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Query: UNIPROT:P01275 (glucagon)
 26,492 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Circulating levels of insulin and glucagon, as well as their release from isolated pancreatic islets, have been measured in Zucker rats to examine the effect of genotype, sex and diet. The obese animals had higher plasma insulin levels and enhanced release from islets when compared to lean controls. Conversely, obese animals, despite no significant differences in fed plasma levels of glucagon, showed substantially reduced release from islets. Diet had no main effect on any of these parameters.
Horm Metab Res 1977 Sep
PMID:Insulin and glucagon: plasma levels and pancreatic release in the genetically obese Zucker rat. 33 2

Insulin on Escherichia coli was studied using wild type E. coli B/r and K12 strains and a number of phosphoenolpyruvate phosphotransferase mutants. In vivo, the effects of insulin on the differential rate of tryptophanase synthesis, the rate of alpha-methylglucoside uptake and the rate of growth on glucose were determined in E. coli B/r. In vitro, the effect of insulin on the adenylate cyclase and the phosphotransferase activities was determined using toluenized cell preparations of E. coli B/r, E. coli K12 and phosphotransferase mutant strains. The specificity of insulin action on E. coli was determined using glucagon, vasopressin and somatropin as well as insulin antisera. Results show the specific action of insulin on E. coli, inhibiting tryptophanase induction and adenylate cyclase activity, while stimulating growth on glucose and uptake and phosphorylation of alpha-methylglucoside.
Biochim Biophys Acta 1978 Sep 06
PMID:Insulin action on Escherichia coli. Regulation of the adenylate cyclase and phosphotransferase enzymes. 35 93

A case of islet cell hyperplasia in a ten year old black male with symptomatic fasting hypoglycemia was documented histopathologically. Provocative studies with glucose, tolbutamide, glucagon, and diazoxide were performed to test the insulin response of hyperplastic islets. The islets responded to glucose, glucagon, and tolbutamide. Diazoxide potentiated the tolbutamide-induced insulin response, and this effect of diazoxide was not blocked by propranolol. In the diagnostic work up of islet cell hyperplasia, dizoxide may paradoxically potentiate tolbutamide-induced insulin release, a finding which may falsely suggest progression of the disease.
Acta Paediatr Scand 1978 Sep
PMID:Paradoxical enhancement of tolbutamide-induced insulin release by diazoxide in a patient with islet cell hyperplasia. 35 39

In order to investigate whether patients with long-standing juvenile diabetes mellitus (onset of diabetes before the age of 30) and a low daily insulin requirement (less than 0.50 units/kg body weight) still have functioning B-cells, plasma C-peptide was determined after stimulation (OGTT and glucagon/tolbutamide) in 64 patients with diabetes of more than 18 years' duration (mean 31 years). Measurable endogenous insulin production was found in 24% of the patients. The prevalence of severe retinopathy was lower in the secretors than in the non-secretor group. There was no difference in insulin antibody concentration between the two groups. Furthermore, the insulin requirement in the secretor group was relatively constant during the course of diabetes. Metabolic control was similar in both groups. It is concluded that a persisting but low activity of endogenous insulin production can be found in many long-term juvenile diabetics with a low insulin requirement, while others without any residual beta-cell function develop a low insulin requirement for unknown reasons.
Diabetologia 1978 Sep
PMID:Persistent insulin secretion, assessed by plasma C-peptide estimation in long-term juvenile diabetics with a low insulin requirement. 35 94

The present study was conducted to determine if glucagon release is involved in the hyperglycemic response to epinephrine and isoproterenol in the fasted and fed, unanesthetized rabbit. Epinephrine produced dose-related increases in plasma glucose and glucagon levels in fed and fasted rabbits whereas isoprotereol produced modest hyperglycemia without hyperglucagonemia. Infusion of somatostatin suppressed epinephrine-induced glucagon release and this was correlated with a 50% reduction in the hyperglycemic response. These data suggest that epinephrine-induced glucagon release is the primary reason for the difference in hyperglycemic activity between epinephrine and isoproterenol in the unanesthetized rabbit.
Horm Metab Res 1978 Sep
PMID:Catecholamine-induced changes in plasma glucose, glucagon and insulin in rabbits: effects of somatostatin. 36 31

Glucagon can depress normal animal and human pancreatic exocrine secretions and modify experimentally-induced pancreatitis in animals. It has yet to be demonstrated that glucagon has any efficacy in the treatment of the diseased pancreas in man. Glucagon might act on the exocrine pancreas by 1. reducing pancreatic blood flow, 2. decreasing gastric secretion, 3. lowering serum calcium levels by the release of calcitonin, 4. acting to inhibit the secretin mechanism, 5. causing a hyperglycemia and 6. degranulating pancreatic acinar cells. While a reduction in pancreatic blood flow, an inhibition of the secretin mechanism and a hyperglycemia seemed to have been ruled out as possible mechanisms of action, there is too little available data to effectively speculate on the mechanism(s) of action of glucagon on the exocrine pancreas.
Am J Gastroenterol 1978 Sep
PMID:The effect of glucagon on the exocrine pancreas. A review. 36 5

To study insulin-glucagon interrelationships in the regulation of pancreatic islet functions, glucose-mediated insulin and glucagon secretion have been studied in isolated pancreatic islets from fed and from 4 and 8-day fasted rats. At low glucose levels (50 mg %) a continuous decrease of insulin and increase of glucagon secretion were observed during prolonged fasting. High glucose concentrations 300 mg %) stimulated insulin and inhibited glucagon secretion until 4 days, but did not cause any effect after 8 days fasting. These results suggest that the secretory mechanisms of the two hormones may have a common basis.
Rev Esp Fisiol 1978 Sep
PMID:Effect of prolonged fasting upon insulin and glucagon secretion from isolated rat pancreatic islets. 36 63

Arginine infusion tests were carried out in seven patients with pheochromocytoma before and after extirpation of the tumors in order to evaluate pancreatic islet alpha- and beta-cell function during the state of endogenous catecholamine excess. Six of the patients had glucose intolerance; one did not. Preoperatively, the pancreatic glucagon response was suppressed, while the insulin response was comparable to that in normal control subjects. Plasma glucose levels decreased rapidly after the beginning of arginine infusion in all patients. Theses changes during the infusion were evident in the one patient without glucose intolerance. Postoperatively, the glucagon response and plasma glucose changes were normalized. In addition to the obvious suppression of pancreatic alpha-cell function in our patients with pheochromocytoma, it seems likely that pancreatic beta-cell function also was suppressed; there was no enhancement of the insulin response to arginine during the period of chronic hyperglycemia, a situation in which a synergistic effect between glucose and arginine might be expected.
J Clin Endocrinol Metab 1979 Sep
PMID:Pancreatic alpha- and beta-cell function in pheochromocytoma. 38 21

To clarify further the etiology of the carbohydrate intolerance in idiopathic hemochromatosis, we investigated the glucose, insulin, C-peptide, and glucagon responses to arginine (0.5 g/kg) infused during 30 min in lean normal subjects; in insulin-requiring subjects with hemochromatosis, genetic diabetes, and total pancreatectomy; and in nondiabetic cirrhotic subjects without portosystemic shunting. Serum insulin, C-peptide, and glucagon responses (30K antibody) were determined by RIA, and glucose level was determined by a glucose oxidase technique. Hemochromatotic and genetic diabetic subjects had similar basal glucose (157 +/- 25 vs. 168 +/- 40 mg/dl) and C-peptide (0.73 +/- 0.42 vs. 0.65 +/- 0.22 ng/ml) values, with subnormal C-peptide peak responses to stimulation (1.05 +/- 0.38 and 1.40 +/- 0.83 vs. 3.95 +/- 0.4 ng/ml in normals; P less than 0.05). No glucagon or C-peptide response to arginine was seen in any pancreatectomized subject. Similar but excessive glucagon levels were present in hemochromatosis, diabetes, and cirrhosis under basal conditions (166 +/- 24, 232 +/- 111, and 263 +/- 116 vs. 76 +/- 15 pg/ml; P less than 0.05) and after arginine stimulation (782 +/- 80, 834 +/- 123, and 902 +/- 275 vs. 489 +/- 81 pg/ml; P less than 0.05) when compared with normals. The excessive glucagon levels found in hemochromatosis, diabetes mellitus, and cirrhosis contrast to the absent response in pancreatectomized subjects and indicate that generalized islet cell destruction is not the major factor in diabetic hemochromatotic subjects.
J Clin Endocrinol Metab 1979 Sep
PMID:Pancreatic alpha-cell function in diabetic hemochromatotic subjects. 38 22

The influence of previous exposure to glucose on the subsequent B- and A(2)-cell secretory responses to arginine was investigated in the perfused pancreas of the rat. Arginine (8 mM) was administered in two brief (9 min) pulses separated by a period of 66 min. In pancreata from 18-h-fasted animals the two pulses of arginine elicited biphasic glucagon secretory responses, while stimulation of insulin release was barely detectable. When 27.7 mM glucose was administered for 30 min during the intervening period up to 20 min before the second pulse of arginine, the glucagon response to arginine was diminished by 55% while the insulin release was markedly increased in comparison with the first pulse. 8.3 mM glucose, when administered before the second pulse of arginine, exerted effects that were smaller but otherwise similar to those of 27.7 mM glucose.The inclusion of 3.9 mM glucose during the stimulation periods with arginine decreased the glucagon and greatly increased the insulin secretory response. Under these conditions, previous exposure to 27.7 mM glucose inhibited the glucagon and enhanced the insulin response to the second stimulatory pulse of arginine to the same relative degree as when arginine was administered alone. Diazoxide (2 mM), when administered together with 27.7 mM glucose, almost completely inhibited insulin release induced by the presence of glucose, yet did not influence the modulation exerted by glucose on the subsequent insulin and glucagon secretory response to arginine. Conversely, these effects of the glucose pulse could not be reproduced by 1 mug/ml of porcine insulin. Previous exposure to glyceraldehyde (10 mM) mimicked the glucose effects.Also, in pancreata from fed rats, previous exposure to 27.7 mM glucose markedly inhibited subsequent arginine-induced glucagon secretion while the concomittant insulin response was enhanced.IT IS CONCLUDED THAT: (a) both A(2)- and B-cell responsiveness is modulated by a previous exposure to glucose which produces opposite effects in the two cell types, (b) this action of glucose does not depend on its insulin-releasing capacity, and (c) instead, a "memory" of glucose is induced as a consequence of the metabolism of the sugar in the A(2) and B cells.
J Clin Invest 1979 Sep
PMID:Glucose memory of pancreatic B and A2 cells: evidence for common time-dependent actions of glucose on insulin and glucagon secretion in the perfused rat pancreas. 38 26


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