Effect of calcitonin gene-related peptide on skeletal muscle via specific binding site and G protein

1989 ◽  
Vol 90 (1) ◽  
pp. 99-109 ◽  
Author(s):  
Masaharu Takamori ◽  
Hiroaki Yoshikawa
Keyword(s):  
Skeletal Muscle ◽  
Binding Site ◽  
G Protein ◽  
Specific Binding ◽  
Calcitonin Gene Related Peptide ◽  
Related Peptide ◽  
Calcitonin Gene

scholarly journals Cross-reactivity of amylin with calcitonin-gene-related peptide binding sites in rat liver and skeletal muscle membranes

1991 ◽  
Vol 277 (1) ◽  
pp. 139-143 ◽  
Author(s):  
A Chantry ◽  
B Leighton ◽  
A J Day
Keyword(s):  
Skeletal Muscle ◽  
Binding Site ◽  
Rat Liver ◽  
Specific Binding ◽  
Calcitonin Gene Related Peptide ◽  
Cross Reactivity ◽  
Scatchard Analysis ◽  
Human Calcitonin ◽  
Related Peptide ◽  
Calcitonin Gene

This study examines whether the high degree of sequence identity between amylin and calcitonin-gene-related peptide (CGRP) is reflected in their cross-reactivity at the level of membrane receptor binding. Rat liver plasma membranes contain a specific saturable binding site for 125I-labelled human CGRP-1. Binding reached equilibrium within 30 min and was rapidly reversed by re-incubating membranes in the presence of 1 microM human CGRP. In addition, the presence of 50 mM- or 500 mM-NaCl lowered specific binding by 30% and 77% respectively. Scatchard analysis was consistent with a single high-affinity site with a dissociation constant (Kd) of 0.125 nM and binding capacity (Bmax.) of 580 fmol/mg of membrane protein. Specific binding of 125I-labelled human CGRP-1 to both liver and skeletal muscle membranes was inhibited by human CGRP-1 [IC50 (concn. causing half-maximal inhibition of binding) 0.1-0.3 nM], and rat amylin (IC50 10 nM), but not by human calcitonin. Covalent cross-linking of 125I-CGRP to its binding site in rat skeletal muscle and liver membranes resulted in labelling of a major species of about 70 kDa under reducing conditions and about 55 kDa under alkylating conditions, as visualized on SDS/PAGE. These radiolabelled species were absent in the presence of CGRP or amylin at 1 microM. These results are indicative of a common binding site for both CGRP and amylin in liver and skeletal muscle, and it is suggested that both peptides mediate their actions through the same effector system. The normal physiological importance and the relevance to the pathology of type 2 diabetes of these data are discussed.

Solubilization and Characterization of Calcitonin Gene-Related Peptide Binding Site from Porcine Spinal Cord

1988 ◽  
Vol 50 (2) ◽  
pp. 480-485 ◽  
Author(s):  
Osamu Hiroshima ◽  
Yoshihisa Sano ◽  
Teruaki Yuzuriha ◽  
Chiyuki Yamato ◽  
Akira Saito ◽  
...  
Keyword(s):  
Spinal Cord ◽  
Binding Site ◽  
Peptide Binding ◽  
Calcitonin Gene Related Peptide ◽  
Related Peptide ◽  
Calcitonin Gene ◽  
Peptide Binding Site

scholarly journals A rat skeletal muscle cell line (L6) expresses specific adrenomedullin binding sites but activates adenylate cyclase via calcitonin gene-related peptide receptors

1996 ◽  
Vol 318 (1) ◽  
pp. 241-245 ◽  
Author(s):  
Hedley A COPPOCK ◽  
Ali A OWJI ◽  
Stephen R BLOOM ◽  
David M SMITH
Keyword(s):  
Protein Kinase ◽  
Adenylate Cyclase ◽  
Binding Site ◽  
Binding Sites ◽  
Calcitonin Gene Related Peptide ◽  
Dependent Protein Kinase ◽  
Related Peptide ◽  
Camp Dependent Protein Kinase ◽  
Calcitonin Gene ◽  
Dependent Protein

We have previously demonstrated specific binding sites for adrenomedullin, a novel member of the calcitonin family of peptides, in rat muscles. It is unclear whether these receptors are vascular or muscular. Receptors for the structurally similar calcitonin gene-related peptide (CGRP) are present on myocytes and might be involved in the regulation of myocyte glucose metabolism and control by motor neurons. We investigated whether adrenomedullin binding sites were present on L6 myocytes. Specific [125I]adrenomedullin binding sites were demonstrated where adrenomedullin competed with an IC50 of 0.22±0.04 nM (mean±S.E.M.) and a concentration of binding sites (Bmax) of 0.95±0.19 pmol/mg of protein (mean±S.E.M.). CGRP and the specific CGRP receptor antagonist CGRP(8–37) competed weakly at this site (IC50 > 10 and 601±298 nM respectively). Binding studies with [125I]CGRP revealed a binding site for CGRP (IC50 = 0.13±0.01 nM; Bmax = 0.83±0.10 pmol/mg of protein) where both CGRP(8–37) and adrenomedullin competed with [125I]CGRP with IC50 values of 1.15±0.12 and 8.68±0.98 nM respectively. Chemical cross-linking showed the CGRP and adrenomedullin binding site–ligand complexes to have approximate molecular masses of 82 and 76 kDa respectively. Both CGRP and adrenomedullin increased adenylate cyclase activity with similar potencies. In both cases adenylate cyclase activation was blocked by CGRP(8–37). Stimulation with 10 nM adrenomedullin or CGRP caused an increase in the percentage of total activated cellular cAMP-dependent protein kinase from 38% in resting cells to 100% and 98% respectively. Therefore in L6 cells adrenomedullin can bind to CGRP receptors, activating adenylate cyclase and cAMP-dependent protein kinase.

Characterization of specific calcitonin gene related peptide receptors present in hamster pancreatic β cells

1993 ◽  
Vol 13 (4) ◽  
pp. 221-231 ◽  
Author(s):  
A. Barakat ◽  
G. Rosselin ◽  
J.-C. Marie
Keyword(s):  
Adenylate Cyclase ◽  
Cell Membranes ◽  
Specific Binding ◽  
Calcitonin Gene Related Peptide ◽  
Receptor Subtypes ◽  
Cgrp Receptor ◽  
Β Cells ◽  
Related Peptide ◽  
Insulinoma Cell ◽  
Calcitonin Gene

Calcitonin gene-related peptide (CGRP) shares about 46% and 20% amino acid sequence homology with islet amyloid polypeptide (IAPP) and salmon calcitonin (sCT). We investigated whether these related peptides could cross-react with the specific binding of 125I-[His]hCGRP I to the CGRP receptor in hamster insulinoma cell membranes. A rapid dissociation of membrane bound 125I-[His]hCGRP I could be induced in the presence of 1 μM chicken CGRP (cCGRP). The specific 125I-[His]hCGRP I binding was inhibited by the related peptides and their half-maximal inhibitory concentrations (IC50) were: cCGRP (0.1 nM), rat CGRP I and human CGRP I and II (1.0–2.0 nM), fragment of hCGRP I (8–37) (150 nM), human IAPP (440 nM). The non-amidated form of hIAPP; human diabetes-associated peptide (hDAP) did not inhibit the binding of 125I-[His]hCGRP I and sCT was only effective at a high concentration (1 μM). Binding of 125I-[His]hCGRP I was dose dependently inhibited by guanosine-5′-O-(3-thiotriphosphate) or (GTPγS) and a 70% reduction of binding was obtained with 0.1 mM GTPγS. The IC50 value of cCGRP (0.1 nM) was increased 100-fold in the presence of 0.1 mM GTPγS. Human CGRP I and cCGRP at 2.5 μM did not stimulate the activity of hamster insulinoma cell membranes adenylate cyclase, while glucagon (1 μM) induced a 2-fold increase. Thus, specific CGRP receptors present in hamster β cells are associated with G protein (s) and IAPP can interact with these receptors. These results and the observation that cCGRP and hCGRP I did not influence adenylate cyclase activity provide further evidence for CGRP receptor subtypes.

scholarly journals The role of the sensory peptide calcitonin-gene-related peptide(s) in skeletal muscle carbohydrate metabolism: effects of capsaicin and resiniferatoxin

1995 ◽  
Vol 307 (3) ◽  
pp. 707-712 ◽  
Author(s):  
B Leighton ◽  
E A Foot
Keyword(s):  
Skeletal Muscle ◽  
Soleus Muscle ◽  
Glycogen Synthesis ◽  
Calcitonin Gene Related Peptide ◽  
Sensory Nerves ◽  
Muscle Fibres ◽  
Related Peptide ◽  
Calcitonin Gene

1. The content of calcitonin-gene-related-peptide-like immunoreactivity (CGRP-LI) in various rat muscles was measured. Starvation for 24 h did not affect the content of CGRP-LI in these muscles, except for a decreased level in the starved-rat diaphragm. Higher contents of CGRP-LI were observed in well-vascularized muscles. 2. Capsaicin (at 1, 10 and 100 microM) inhibited insulin-stimulated rates of glycogen synthesis in isolated stripped incubated soleus muscle preparations by a mechanism independent of catecholamine release, since the effects of capsaicin were not altered by the beta-adrenoreceptor antagonist DL-propranolol. 3. Resiniferatoxin (10 nM), which is a potent capsaicin agonist, also significantly inhibited the insulin-stimulated rate of glycogen synthesis. Furthermore, the concentration of resiniferatoxin required to inhibit glycogen synthesis was 100 times less than the concentration of capsaicin needed for the same effect. 4. Capsaicin (10 microM) decreased the content of CGRP-LI in isolated stripped incubated soleus muscle preparations by about 40%. 5. Neonatal treatment of rats with capsaicin, which causes de-afferentation of some sensory nerves such, we hypothesize, that CGRP can no longer be released to counteract the effects of insulin in vivo, caused increased rates of glycogen synthesis and increased glycogen content in stripped soleus muscle preparations in vitro when muscles were isolated from the adult rats. 6. These findings support the hypothesis that capsaicin and resiniferatoxin elicit an excitatory response on sensory nerves in skeletal muscle in vitro to cause the efferent release of CGRP. Consequently, CGRP is delivered to skeletal muscle fibres to inhibit insulin-stimulated glycogen synthesis. The role of CGRP in recovery of blood glucose levels during hypoglycaemia is discussed.

Sign in / Sign up

Export Citation Format

Share Document