UNIPROT:P01275 - FACTA Search

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

In an attempt to clarify the role of endogenous opioid peptides in substrate mobilization and hormonal responses to dynamic exercise, eight trained cyclists completed exercise trials at 90% of maximal O2 consumption (VO2max) until exhaustion and at 70% VO2max for 90 min. Trials were conducted after intravenous administration of the opiate antagonist naloxone (NAL, 0.1 mg/kg bolus + 0.1 mg.kg-1.h-1) or volume-matched saline (SAL) at each intensity. Serum glucose was maintained at significantly higher levels at 60 and 90 min of exercise in the 70%-NAL than in the 70%-SAL trial and at all points during exercise and at 30 and 60 min of recovery in the 90%-NAL than in the 90%-SAL trial. The serum insulin response to exercise was not altered by NAL administration at either intensity. Serum C-peptide was approximately 50% higher at 60 and 90 min of exercise in the 70%-NAL than in the 70%-SAL trial but was significantly lower during exercise in the 90%-NAL than in the 90%-SAL trial. The plasma glucagon response to exercise at 70% VO2max was not altered by NAL administration but was significantly elevated in the 90%-NAL vs. the 90%-SAL trial. Plasma epinephrine was 50-150% (approximately 2-3 nM) higher during exercise from 30 to 90 min of exercise in the 70%-NAL than in the 70%-SAL trial and was higher at termination (4.9 +/- 2.1 vs. 2.7 +/- 1.7 nM) in the 90%-NAL than in the 90%-SAL trial, although the difference in the 90% trial was not statistically significant.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Opioid antagonism alters blood glucose homeostasis during exercise in humans. 792 70

To elucidate the pathogenesis of diabetes in spontaneously diabetic Chinese hamsters (CHAD strain), a longitudinal study from just after weaning to overt diabetic state was performed. Fasting and non-fasting plasma glucose, non-fasting plasma insulin and pancreatic hormone contents (insulin, glucagon and amylin) were measured, and light microscopic examination of pancreatic islets by immunohistochemical technique and pancreas perfusion study were performed. No insulitis was found in the islets of the CHAD strain. In animals aged 1 month, there was no significant difference in the percentage of B-cell area to islet area between the CHAD strain and the control. At this stage, hyperinsulinemia was observed despite normal plasma glucose levels both in fasting and non-fasting states. In the animals of the CHAD strain aged 2-4 months, insulin secretion from the pancreas, pancreatic insulin content and non-fasting plasma insulin level decreased in proportion to the decrease of B-cell mass. In animals aged about ten months, severe hyperglycemia and hypoinsulinemia were observed. We demonstrated the existence of amylin-like immunoreactivity in the B-cells of Chinese hamsters. However, no amyloid deposit was observed in the islets of the CHAD strain. After the onset of diabetes, amylin secretion from the pancreas and pancreatic amylin content in the CHAD strain were significantly lower than those in the control. We demonstrated the natural history of B-cell dysfunction in the CHAD strain. It could mean the process of B-cell exhaustion. The profile of the CHAD strain is similar to some types of human NIDDM. Therefore, the CHAD strain is a useful diabetic model in the study of NIDDM.
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PMID:Natural history of B-cell dysfunction in spontaneously diabetic Chinese hamsters. 798 44

We hypothesized that augmented responses of glucoregulatory hormones in iron deficiency would enhance liver and muscle glycogenolysis, leading to increased gluconeogenic precursor (lactate) supply and upregulation of hepatic gluconeogenesis. Female weanling rats were randomly placed on either a mildly iron-deficient (-Fe; 15 mg Fe/kg diet) or an iron-sufficient (+Fe; 50 mg Fe/kg diet) diet for 4 wk and studied at rest and during exhaustive treadmill running. Hemoglobin was 9.0 +/- 0.2 and 13.1 +/- 0.3 g/dl in -Fe and +Fe, respectively, after 3.5 wk of dietary iron deficiency. Arterial plasma epinephrine (Epi), norepinephrine (NE), adrenocorticotropic hormone (ACTH), corticosterone, insulin, and glucagon levels were similar at rest in both groups, as were liver, gastrocnemius, and superficial and deep vastus medialis glycogen levels. Liver and kidney phosphoenolpyruvate carboxykinase (PEPCK) activities were similar in both groups. Maximum O2 consumption was decreased (22%) in -Fe. Respiratory exchange ratio (CO2 production/O2 consumption) was unaffected at rest but increased at maximum O2 consumption in -Fe. Time to exhaustion during a standardized running test (13.4 m/min, 0% grade) was decreased 45% in -Fe (63 +/- 5 vs. 116 +/- 10 min). During exercise, euglycemia was maintained in both groups, but blood lactate was elevated in -Fe. The mean net glycogen utilization during exercise was increased in liver (43%), soleus (33%), and superficial vastus medialis (106%) and decreased in the gastrocnemius (36%) in -Fe. Liver and kidney PEPCK activities were increased similarly at exhaustion in both groups.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Augmented glucoregulatory hormone concentrations during exhausting exercise in mildly iron-deficient rats. 823 58

The present investigation was conducted to study metabolic and hormonal responses to prolonged exercise to exhaustion in insulin-dependent diabetic subjects. Sixteen healthy subjects (control) and 15 diabetics with no-insulin administration for 12 hours were studied. They were submitted to short-term exercise to exhaustion on a cycle ergometer at 55% to 60% of maximum oxygen consumption (VO2max). Exercise tolerance was significantly lower in diabetic subjects (66 +/- 6.7 v 117 +/- 9.4 minutes), and glucose concentration was significantly higher in these subjects. At exhaustion, only diabetic subjects showed a significant decrease in glycemia (142 +/- 20 v 111 +/- 16 mg/dL). Lactate concentration increased significantly during exercise up to 30 minutes, but at exhaustion only control subjects showed a reduction. No significant difference in free fatty acid (FFA) concentrations was observed between the groups during a 30-minute exercise period; however, at exhaustion levels were significantly higher in control subjects. Prolactin and C-peptide concentrations were significantly lower in diabetic subjects, whereas glucagon concentration was higher. No significant differences between the groups were observed for cortisol and growth hormone (GH) concentrations. We conclude that (1) diabetic subjects show reduced exercise tolerance when no insulin is administered for 12 hours, and (2) exercise to exhaustion reduces serum glucose concentrations in insulin-dependent diabetics.
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PMID:Exercise tolerance is lower in type I diabetics compared with normal young men. 847 16

Most of diabetics have no symptoms and chemical analyses may be sole way to diagnose the disease itself and its complications. Chemical analyses are also important to assess the propriety of glycemic control during every possible treatment of diabetes. Some markers for long-term glycemic control other than glucose concentration may be also used as a screening methods for glucose intolerance. HbA1c is established for long term as a marker for glycemic control but still large interlaboratory variation is present. Fructosamine is measured by a simpler procedure but many deoxidizing materials in serum especially superoxide may interfere with the reaction. Glycated albumin should be more reliable than fructosamine but a standard method of measurement has not been established yet. The decrease in serum 1,5-anhydro-D-glucitol(1,5-AG) is very sensitive to urinary glucose excretion and may be useful as a marker of glycemic control and diagnosis of diabetes. Discrimination of Type I(IDDM) from Type II(NIDDM) in Japanese diabetic patients is sometimes very difficult and evidences of autoimmunity by anti-glutamic acid decarboxylase(GAD) antibody and of exhaustion of insulin secretion by C-peptide measurement 6min after combined infusion of 1mg of glucagon and 20ml of 50% glucose are the few methods to diagnose. Early diagnosis of diabetic complication is another important point of clinico-chemical determinations. Usually, each diabetic complication progresses in parallel. Micro-measurement of urinary transferrin is one of the most sensitive methods likewise urinary microalbumin measurement. Future measurement of advanced glycation end product (AGE) may also tell us if patients are suffering from diabetic complications or if one is suffering from diabetes or not.
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PMID:[Recent progress in diagnoses of diabetes and its complications]. 856 34

The effect of the type of venous drainage of the graft on its endocrine function was studied in two groups of pigs after segmental pancrease autotransplantation. Group 1 comprised 10 pigs with portal venous drainage (PVD) and group 2 comprised 10 pigs with systemic venous drainage (SVD). The graft consisted of body and tail of the pancreas. The pigs were totally pancreatectomized. The pancreatic duct was occluded by neoprene injected into the duct. One week before and 1 and 3 months after transplantation, intravenous glucose tolerance (IVGTT) and meal stimulation tests (MST) were performed. Plasma glucose (PG), insulin (INS), C-peptide, glucagon (GLU),and pancreatic polypeptide (PP) were measured during the tests. All pigs had normal fasting PG, 1 and 3 months after PanTx, although MST disclosed significantly higher PG (P<0.05) during the test after transplantation. In the PVD group, a decrease in INS level during both test was recorded after PanTx (P<0.05), while in the SVD group a nonsignificant rise in INS level was recorded compared with before transplant. A significant difference (P<0.05) in INS levels were present both 1 and 3 mon. after PanTx between the two groups. Pigs with PVD showed a higher (P<0.05) C-peptide level than pigs with SVD during IVGTT. The initial significant rise in PP during MST and the initial fall in PP during IVGTT recorded in all pigs before transplantation were totally lost after transplantation in both groups. During the tests, PP remained steady and significantly lower than the pretransplantation levels in both groups. A significantly higher GLU level during both IVGTT and MST was observed in SVD compared with PVD 1 month after PanTx (P<0.05), being more pronounced during MST. This accentuated GLU concentration decreased by 3 months after transplantation, although it was still significantly greater than pretransplantation levels. We concluded that the unnatural mode of delivery of pancreas endocrine secretion to systemic rather than to portal circulation leads to derangements in pancreatic endocrine function in order to maintain glucose homeostasis. This may cause earlier exhaustion of islet cells. Segmental rather than whole organ and duct occlusion rather than exocrine drainage may further contribute to this, shortening the effective life of the graft.
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PMID:Pancreas autotransplantation in pig with systemic or portal venous drainage. Effect on the endocrine pancreatic function after transplantation. 862 76

The influences of food deprivation and refeeding on glutathione (GSH) status, antioxidant enzyme activity and lipid peroxidation in response to an acute bout of exercise were investigated in the liver and skeletal muscles of male Sprague-Dawley rats randomly divided into three groups: starved for 48 h without refeeding; starved for 48 h and refed for 24 or 48 h. Half of each group of rats was exercised on a treadmill until exhaustion and killed immediately, whereas the other half group was killed at rest. Food-deprived rats had significantly lower liver GSH concentration and GSH:glutathione disulfide (GSSG) ratio. Malondialdehyde concentrations in the liver and skeletal muscle were both higher in the starved than in the refed rats (P < 0.05). Refed rats had significantly greater liver GSH level, gamma-glutamylcysteine synthetase and glucose 6-phosphate dehydrogenase activities and plasma insulin concentration than unfed rats. Exercised 24- and 48-h refed rats had 27% and 31 % lower liver GSH (P < 0.05), respectively, and a 21 % lower GSH:GSSG ratio (P < 0.05) than their rested counterparts. Plasma insulin concentrations were significantly lower, whereas glucagon concentrations were greater in the exercised than in the rested rats. Muscle GSH concentration was significantly lower in the food-deprived than in the refed rats (P < 0.05) but was unaffected by exercise. Exercised 24-h refed rats had significantly elevated muscle GSSG concentration compared with rested rats, along with a higher GSH peroxidase and a lower gamma-glutamyltranspeptidase activity (P < 0.05). These data indicate that both food deprivation-refeeding and exhaustive exercise influence liver and skeletal muscle glutathione status and that these changes may be controlled by hepatic glutathione synthesis and release due to hormonal stimulation.
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PMID:Alteration of glutathione and antioxidant status with exercise in unfed and refed rats. 868 45

In sea-level natives, exposure to hypoxia for a few weeks is characterized by an increased dependence on blood glucose and a decreased reliance on lactate for energy metabolism during exercise. These metabolic adjustments have been attributed to behavioral changes in the sympathoadrenergic and pancreatic systems. The aim of this study was to test the hypothesis of a reduced sympathoadrenergic activation and subsequent metabolic changes when high-altitude natives are acutely exposed to normoxia. Young Andean natives performed incremental exercise to exhaustion during hypoxia (arterial PO2 55.1 +/- 1.1 Torr) or during acute normoxia (arterial PO2 78.7 +/- 1.7 Torr). As a whole, oxygen uptake was increased in normoxia compared with hypoxia during graded exercise. This finding is not related to a decrease in anaerobic metabolism but rather is interpreted as a consequence of a shift in substrate utilization during exercise (increased contribution of fat as assessed by a reduction in the respiratory exchange ratio). These metabolic changes are not accompanied by modifications of glucoregulatory hormones (catecholamines, insulin, and glucagon). In particular, the exercise-induced catecholamine secretion was similar in chronic hypoxia and acute normoxia. As a consequence, blood lactate accumulation during incremental exercise was similar in both conditions. It is concluded that high-altitude natives do not display any sign of a greater sympathoadrenergic activation during chronic hypoxia and that the exercise-induced hormonal changes remained unaffected by acute inhalation of a normoxic gas mixture.
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PMID:Hormonal and metabolic adjustments during exercise in hypoxia or normoxia in highland natives. 892 8

In glycogen-depleted subjects (GD) a nonlinear increase in epinephrine (Epi) and norepinephrine (NE) parallels blood lactate (La) during graded exercise. The effect of glucose (Glc) supplementation and route of administration on these relationships was studied in 26 GD athletes who were randomly assigned to receive 1.3 g/kg Glc by slow intravenous infusion (IV; n = 9), oral administration (PO; n = 9), or artificially sweetened placebo in 1 liter of water (Asp; n = 8) in the 2 h preceding a graded maximal exercise. Performance and La were similar among the three groups in normal glycogen (NG) or GD conditions. However, slightly improved performances were observed in GD compared with NG and were associated with a shift to the right in La curves. Blood Glc concentrations were higher in IV and PO before exercise, but they rapidly decreased to lowest levels in IV, gradually decreased over time in PO, and remained stable in Asp or NG. Insulin concentrations were highest in IV and lowest in Asp and NG at onset of exercise, rapidly decreasing in IV and PO although remaining at higher levels than in Asp or NG. In contrast, higher serum levels of free fatty acids were measured during exercise in Asp with no significant differences in glucagon or glycerol among the three groups. Free and sulfated NE increases were smaller in IV than in PO and Asp on exhaustion. In contrast, free and conjugated Epi were most increased in IV, with smallest increases in Asp. Dopamine levels were most increased in IV at exhaustion. We conclude that the changes of Epi and NE concentrations, associated with the activation of glucoregulatory mechanisms, including hyperinsulinemia, display different magnitude and time courses during exercise in GD subjects who receive oral vs. intravenous load of Glc before exercise. We speculate that the magnitude of insulin surge after acutely increased Glc before exercise in GD subjects may exert dissociative effects on adrenal-dependent glycogenolysis and on sympathetic responses.
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PMID:Glucose administration before exercise modulates catecholaminergic responses in glycogen-depleted subjects. 902 23

We designed this study to determine whether the capacity of the liver to uptake ammonia and produce urea was affected by exercise (swimming at 24 degrees C with a 2.5% extra body-weight load). For this purpose, livers from sedentary rats at rest were perfused with a buffer containing increasing concentration of NH4Cl. The maximal hepatic capacity to produce urea was found at an NH4Cl concentration of 0.25 mM. Based on this finding all experiments with livers obtained from rats subject to swimming exercise were also carried out with a NH4Cl concentration of 0.25 mM. Thus, employing this concentration of ammonia, livers from sedentary and endurance trained rats, (for a period of 11 days ), that had either been resting or had been subjected to swimming exercise for 5 min or until exhaustion, were perfused in situ and ammonia uptake and urea production were measured. Clearly, both parameters were increased by exercise. However, these changes were not affected by swimming training. In addition, we demonstrate that the effect of an acute exercise on hepatic metabolism is not restricted to ammonia metabolism since livers from sedentary rats which had been subjected to swimming exercise for 5 min or until exhaustion showed higher urea production from L-glutamine. Our results also suggest that part of the changes in ureogenesis induced by exercise is mediated by cortisol (increased ammonia uptake) and part of the changes is mediated by glucagon (urea production).
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PMID:Swimming-exercise increases the capacity of perfused rat liver to produce urea from ammonia and L-glutamine. 1034 15

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