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)

A protein from porcine gut with 100 amino acid residues (porcine gut GLI-1) and having glucagon-like immunoreactivity has been characterized by partial sequences. The sequence of the C-terminal amino acid residues is -Met-Asn-Thr-Lys-Arg-Asn-Lys-Asn-Asn-Ile-Ala and includes the C-terminal amino acid residue sequence (-Met-Asn-Thr) of porcine glucagon. Evidence is presented that the glucagon sequence -Thr-Ser-Asp-Tyr-Ser-Lys-Tyr- is found in the gut GLI-1 as well. The data support the theory that gut GLI-1 contains the full glucagon sequence and that gut GLI-1 and glucagon are formed from a common precursor.
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PMID:Sequence analysis of porcine gut GLI-1. 88 77

Seven men ran at 60% of individual maximal oxygen uptake to exhaustion during beta-adrenergic blockade with propranolol (P), during lipolytic blockade with nicotinic acid (N), or without drugs (C). The total work times (83 +/- 9 (P), 122 +/- 8 (N), 166 +/- 10 (C) min, mean and SE) differed significantly. Epinephrine rose progressively above preexercise levels (0.06 +/- 0.01 ng/ml); at exhaustion concentrations in P experiments (2.15 +/- 0.41) were larger than in N (1.08 +/- 0.31) and C (0.72 +/- 0.28) experiments. Norepinephrine increased consistently while insulin decreased. After an initial decrease glucagon concentrations increased progressively in parallel with declining plasma glucose and were at exhaustion always three times preexercise values. Thus beta-adrenergic blockade did not diminish the glucagon response. Nor was this response increased when alpha-receptor stimulation in P experiments was intensified. Carbohydrate combustion was smaller and NEFA and glycerol concentrations in serum larger during C experiments. Alanine concentrations were never raised at exhaustion. Accordingly, neither stimulation of adrenergic receptors nor NEFA and alanine concentrations are major determinants for the exercise-induced glucagon secretion in man. It is suggested that decreased glucose availability enhances the secretion of glucagon and epinephrine during prolonged exercise.
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PMID:Glucagon and plasma catecholamines during beta-receptor blockade in exercising man. 93 21

Arterial blood concentrations of insulin, glucagon, and various substrates were determined in six anephric subjects in the postabsorptive state and immediately after hemodialysis. Plasma glucose and serum insulin concentrations were normal, and declined during dialysis. Plasma glucagon was elevated and remained unchanged. There was moderate hypertriglyceridemia before dialysis, but this decreased significantly after administration of heparin just before the start of dialysis, and at the end of dialysis was lowered further into the normal range. Comparison of postabsorptive whole blood concentrations of amino acids with those in normal, healthy adults revealed striking differences. Glutamine, proline, citrulline, glycine and both 1- and 3-methyl-histidines were increased, while serine, glutamate, tyrosine, lysine, and branched-chain amino acids were decreased. The glycine/serine ratio was elevated to 300% and tyrosine/phenylalanine ratio was lowered to 60% of normal. To investigate the potential role of blood cells in amino acid transport, the distribution of individual amino acids in plasma and blood cell compartments was studied. Despite a markedly diminished blood cell mass (mean hematocrit, 20.6 +/- 1.4%), there was no significant decrease in the fraction of most amino acids present in the cell compartment, and this was explained by increases of several amino acids in cellular water. None were decreased. Furthermore, during dialysis, whole blood and plasma amino acids declined by approximately 30% and 40%, respectively, whereas no significant change was observed in the cell compartment. Alanine was the only amino acid whose concentration declined in the cells as well as in plasma. The results indicate (a) significant alterations in the concentrations of hormones and substrates in patients on chronic, intermittent hemodialysis; (b) removal of amino acids during hemodialysis, predominantly from the plasma compartment, with no significant change in cell content; and (c) a redistribution of amino acids in plasma and blood cell compartments with increased gradients of most of the amino acids per unit cell water, by mechanism(s) as yet undetermined.
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PMID:Hormone-fuel concentrations in anephric subjects. Effect of hemodialysis (with special reference to amino acids). 93 88

1. Six well-trained cyclists and six untrained subjects were studied during and immediately after four successive 7 min periods of exercise at 30, 45, 60 and 75% of their maximal work capacity. 2. Venous blood samples were taken at rest, at the end of each exercise period and 5 min following the end of exercise, for estimation of metabolites in blood and plasma insulin, growth hormone, cortisol and catecholamines. 3. The results showed significant differences in the mobilization and utilization of muscle fuels between the athletically fit cyclists and the untrained group. In the cyclists, glucose, glycerol and free fatty acid concentrations were higher, but lactate, pyruvate and alanine were lower than in the untrained subjects during exercise. 4. Plasma catecholamines rose in both groups during exercise but the rise was significantly less in the racing cyclists. Plasma insulin was depressed to a greater extent in the untrained subjects during exercise and plasma glucagon rose to a greater extent during strenuous exercise and remained elevated after the end of exercise in the untrained group. Plasma human growth hormone rose to a greater extent during exercise and remained elevated after the end of exercise in the untrained group. Plasma cortisol fell at low and moderate exercise rates in both groups, but to a smaller extent in the cyclists. Cortisol values rose at higher workloads and were significantly higher in the cyclists at the end of exercise. 5. It is concluded that there are significant differences in the metabolic and hormonal responses to exercise between athletically trained and untrained individuals, even when the physically fit subjects work at the same percentage of their maximal capacity as the unfit subjects.
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PMID:Differences in the metabolic and hormonal response to exercise between racing cyclists and untrained individuals. 94 45

1. Isolated lamb liver cells were prepared from 24-h-starved animals by venous perfusion of the excised caudate lobe with buffer containing collagenase. On the basis of Trypan-Blue exclusion, rate of O2 uptake, adenine nucleotide content and retention of constitutive enzymes, these cells were judged to be intact. 2. Isolated caudate-lobe liver cells showed rates of gluconeogenesis from 10 mM-propionate and 10 mM-lactate that compared favourably with rates determined in isolated median-lobe cells and with rates determined with the isolated perfused lamb liver. 3. The gluconeogenic potential of substrates tested depended on the lamb's age. Cells prepared from suckling lambs (up to 20 days of age and essentially non-ruminant) showed highest rates from galactose, serine and alanine; those prepared from post-weaned lambs (older than 30 days of age and ruminant) showed highest rates from propionate, lactate and fructose. 4. Gluconeogenic rates from endogeneous precursors, 10 mM-propionate and 10mM-galactose, were linear for 1 h and were both stimulated by 1 muM-glucagon. Provided the endogenous rate of gluconeogenesis remained unchanged after substrate addition, glucagon caused a net stimulation of gluconeogenesis from each of these substrates. 5. Gluconeogenic capacity and glucagon sensitivity were examined in cells maintained in substrate-free oxygenated buffer at 37 degrees, 22 degrees and * degrees C. Even under the best of the three conditions of storage that were tested (i.e. at 22 degrees C in gelatin-containing buffer) deterioration of the lamb cells proceeded rapidly, and loss of glucagon responsiveness preceeded the loss of ability to convert precursor into glucose. 6. n-Butyric acid, 2-methylpropanoic acid and 3-methylbutanoic acid at concentrations comparable with those found in lamb portal-vein blood each stimulated gluconeogenesis from 10mM-galactose or 10mM-propionate; gluconeogenesis from galactose was stimulated to the greater extent. 7. The regulatory effects of glucagon and sodium butyrate on lamb liver-cell gluconeogenesis and glycogenolysis were compared. Glucagon (1 muM) and 2mM-butyrate accelerated the rate of glucose formation of liver cells of 24h-starved animals from lactate+pyruvate or fructose. Insulin (20nM) decreased both gluconeogenesis and the efficacy of 1 muM-glucagon. For lactate+pyruvate as substrate, the stimulatory effect of butyrate was additive to that of 1muM-glucagon and for both lactate+pyruvate and fructose the stimulatory effect of butyrate was not influenced by 20nM-insulin. In contrast with glucagon, which stimulated the rate of glycogenolysis in cells prepared from fed lambs, butyrate (0.1-20mM) had no effect. 8. It is concluded that glucagon and butyrate stimulate lamb liver-cell gluconeogenesis by different mechanisms.
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PMID:Gluconeogenesis in isolated intact lamb liver cells. Effects of glucagon and butyrate. 94 49

Hepatocytes were isolated from fed rats with glucose and insulin and freom fasted rats with glucagon in all media in an attempt to obtain cells which might be fixed preferentially in either the glycolytic or gluconeogenic state. When tested enzymatically, both "fed" and fasted" cells catalyzed glucose formation from lactate (gluconeogenesis) and lactate formation from fructose (fructolysis); lactate formation from glucose may have occurred in "fed" cells. Thus it was impossible, at least in the C3 part of the metabolic pathways between triosephosphate and pyruvate, to fix the hepatocytes in either metabolic state. The shift from glycolysis to gluconeogenesis could be investigated for the C3 part in "fasted" cells with fructose as the glycolytic and lactate as the gluconeogenic substrate. Lactate was first formed from fructose and later reutilized to a large extent. This reconsumption was blocked by the gluconeogenesis inhibitor quinolinate, both when tested enzymatically and radiochemically. Thus fructolysis was shifted to lactate gluconeogenesis. This shift at the assumed phosphoenolpyruvate/pyruvate cycle was autoregulatory, i.e. dependent on substrates and independent of circulating horomes. Maximal velocities and half saturating concentrations were determined for fructose and for lactate as substrates. The kinetic data obtained, especially the sigmoidal pattern of fructolysis, could nicely explain phenomenologically the rather sudden slow-down of lactate production and the shift to lactate consumption. The levels of the metabolites ATP, ADP, AMP, fructose bisphosphate and alanine, which control the enzymes of the assumed phosphoenolypyruvate/pyruvate cycle, were determined in the cytosol and in the mitochondria before and after the shift from fructose glycolysis to lactate gluconeogenesis. The changes observed could not explain the shift. Experiments with [14C] fructose plus unlabelled lactate and reciprocally, with unlabelled fructose plus [14C] lactate, clearly reveled that within the C3 part, glycolysis and gluconeogenesis were catalyzed simultaneously. The simultaneity of and the shift between fructolysis and gluconeogenesis by the liver cell suspension can best be explained by assuming two metabolically different types of hepatocytes rather than one type of hepatocyte with metabolically equal or different cell compartment. In vivo, the different types of hepatocytes would form a gluconeogenic and a glycolytic zone within the liver parenchyma. Since, under normal conditions, the size of these metabolic zones should remain unaltered, the shift from net glycolysis to net gluconeogenesis would be dependent primarily on substrate concentrations (autoregulation).
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PMID:Autoregulatory shift from fructolysis to lactate gluconeogenisis in rat hepatocyte suspensions. The problem of metabolic zonation of liver parenchyma. 95 64

Human liver tissue was obtained as surgical biopsies in 29 subjects operated on for uncomplicated gallstone disease. Liver slices were incubated in Krebs-Ringer bicarbonate buffer solution, pH 7.4, with 17 l-amino acids, lactate, glycerol, and glucose at various concentrations. The incorporation rate of alanine, lactate, and glycerol into glucose, glycogen, and CO2 was determined by use of 14C-labeled precursors. The gluconeogenetic rate of all substrates was increased 10-35 times by increasing precursor concentration in the medium. Insulin at a physiological concentration (300 mU/l) and dexamethasone (0.001 mmol/l) had slight but significant effects on the incorporation rate of alanine into glucose and glycogen, respectively. Glucagon had no effect. Glucose in the incubation medium did not influence the incorporation rate of precursors into glucose, glycogen, or CO2, suggesting that glucose was not of importance for the regulation of the gluconeogenesis. The gluconeogenetic rate of a precursor was not dependent on or influenced by the presence of other precursors. The gluconeogenesis in human liver slices at physiological concentrations of precursors was 5-20% of the maximal rate reported for the rat liver. When the precursor concentration in the medium was increased, the gluconeogenetic rate increased to values close to those reported for the rat liver in vitro and for man in vivo. This in vitro preparation of human liver seems to be valid for evaluation of gluconeogenesis in man.
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PMID:Gluconeogenesis in human liver tissue. An in vitro method for evaluation of glyconeogenesis in man. 95 52

Forty-eight male rats were fed a nutritionally complete diet containing 30% of dietary energy as fat. For 24 animals (control) the fat source was corn oil, for the remaining 24 rats (experimental) the fat source was a triundecanoin-corn oil mixture (7:3, wt/wt). After 6 wk, groups of control and experimental rats were killed after 0, 24, and 48 h of fasting. In the experimental group, adipose tissue fatty acids contained, on average, 280 mmol undecanoate/mol fatty acid. In the control group, no odd-numbered fatty acids were present. During fasting, the experimental groups had higher plasma glucose and alanine levels, higher plasma insulin-to-glucagon ration, and lower liver phosphenol pyruvate caboxykinase. The results suggest that the terminal propionate residues generated when odd carbon fatty acids are oxidized become gluconeogenic precursors and cause a reduced need for gluconeogenesis from protein.
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PMID:Glucagon, insulin, and gluconeogenesis in fasted odd carbon fatty acid-enriched rats. 96 87

The present study examines the role of insulin, glucagon and cortisol in the regulation of gluconeogenesis from lactate and amino acids in fetal and newborn rats. Injection of glucagon in the full-term fetal rat caused a rise in glucose (and insulin) and a fall in blood levels of most individual amino acids, stimulated hepatic accumulation of 14C-amino isobutyric acid and 14C-cycloleucine and increased the conversion of 14C lactate, alanine and serine to glucose in vivo and in vitro (liver slices). Such changes were equivalent to the changes seen in 4 h old newborn rats. When glucagon was administered at birth, little difference was observed between control and treated animals in plasma amino acids and a smaller increment in conversion of 14C substrate to glucose occurred. By contrast, insulin injection at birth caused hypoglycemia, suppression of levels of certain amino acids and inhibition of conversion of 14C substrates into glucose. Glucose injection at birth caused elevated glycemia and plasma insulin and suppression of most amino acid levels and of conversion of 14C substrate into glucose. Cortisol injection at birth caused a marked, generalized by hyperaminoacidemia, a stimulation of glucagon secretion and of conversion of 14C substrates into glucose. These observations support the thesis that glucagon plays a major role in the induction of hepatic gluconeogenesis and that insulin acts as an antagonist hormone.
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PMID:Effects of exogenous hormones and glucose on plasma levels and hepatic metabolism of amino acids in the fetus and in the newborn rat. 96 9

A protein with glucagon-like immunoreactivity has been isolated from porcine intestine in a highly purified form. The isoelectric point is 6.8-6.9, and the molecular weight is 11,625, as calculated from its amino acid composition: this estimate has been confirmed by S.D.S. gel electrophoresis. The partial sequence so far elucidated is from the N-terminal: Arg-Ser-Leu-Gin-Asn-Thr-Glx-Glx-Lys-Ala-Arg-Ser-Phe-, and from the C-terminal: -Ile-Ala, both differing from those of porcine pancreatic glucagon. On a molar basis the protein has the same immunoreactivity as porcine glucagon when assayed with some anti-glucagon sera, while the activity is less than 0.2% using other anti-glucagon sera.
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PMID:Purification and characterization of a protein from porcine gut with glucagon-like immunoreactivity. 97 35


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