acetate on glucose turnover in man. 284 53

Neuroglucopenia (NGP), which is a serious potential hazard for all insulin-treated diabetics, stimulates many neural and hormonal responses including increased glucagon secretion and activation of beta-adrenergic receptors of the autonomic nervous system. To determine which of these responses is important in recovery from NGP, we induced NGP in baboons by the intravenous (IV) injection of 2-deoxy-D-glucose with and without beta-adrenergic blockade (propranolol) and somatostatin. Thirty minutes after the induction of NGP the animals recovered, and the mean (+/- SEM) rise in arterial plasma glucose was 6.6 +/- 0.9 mmol/L, in glycerol 0.106 +/- 0.22 mmol/L, and in beta-hydroxybutyrate 0.091 +/- 0.22 mmol/L. Animal recovery and glucose rise were uninfluenced by the infusion of propranolol (mean 30 minute plasma glucose rise of 6.2 +/- 0.8 mmol/L) and somatostatin (6.8 +/- 0.8 mmol/L). However, the combined infusion of somatostatin and propranolol prevented animal recovery and glucose rise (1.0 +/- 0.1 mmol/L). The glycerol and beta-hydroxybutyrate rises were blocked by the propranolol infusion alone. Thus, recovery from NGP and the associated rise in plasma glucose, glycerol, and beta-hydroxybutyrate are prevented by the combination of the suppression of the glucagon and beta-adrenergic response to NGP. Furthermore, if the results of our study are extrapolated to insulin-dependent diabetic patients, most of whom have an impaired glucagon response to insulin-induced hypoglycemia/neuroglucopenia, they would be critically dependent on beta-adrenergic mechanisms for recovery from NGP.
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PMID:Glucose counterregulation during recovery from neuroglucopenia: which mechanism is important? 285 49

Specific somatostatin (SRIH) receptors on human pituitary adenoma cell membranes were characterized using [125I]Tyr11-SRIH as the radioligand. Specific binding of [125I] Tyr11-SRIH to adenoma cell membranes reached a steady state within 30 min at 25 C, and semilogarithmic analysis of the data revealed that the rate of the binding was linear at 25 C with a t1/2 of 13.2 min. Specific binding increased linearly with 5-160 micrograms plasma membrane protein. SRIH-14 and SRIH-28 inhibited [125I]Tyr11-SRIH binding to adenoma cell membranes with ID50S of 0.32 and 0.50 nM, respectively, while secretin, glucagon, gastrin, cholecystokinin-8, bombesin, TRH, LHRH, human GH-releasing factor-(1-44)-NH2, D-Ala2-met-enkephalin, gamma-aminobutyric acid and taurine did not significantly inhibit binding. All of 13 GH-secreting adenomas investigated had specific and high affinity SRIH receptors, with a dissociation constant (Kd) of 0.80 +/- 0.15 nM (mean +/- SEM) and a maximal binding capacity (Bmax) of 234.2 +/- 86.9 fmol/mg protein (mean +/- SEM). Among five of the nonsecreting pituitary adenomas examined, two had SRIH receptors with Kd values of 0.18 and 0.32 nM and Bmax values of 17.2 and 48.0 fmol/mg protein, respectively. In the remaining three, SRIH receptors were not detected. These results indicate that GH-secreting adenomas as well as some nonfunctioning adenomas have specific SRIH receptors, and hence, the function of the adenomas could be altered by SRIH.
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PMID:Specific somatostatin receptors on human pituitary adenoma cell membranes. 286 81


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