Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UNIPROT:P01275 (glucagon)
 26,492 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Lipid metabolism was studied in experimental uremia. Uremic (U) rats were compared with sham-operated, pair-fed (PF) controls and with ad-lib-fed (AL) controls. In U animals, fasting glucose concentrations were normal, immunoreactive serum insulin (IRI) levels were decreased, and immunoreactive glucagon levels were increased. A significant increase in the serum concentration of all lipid classes was observed: triglycerides were elevated 10-fold above the values in PF and AL controls; phospholipids, twofold; total cholesterol, threefold; and free cholesterol, sixfold. Cholesterol concentration was increased in beta- and pre-beta-lipoproteins and even more so in alpha- and pre-alpha-lipoproteins. There was an increase in the ratio of free cholesterol/total cholesterol. The fatty acid composition of serum lipoproteins was unchanged. Concomitantly, in liver tissue, there was no change in lipid content (triglyceride, cholesterol) and fatty acid composition. These findings argue against glucose- or insulin-mediated changes in hepatic de novo fatty acid synthesis, chain elongation, or poly-desaturation. In U animals, the HMG-CoA-reductase activity of liver microsomes was slightly, but not significantly, reduced as was tritiated water incorporation into cholesterol in isolated perfused liver preparations. In adipose tissue, there was a decrease in triglyceride content. The results provide evidence against insulin-mediated hepatic overproduction as a major cause of hyperlipoproteinemia in this model of experimental renal insufficiency and point to peripheral under-utilization of lipoproteins.
 ...
PMID:Hyperlipoproteinemia in experimental chronic renal insufficiency in the rat. 69 73

The effects of glucagon, gastric inhibitory peptide (GIP), and secretin on the concentrating mechanism and the motility in the feline gallbladder have been studied in vivo. A technique by which the gallbladder in situ was perfused by an electrolyte solution made possible a simultaneous study of the motility and of the net transport of water and electrolytes across the gallbladder wall. Secretin (0.6 microgram per kg/h) was found to abolish the net absorption of water, Na+, and HCO3- and strongly reduce the net absorption of K+ and Cl-, whereas neither glucagon (1--20 microgram per kg/h) nor GIP (1--30 microgram per kg/h) was found to significantly influence the concentrating function of the gallbladder. The motility of the gallbladder was not influenced by the peptides. The formation of bile and pancreatic secretion was not changed by glucagon or GIP, whereas secretin had a potent effect.
 ...
PMID:A comparison of glucagon, gastric inhibitory peptide, and secretin on gallbladder function, formation of bile, and pancreatic secretion in the cat. 72 15

The response of 13 pigs to total pancreatectomy was compared with the response of 9 animals to sham operation. Approximately half of each group had free access to food while the remainder received oral water only. Completeness of pancreatectomy was confirmed at autopsy, and the disappearance of insulin and the rise in blood glucose to 14-19 mmol/l. Immunoreactive glucagon (IRG) increased in fed pancreatectomized pigs from the 3rd day postoperatively to a level of 350-400% of basal values by the 8th day. There was no rise in starved pancreatectomized animals, or in either group of sham-operated animals. The rises in glucose, free fatty acids, triglycerides and ketones were similar in the two groups of pigs.
 ...
PMID:The effect of feeding and starvation upon immunoreactive glucagon in the pancreatectomized pig. 74 86

Intramuscular administration of crystalline mammalian glucagon (0.5-2.0 mg/kg body weight) evokes significant cytological alterations in the principal islets of Channa punctatus, a fresh-water fish. Initially there is degeneration of the alpha-cells but later the beta-cells are also atrophied. Regressive changes in some of the alpha-cells have been interpreted to reflect their possible role in glucagon secretion. The degeneration of beta-cells appears to be secondary to the fluctuations in the blood glucose level, induced by exogenous glucagon.
 ...
PMID:Effect of glucagon on the principal islets of a fresh-water fish, Channa punctatus (Bloch). 78 39

1. Glucagon (0-05 or 0-5 microng/kg. min) was infused into a mesenteric artery of a canine ileal segment from which transport was measured (direct infusion) or into a mesenteric artery of an adjacent non-perfused segment (indirect infusion). Unidirectional Na and H2O fluxes and arterial and mesenteric vein pressures and total and absorptive site blood flows were measured. 2. Direct glucagon infusion increased the absorptive and secretory fluxes of Na and H2O and absorptive site blood flow, and decreased absorptive site resistance and arterial and mesenteric vein pressure. Indirect glucagon infusion had the opposite effects. 3. Neither the direct arterial infusion of histamine (0-1-53 microng/kg. min) nor the I.V. infusion of glucose (0-2 g/min) or insulin (0-1 micron/kg) or glucose plus insulin, mimicked the effects of glucagon. 4. The unidirectional secretory and absorptive fluxes of both Na and H2O were linearly related to the calculated capillary pressure during glucagon infusion. 5. It was concluded that the effects of glucagon on gut transport were due to effects exerted through the cardiovascular system.
 ...
PMID:Effects of glucagon on canine intestinal sodium and water fluxes and regional blood flow. 85 93

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.
 ...
PMID:Hormone-fuel concentrations in anephric subjects. Effect of hemodialysis (with special reference to amino acids). 93 88

Unidirectional K+ fluxes were measured in suspensions of isolated rat liver parenchymal cells incubated with 42K+ in vitro. By tracer exchange analysis fluxes in both directions were estimated to 8-9 10(-12) mol/cm2. Glucagon in concentrations above 2 x 10(-8) M increased both influx and efflux to 160% of control values. Insulin increased influx by 12-14%, whereas efflux was apparently unaffected. Using an extracellular marker 51Cr EDTA, intracellular level of some ions was estimated in isolated liver cells: K+ = 172 mmol/kg water, Na+ = 25 mmol/kg water, Cl = 53 mmol/kg water. Cellular water content: 60%. Incubation with insulin for 1 h increased the intracellular concentration of K+ 1.7 mmol/kg water. The results indicate that glucoagon increased primarily the K+-permeability of the cell membrane, while insulin stimulates active K+ transport into the cell.
 ...
PMID:K+ transport in isolated rat liver cells stimulated by glucagon and insulin in vitro. 94 6

Intragastric pressure was measured in dogs with gastric fistulas by using a flaccid balloon containing 500 ml of water. Intravenous infusion of cholecystokinin (20% pure), the carboxyl-terminal octapeptide of cholecystokinin, secretin, and vasoactive intestinal peptide produced dose-related decreases in intragastric pressure with maximal decreases of 40% or more. Glucagon and gastric inhibitory peptide produced smaller decreases in intragastric pressure. Motilin caused a dose-related increase in intragastric pressure that lasted only about 7 min despite continuing infusion of the peptide. The half-dose of cholecystokinin or of octapeptide of cholecystokinin for pancreatic protein secretion and the half-dose of secretin for pancreatic bicarbonate secretion each produced significant inhibition of intragastric pressure, suggesting that these hormones play a physiological reole in regulating gastric pressure.
 ...
PMID:Effect of intestinal hormones and peptides on intragastric pressure in dogs. 96 68

Endogeneous hyperglucagonemia is observed in experimental diabetes mellitus and semistarvation, conditions associated with an increased intestinal absorptive function. To examine whether glucagon might exert a similar adaptive response on intestinal digestive-absorptive function like experimental diabetes mellitus the effect of chronic glucagon administration on intestinal transport of 3-0-methyl-D-glucose, water, sodium, potassium, and D-glucose induced transmural potential difference (PD) was examined by an in vivo perfusion technique in rat small intestine. Chronic administration of glucagon (100 mug twice daily) for 5 days resulted in increased absorption of 3-0-methyl-D-glucose, water, sodium and potassium as well as in an increase of D-glucose induced PD. A similar, but more pronounced augmentation of D-glucose induced PD was observed in the jejunum of streptozotocin-diabetic rats. Disaccharidase (maltase, sucrase, trehalase, lactase) and alkaline phosphatase activities were not affected in intestinal mucosa of glucagon-treated rats compared to controls. It cannot be decided from these results whether hyperglucagonemia is responsible for the adaptive intestinal changes observed in experimental diabetes mellitus.
 ...
PMID:Effect of chronic glucagon-administration on the digestive and absorptive function of rat small intestine in vivo. 98 1

Tumoral secretions and pathophysiology of diarrhea were studied in 1 patient with pancreatic cholera. High concentrations of vasoactive intestinal peptide were found in both systemic blood and tumoral extracts, together with increased plasma levels of calcitonin and protaglandins E and Falpha. Gastric inhibitory peptide and gastrointestinal and pancreatic hormones were absent from the tumor, except for small amounts of glucagon, and their blood levels were normal. Decreased basal but normal pentagastrin-stimulated gastric acid secretion, normal basal and secretin-stimulated pancreatic secretion, increased volume of gallbladder bile with high bicarbonate, and low bile salt concentrations were observed, but the electrolyte content and flow rate of fluid passing the duodenojejunal junction were within normal limits. Small intestine was found to be the origin of the water and electrolyte fasting losses. Jejunum was the site of bicarbonate secretion. Jejunal glucose and leucine-stimulated water and sodium transports were also strikingly decreased, whereas the absorption rates of the sugar and amino acid were normal. Colon reabsorbed high amounts of water and sodium but increased potassium losses. Biological effects of vasoactive intestinal peptide may explain most of the patient's upper digestive secretion abnormalities and small intestinal function impairments, whereas secondary aldosteronism might explain the modified colonic function.
 ...
PMID:Pancreatic cholera. Sudies on tumoral secretions and pathophysiology of diarrhea. 109 88


<< Previous 1 2 3 4 5 6 7 8 9 10 Next >>