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)

Fasting concentrations, clearance of exogenous infused amino acids, and lean body mass were studied in a patient with glucagonoma syndrome (fasting glucagon = 380 pmol/l, normal range 15-45 pmol). The fasting concentrations of all amino acids were reduced. The clearances of alanine, arginine, glycine, isoleucine, leucine, lysine, methionine, proline, serine, threonine, and tyrosine were increased. The urea synthesis rate during amino acid infusion was 27 mumols/kg per minute (normal range 20-24 mumols/kg per minute). The lean body mass of the patients was reduced to 59% of the expected value. It is suggested that the weight loss of patients with glucagonoma syndrome is partly due to increased hepatic conversion of amino acid nitrogen to urea nitrogen, resulting in decreased blood amino acid concentration, and secondary to this, organ protein catabolism, as shown by the decreased lean body mass.
 ...
PMID:Increased amino acid clearance and urea synthesis in a patient with glucagonoma. 216 78

Arginine vasotocin (AVT) and isotocin (IT) induced direct inhibition of adenylate cyclase activity in gill plasma membranes of the rainbow trout adapted to freshwater (FW) and seawater (SW). The maximal inhibition was obtained with 10(-11)-10(-10) M (50% inhibitory concentration approximately 10(-13) M), values in agreement with the circulating levels of AVT in trout blood. Specific V1 or V2 agonists or antagonists (with reference to vasopressin) were used to define the specificity of the neurohypophysial peptide receptors involved in this inhibition. The V1 agonist [Phe2,Orn8]vasotocin ([Phe2]OVT) inhibited the basal and glucagon-stimulated adenylate cyclase activity, and this effect in SW (20%) was twice more than in FW (10%). The V2 agonist 1-deamino[Val4,Arg8]-vasopressin (dVDAVP), however, produced a stimulation that was of the same amplitude (10%) in both media. The V1 antagonist [(1-beta-mercapto-beta-beta-cyclopentamethylenepropionic acid), 1-(O-ethyl)Tyr2,Orn8]vasotocin (d(CH2)5[Tyr(Et)2]OVT) totally reversed the AVT- or IT-induced inhibition of basal or glucagon-stimulated cyclase activity, whereas the V1/V2 antagonist [(1-beta-mercapto-beta-beta-cyclopentamethylene propionic acid), 1-(O-ethyl)D-Tyr2,Val4,Arg8]vasopressin (d(CH2)5[D-Tyr(Et)2]-VAVP) (previously used as V2 antagonist in amphibians) had no such effect. When active, all analogues had their maximal activity at 10(-11)-10(-10) M (50% maximal activity approximately 10(-13) M), as observed with the natural peptides. These results, together with our previous observations, point to the gill epithelium as a direct target organ for neurohypophysial peptides and suggest that the hormone receptors involved in fish belong predominantly, if not exclusively, to a new type that we propose to designate as fish neurohypophysial hormone (NHF) receptors while awaiting further characterization.
 ...
PMID:Evidence for presence of a new type of neurohypophysial hormone receptor in fish gill epithelium. 230 44

Increased plasma levels of the catabolic hormones glucagon, epinephrine, and cortisol have been implicated in mediating various metabolic alterations in trauma and sepsis. Their role in altered protein turnover and amino acid transport in skeletal muscle during sepsis, however, is not known. In the current study, rats were infused with a mixture of the catabolic hormones for 16 hours. Control animals were infused with vehicle solution. Protein synthesis and degradation rates were measured in incubated, intact soleus muscles as incorporation of 14C-phenylalanine into protein and release of tyrosine into incubation medium, respectively. Muscle amino acid uptake was determined by measuring the intracellular to extracellular ratio of [3H]-alpha-aminoisobutyric acid after incubation for 2 hours. Infusion of catabolic hormones for 16 hours resulted in elevated plasma glucose and lactate levels, reduced plasma concentrations of most amino acids, and accelerated muscle protein breakdown, similar to previous findings in septic rats. Protein synthesis rates and amino acid uptake in incubated muscles were not significantly different in control and hormone-infused rats. The current study suggests that increased muscle proteolysis in sepsis and severe injury may be mediated in part by catabolic hormones. In contrast, reduced muscle protein synthesis and amino acid uptake are probably signaled by other substances or mechanisms.
 ...
PMID:Effect of catabolic hormone infusion on protein turnover and amino acid uptake in skeletal muscle. 230 36

At physiological pH and temperature, glucagon binds to liposomes composed of egg phosphatidylcholine and cholesterol (2:1 mol/mol) in a highly specific manner. The chemical reactivities of the functional groups were determined over the concentration range of 1.0 X 10(-6)-3.0 X 10(-8) M by the method of competitive labelling with 1-fluoro-2,4-dinitrobenzene as the labelling reagent. At concentrations above 3 X 10(-7) M, the amino terminal histidine and the two tyrosine residues showed a marked decrease in reactivity in the presence of liposomes, but the reactivity of the Lys-12 N epsilon-amino group was unaltered. At lower concentrations the Lys-12 reactivity also decreased markedly, owing to a change in the environment of this group. These results indicated that two different forms of glucagon existed over the concentration range studied. Both in the absence and presence of liposomes the Lys-12 N epsilon-amino groups showed a transition in reactivity at 1.8 X 10(-7) M. In the presence of liposomes the other functional groups also showed a transition in reactivity at 2 X 10(-7) M but the change was much smaller. The pattern of reactivities were consistent with the X-ray crystallographic structure of the type 2 glucagon trimer being the predominant species at 10(-6) M, with free monomeric glucagon occurring at 3 X 10(-8) M. A trimerization constant of 4 X 10(13) M-2 at pH 7.5 and 37 degrees C was determined.(ABSTRACT TRUNCATED AT 250 WORDS)
 ...
PMID:Binding of glucagon to lipid bilayers. 235 Apr 93

In order to characterize the differentiation of endocrine cells present in Barrett's oesophagus and to determine if they express a single or multiple hormonal pattern, endoscopic biopsies were taken from both the lesion and the fundus of 45 patients and studied at the light microscopical level. Conventional histology revealed three different epithelial patterns: gastric atrophic fundic, intestinal and junctional. A mixture of these patterns was present in 28 cases (62%) and the single type was identified in 17 cases (38%). The use of three silver staining methods and antibodies to human chromogranins allowed us to identify numerous endocrine cells in all but 1 case. Eleven sera against all the most common hormones stored in the endocrine cells of the gut were used to identify the main products of the cells. The following immunoreactivities were identified: 5-hydroxytryptamine (5-HT) (in 75% of the studied cases), somatostatin (87%), motilin (31%), pancreatic polypeptide (PP) (20%), glucose-dependent insulinotropic polypeptide (20%), gastrin (15%), glucagon (15%), peptide tyrosine tyrosine (13%), secretin (7%) and neurotensin (2%). No cholecystokinin-immunoreactive cells were identified. Our results indicated that, in Barrett's epithelium, both gastric and intestinal endocrine cells differentiate, in accordance with the variability of differentiation in the non-endocrine cells present in the different types of columnar epithelium. These findings provide support for the conclusion that Barrett's epithelium arises from a pluripotential stem cell capable of both gastric and intestinal differentiation.
 ...
PMID:A mixed pattern of endocrine cells in metaplastic Barrett's oesophagus. Evidence that the epithelium derives from a pluripotential stem cell. 244 38

Galanin was infused intravenously in 8 healthy volunteers at a dose of 40 pmol/kg.min for 1 h to investigate the pharmacologic effects of this peptide on postprandial gastrointestinal motility and gut peptide release in humans. Galanin strongly inhibited gastrointestinal motility. Gastric emptying was significantly delayed, with the time taken to empty 50% of the gastric contents increasing from 59.0 +/- 4.8 min (control infusion) to 99.3 +/- 4.7 min (galanin infusion). Mouth-to-cecum transit time increased from 67.5 +/- 6.9 to 126.3 +/- 18.5 min. Galanin potently suppressed the initial postprandial rise in plasma concentrations of glucose, insulin, peptide tyrosine tyrosine, neurotensin, enteroglucagon, pancreatic glucagon, somatostatin, and pancreatic polypeptide, but did not change gastric inhibitory polypeptide, motilin, peptide histidine methionine, and gastrin concentrations compared with control. The results indicate that an infusion of galanin has potent effects on the gastrointestinal tract in humans. The changes in motor activity in particular suggest that the local galaninergic innervation could have an important physiologic role in the control of human gastrointestinal propulsive motor activity.
 ...
PMID:Inhibitory effect of galanin on postprandial gastrointestinal motility and gut hormone release in humans. 247 97

Galanin, a 29 amino acid peptide, inhibits insulin and somatostatin secretion from the isolated, perfused dog pancreas. To assess the nature of the influences of galanin on the endocrine pancreas, we examined the effects of porcine galanin and six different galanin analogues at the equimolar concentration of 1 nmol/l on the hormone release from the isolated, perfused dog pancreas. It was found that galanin2-29 (by 75 +/- 4%), like the native galanin1-29 (by 90 +/- 3%) potently inhibited insulin secretion (p less than 0.001). In contrast, galanin3-29 did not significantly affect insulin secretion. This indicates that removal of the two N-terminal amino acids markedly reduces the potency of galanin. Also, the replacement of the amino acid number 2 (Trp) by Tyr or Phe was followed by a loss of the insulin lowering effect of galanin at this dose level. Likewise, galanin10-29 had no significant effect on insulin secretion. In contrast, the C-terminally deleted galanin1-15 significantly inhibited insulin secretion (by 24 +/- 5%; p less than 0.01), though with a lower potency than did native galanin (p less than 0.05). Consequently, the C-terminal end of galanin is also of importance for the effect. Somatostatin secretion was inhibited by galanin (p less than 0.001), but not by any of the other investigated peptides. Glucagon secretion was not affected by galanin. It is concluded that the two N-terminal amino acids of galanin are essential for the inhibitory action on the insulin secretion.(ABSTRACT TRUNCATED AT 250 WORDS)
 ...
PMID:On the nature of the galanin action on the endocrine pancreas: studies with six galanin fragments in the perfused dog pancreas. 247 81

The ontogeny of oxytocin receptors in rat forebrain was studied using the selective oxytocin receptor antagonist 125I-d(CH2)5[Tyr(Me)2, Thr4, Tyr-NH29]OVT [( 125I]-OTA). With in vitro receptor autoradiography, binding wa noted on the first postnatal day in dorsal subiculum and thalamus. On postnatal days 5-18, intense labeling was evident in posterior cingulate cortex, dorsal subiculum, lateral septum, and the CA1 subfield of hippocampus. Of these regions only the lateral septum expressed oxytocin receptors in adult brain. Competition studies on coronal sections through posterior cingulate, septum, and dorsal subiculum at P10 demonstrated that transient binding sites in these areas were indeed oxytocin selective (OXY greater than AVP greater tha V1 greater than V2). Result of saturation studies on cingulate membranes from 10-day-old pups agreed favorably with previous reports of the kinetics of [125I]-OTA binding to adult oxytocin receptors (Kd = 0.1 nM in P10 cingulate cortex vs. 0.07 nM for adult ventral subiculum). In contrast to these evanescent developmental sites, oxytocin receptors in the bed nucleus of the stria terminalis and the ventromedial nucleus of the hypothalamus only appeared in adulthood, presumably in response to the surge of gonadal steroids at puberty.
 ...
PMID:Ontogeny of oxytocin receptors in rat forebrain: a quantitative study. 255 21

To determine the effect in normal subjects of small variations of insulin and glucagon on plasma aminoacids concentrations we suppressed endocrine pancreas secretion with somatostatin and measured aminoacids levels during a sequential insulin infusion in the absence (control test, low glucagon level) or in the presence (normal glucagon concentration) of a replacement glucagon infusion. Insulin infusion rates were 0.05, 0.09, 0.15 and 0.30 mU.kg-1.min-1 during the control test and 0.09, 0.15, 0.30 and 0.40 mU.kg-1.min-1 during the replacement test. During the control test, glucagon decreased (p less than 0.01) and insulin levels were successively 8.2 +/- 0.4, 10.1 +/- 0.7, 11.9 +/- 0.14 and 18.5 +/- 0.8 mU.l-1. The only effect on insulin was to decrease branched-chain aminoacids (BCAA). BCAA were inversely related to insulinemia (p less than 0.01). A significant decrease was obtained for an insulin level of 11.9 +/- 0.4 mU.l-1, a value intermediate between those decreasing glycerol (10.1 +/- 0.7 mU.l-1) and stimulating total body glucose uptake (18.5 +/- 0.8 mU.l-1). During the test with glucagon replacement glucagon was maintained at its initial value. Insulin levels were successively 8.3 +/- 0.3, 11.9 +/- 0.3, 19.7 +/- 0.6 and 26.7 +/- 0.5 mU.l-1. Insulin decreased always BCAA but also threonine, proline, tyrosine, methionine and total aminoacid levels. BCAA were always inversely related to insulin levels (p less than 0.01) but the slope of the relationship was modified and more insulin was needed to decrease BCAA concentration.(ABSTRACT TRUNCATED AT 250 WORDS)
 ...
PMID:Effects of small variations in insulin and glucagon levels on plasma aminoacids concentrations. 256 20

The pathways by which islet B, A, and D cells bind and internalize homologous (self) and heterologous (other) islet hormones were compared. [125I-Tyr]Somatostatin-14 (S-14), 125I-insulin, and 125I-glucagon were incubated with monolayer cultures of neonatal rat islet cells. Tissues were processed for quantitative electron microscopic autoradiography by the probability circle method coupled to morphometry. For all three radioligands and all three cell types surface labeling was rapidly followed by internalization of the radioligands into endocytotic vesicles. The further intracellular movement of the ligand occurred in a time- and temperature-related manner and depended on whether it was homologous or heterologous for the cell in question. Thus [125I-Tyr]S-14 in B and A cells, 125I-insulin in A and D cells, and 125I-glucagon in B and D cells were rapidly transferred from endocytotic vesicles to lysosomal structures. By contrast, [125I-Tyr]S-14 in D cells, 125I-insulin in B cells, and 125I-glucagon in A cells showed poor progression from endocytotic vesicles to downstream vesicular structures. We conclude that (a) each of the three radioligands is internalized by islet cells in a time- and temperature-dependent manner; (b) after initial internalization the further intracellular progression of the endocytosed radioligand occurs freely in cells heterologous for the radioligand but poorly in cells homologous for the radioligand; and (c) binding and endocytosis can be uncoupled from lysosomal degradation of ligand.
 ...
PMID:Binding and internalization of somatostatin, insulin, and glucagon by cultured rat islet cells. 256 74


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