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 microassay was developed to measure the binding of the labelled monoiodinated analogue [1-(beta-mercapto-beta,beta-cyclopentamethylenepropionic acid), 2-O-methyltyrosine, 4-threonine, 8-ornithine, 9-125I-tyrosylamide]vasotocin [125I-d(CH2)5[Tyr (Me)2, Thr4, Tyr-NH(2)9]OVT] to isolated nephron segments microdissected from collagenase-treated rat kidneys. When determined using 1.7 nM labelled ligand at 4 degrees C, specific binding sites (expressed at 10(-18) mol 125I-d(CH2)5[Tyr (Me)2, Thr4, Tyr-NH(2)9]OVT bound/mm tubule length) were found in medullary thick ascending limbs (MTAL), 1.67 +/- 0.49; cortical thick ascending limbs, 2.20 +/- 0.80; cortical collecting ducts, 2.39 +/- 0.86; outer medullary collecting ducts (OMCD), 2.54 +/- 0.53 and inner medullary collecting ducts, 5.33 +/- 0.40, whereas no specific binding could be detected in glomeruli and proximal tubules. Specific 125I-d(CH2)5[Tyr (Me)2, Thr4, Tyr-NH(2)9]OVT binding to OMCD was saturable with incubation time and reversible after elimination of free labelled ligand (the association and dissociation rate constants at 4 degrees C were 1.06 x 10(7) M-1 min-1 and 1.95 x 10(-2) min-1 respectively). The stereospecificity of MTAL and OMCD binding sites was assessed in competitive experiments revealing the following recognition pattern for a series of eight vasopressin analogues:dDAVP greater than AVP greater than d(CH2)5-[Tyr (Me)2, Thr4, Tyr-NH(2)9]OVT = AVT = OT greater than d(CH2)5[Tyr(Me)2]AVP = [Thr4, Gly7]OT greater than [Phe2, Orn8]VT, whereas pharmacological concentrations of insulin and glucagon did not impair radioligand binding. These results indicate that the detected labelled binding sites might correspond mainly to physiological V2 vasopressin receptors.
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PMID:Receptors for neurohypophyseal hormones along the rat nephron: 125I-labelled d(CH2)5[Tyr(Me)2, Thr4, Orn8, Tyr-NH(2)9] vasotocin binding in microdissected tubules. 183 Mar 90

The absolute rates of hormone synthesis and release were determined in purified pancreatic B cells. Newly synthesized proteins were labeled with L-[3,5-3H]tyrosine or L-[2,5-3H]histidine. When medium glucose was less than or equal to 10 mM, the production of insulin exceeded or equaled its release. Raising the glucose levels above 10 mM did not further increase the rate of insulin synthesis (67 +/- 10 fmol/10(3) cells/2 hour) but elevated that of insulin release up to 3-fold the production rates (181 +/- 10 fmol/10(3) cells/2 hour). In the presence of glucagon or of the phorbol ester 12-O-tetradecanoylphorbol 13-acetate the cells also released 3-fold more hormone that they synthesized; release was however reduced to 25% of the rate of production in the presence of epinephrine. It is concluded that glucose as well as hormonal regulators of islet B cells can influence, bi-directionally, the balance between the rates of insulin synthesis and release.
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PMID:Measuring the balance between insulin synthesis and insulin release. 187 37

The effects of glucagon deficiency and excess on plasma leucine, lysine, and alanine were examined in six healthy young adult men, with primed continuous infusions of L-[1-13C]- or L-[5,5,5-2H3]leucine, L-[alpha-15N]-lysine, and L-[3-13C]alanine for 150 min before and during 210 min of either a glucagon-deficient euglycemic state (experiment 1), a basal glucagon state (experiment 2), or a glucagon-excess state (experiment 3). Steady-state plasma hormone levels were achieved by infusion of somatostatin (250 micrograms/h) and insulin (0.07 mU.kg-1.min-1), without (experiment 1) or with an infusion of glucagon at 0.7 ng.kg-1.min-1 (experiment 2) or 2.5 ng.kg-1.min-1 (experiment 3). Plasma branched-chain amino acid (AA) concentrations did not change with altered glucagon status, whereas significant differences were observed for plasma lysine, alanine, glycine, serine, threonine, proline, tyrosine, citrulline, and ornithine levels (0.05 greater than P greater than 0.001). Plasma leucine, lysine, and alanine fluxes and the rate of de novo alanine synthesis showed no significant changes with either glucagon deficiency or excess. These findings lead to the conclusion that glucagon-induced alterations in plasma AA profiles are not due to changes in the rate of appearance of AA from peripheral tissues but rather a consequence of changes in the fate of AA within the splanchnic region.
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PMID:Plasma amino acid kinetics during acute states of glucagon deficiency and excess in healthy adults. 196 9

The characteristics of somatostatin (SRIF) receptors in rat pancreatic beta-cells were investigated using rat islets and the beta-cell line HIT-T15 (HIT). The biochemical properties of the SRIF receptors were examined with 125I-labeled des-Ala-1,Gly-2-desamino-Cys-3-[Tyr-11]- dicarba3,14-somatostatin (CGP 23996). 125I-CGP 23996 bound to SRIF receptors in HIT cells with high affinity and in a saturable manner. The binding of 125I-CGP 23996 to SRIF receptors was blocked by SRIF analogues with a rank order of potency of somatostatin 28 (SRIF-28) greater than D-Trp-8-somatostatin greater than somatostatin 14 (SRIF-14). To investigate the physical properties of the HIT cell SRIF receptor, the receptor was covalently labeled with 125I-CGP 23996 using photo-cross-linking techniques. 125I-CGP 23996 specifically labeled a protein of 55 kDa in HIT cell membranes. The size of the SRIF receptor in HIT cells is similar to the size of the SRIF receptor labeled with 125I-CGP 23996 in membranes of freshly isolated islets, suggesting that the physical properties of SRIF receptors in HIT cells and rat islet cells are similar. The binding studies suggest that beta-cells predominantly express a SRIF-28-preferring receptor. In freshly isolated islets, glucose- and arginine-stimulated insulin release was effectively blocked by SRIF-28 but not by SRIF-14. SRIF-14 did inhibit arginine-stimulated glucagon secretion from freshly isolated islets. The dissociation of the inhibitory effects of SRIF-28 and SRIF-14 on insulin and glucagon release from freshly isolated islets suggests that the two peptides act through different receptors in islets to regulate hormone secretion.
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PMID:Pancreatic beta-cell somatostatin receptors. 197 86

The photochemically induced dynamic-nuclear-polarization (photo-CIDNP) NMR technique was used to investigate the membrane-active peptides melittin and glucagon. The experiments were performed both in the absence and presence of phospholipid vesicles in order to study the topography of the membrane-bound state. From the results it can be concluded that the melittin peptide chain is oriented in such a way that the single tryptophan residue (Trp19) reaches into the membrane. In the case of glucagon, a binding interaction with vesicle membranes is indicated within the pH range 2-10, whereby the single tryptophan residue (Trp25) is buried in the lipid bilayer and the tyrosine and histidine residues are exposed to the aqueous solvent.
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PMID:Investigation of the membrane-active peptides melittin and glucagon by photochemically induced dynamic-nuclear-polarization (photo-CIDNP) NMR. 200 94

Immunoreactivity of antisera directed against human neuropeptide Y (NPY), anglerfish polypeptide YG (aPY), bovine pancreatic polypeptide (bPP), salmon pancreatic polypeptide (sPP), porcine peptide tyrosine tyrosine (PYY), and salmon glucagon-like peptide (GLP) was investigated in the endocrine pancreas and anterior intestine of adult lampreys, Petromyzon marinus, by immunohistochemical analysis. There was no immunoreactivity to anti-sPP and anti-bPP in any tissue and anti-GLP immunostaining was only present in the anterior intestine. The immunoreactivity to antisera raised against NPY, aPY, and PYY was colocalized within the same small number of cells in the caudal and cranial pancreas of juveniles and the caudal pancreas of upstream migrant adults. These antibodies did not immunostain B- or D-cells and thus, NPY, aPY, and PYY were likely localized in a third cell type (3a) in the lamprey pancreas. Immunostaining of a few cells with only anti-aPY suggested the possibility of a fourth cell type (3b). Immunoreactivity was similar in the cranial and caudal pancreas of male upstream migrants; however, in the female cranial pancreas, a few cells demonstrated intense immunoreaction to anti-aPY, while weaker immunostaining with this antiserum was observed in B-cells. In the intestine of juvenile and upstream migrant lampreys, positive immunostaining to GLP, NPY, aPY, and PYY antibodies was colocalized within the same cell. We believe that this cell may contain PYY/glucagon family peptides. Other intestinal cells immunostained with either GLP or somatostatin-34 antiserum.
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PMID:Immunoreactivity to peptides belonging to the pancreatic polypeptide family (NPY, aPY, PP, PYY) and to glucagon-like peptide in the endocrine pancreas and anterior intestine of adult lampreys, Petromyzon marinus: an immunohistochemical study. 202 16

Purified pancreatic Beta cells were labelled with 3H-tyrosine before studying their secretory activity in perifusion. At 1.4 mmol/l glucose, the cells released similar fractions (0.01% per min) of their contents in preformed and in newly formed insulin. At 20 mmol/l glucose plus 10(-8) mol/l glucagon, these fractional release rates increased by 16 and 40-fold respectively. The preferential release of newly synthesized as compared to stored insulin is attributable to a heterogeneity in individual cell responses. The secretory responsiveness to glucose plus glucagon was completely suppressed by 10(-7) mol/l clonidine. Insulin induced a 20% reduction at 10(-6) mol/l, but remained without effect at 10(-7) mol/l. Insulin-like growth factor-I provoked a 30% decrease at 5.10(-9) mol/l. It is concluded that the type-I insulin-like growth factor receptors on pancreatic Beta cells mediate a suppressive action on the insulin release process. Their high affinity for insulin-like growth factor-I allows physiologic levels of this peptide to participate in the regulation of insulin release. Their low affinity for insulin provides the basis for a minor feedback action by this hormone at concentrations exceeding the normal circulating levels.
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PMID:Direct effect of insulin and insulin-like growth factor-I on the secretory activity of rat pancreatic beta cells. 207 97

We examined the level of plasma amino acids, glucose, immunoreactive insulin (IRI) and immunoreactive glucagon (IRG) of patients in the fasted state with acute hepatitis in the actual acute stage (AHa), acute hepatitis in the convalescent stage (AHc), chronic active hepatitis (CAH), chronic persistent hepatitis (CPH) and liver cirrhosis (LC). In AHa patients, the plasma glucose (FPG), plasma alanine (Ala), tryptophan (Trp) and histidine (His) levels were significantly lower and plasma cystine (Cys) level significantly higher than the control levels. This however, was not the case in the other patients. The glutamic acid (Glu) concentration was significantly higher in AHa (p less than 0.02), CAH (p less than 0.001) and CPH (p less than 0.001) and the tyrosine (Tyr) concentration was significantly higher in AHa (p less than 0.02), CPH (p less than 0.001), CAH (p less than 0.001) and LC (p less than 0.001) than they were in the controls. The lysine (Lys) concentration was significantly raised in the AHa (p less than 0.02) and CPH (p less than 0.05) cases. The IRG level was significantly higher in AHa (p less than 0.001), in AHc (p less than 0.01) and LC (p less than 0.01). Valine (Val) showed a significant decrease in concentration in AHa (p less than 0.01) and LC (p less than 0.001).(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Profiles of plasma amino acids in fasted patients with various liver diseases. 208 40

Vasoactive intestinal peptide (VIP) has been implicated as a physiological PRL-releasing factor; however, characterization of VIP receptors on normal pituitaries using radioligand-binding methods has been problematic. In this study we demonstrated specific receptors for VIP in anterior pituitary glands of female rats using HPLC-purified monoiodinated [Tyr(125I)10]VIP. Binding of VIP was reversible, saturable to receptor and radioligand, regulated by guanine nucleotides, and dependent on time and temperature. Scatchard analysis of competitive binding studies indicated high and low affinity binding sites, with equilibrium dissociation constants (Kd) of 0.19 +/- 0.03 and 28 +/- 16 nM, respectively. The corresponding maximum numbers of binding sites were 158 +/- 34 fmol/mg and 11.7 +/- 6.9 pmol/mg. Binding was specific, as peptides with structural homology to VIP were less than 100th as potent as VIP. The rank order of potency of the peptides tested was VIP greater than rat (r) peptide histidine isoleucine = human (h) PHI greater than rGRF greater than bovine GRF = porcine PHI = VIP-(10-28) greater than hGRF greater than secretin greater than apamin greater than glucagon. Radioligand binding was associated primarily with lactotrope-enriched fractions prepared by unit gravity sedimentation of dispersed anterior pituitary cells. VIP stimulated PRL release from cultured rat anterior pituitary cells, with an ED50 of 1 nM. These results, comprising the first identification of specific VIP receptors in normal rat anterior pituitary tissue using radioligand-binding methods, provide additional support for a biological role of VIP in lactotrope function.
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PMID:Receptors for vasoactive intestinal peptide in rat anterior pituitary glands: localization of binding to lactotropes. 215 75

Brain natriuretic peptide (BNP) is a recently discovered family of natriuretic peptides highly homologous to atrial natriuretic factor (ANF). Quantitative in vitro autoradiography with a computerized microdensitometer demonstrated that the distribution of BNP binding sites is similar to the known distribution pattern of ANF binding sites in rat tissues. Analysis of saturation and competition curves disclosed that the maximal binding capacity for BNP-(Asp-81--Tyr-106) and ANF-(Ser-99--Tyr-126) is similar within the plexiform layer of the olfactory bulb, the choroid plexus, and the adrenal zona glomerulosa. Examination of the competition curves of BNP-(Asp-81--Tyr-106), ANF-(Ser-99--Tyr-126), and des-(Gln-116--Gly-120)ANF-(Asp-102--Cys-121)NH2 (C-ANF, a ligand highly specific for ANF-R2 receptors) for 125I-labeled BNP-(Asp-81--Tyr-106) and 125I-labeled ANF-(Ser-99--Tyr-126) binding revealed that ANF fully displaced 125I-BNP binding and, conversely, BNP completely displaced 125I-ANF binding in these tissues, whereas C-ANF partially displaced 125-BNP and 125-ANF binding. Angiotensin II, insulin, glucagon, and substance P had no influence on 125I-BNP binding in the above tissues. These results support the view that BNP and ANF share the same binding sites in rats.
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PMID:Brain natriuretic peptide binding sites in rats: in vitro autoradiographic study. 216 36


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