cortistatin-14 has been researched along with hexarelin* in 2 studies
2 other study(ies) available for cortistatin-14 and hexarelin
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Cortistatin-8, a synthetic cortistatin-derived ghrelin receptor ligand, does not modify the endocrine responses to acylated ghrelin or hexarelin in humans.
Cortistatin (CST), a neuropeptide with high structural homology with somatostatin (SST), binds all SST receptor (SST-R) subtypes but, unlike SST, also shows high binding affinity to ghrelin receptor (GHS-R1a). CST exerts the same endocrine activities of SST in humans, suggesting that the activation of the SST-R might mask the potential interaction with ghrelin system. CST-8, a synthetic CST-analogue devoid of any binding affinity to SST-R but capable to bind the GHS-R1a, has been reported able to exert antagonistic effects on ghrelin actions either in vitro or in vivo in animals. We studied the effects of CST-8 (2.0 microg/kg i.v. as a bolus or 2.0 microg/kg/h i.v. as infusion) on both spontaneous and ghrelin- or hexarelin- (1.0 microg/kg i.v. as bolus) stimulated GH, PRL, ACTH and cortisol secretion in 6 normal volunteers. During saline, no change occurred in GH and PRL levels while a spontaneous ACTH and cortisol decrease was observed. As expected, both ghrelin and hexarelin stimulated GH, PRL, ACTH and cortisol secretion (p<0.05). CST-8, administered either as bolus or as continuous infusion, did not modify both spontaneous and ghrelin- or hexarelin-stimulated GH, PRL, ACTH and cortisol secretion. In conclusion, CST-8 seems devoid of any modulatory action on either spontaneous or ghrelin-stimulated somatotroph, lactotroph and corticotroph secretion in humans in vivo. These negative results do not per se exclude that, even at these doses, CST-8 might have some neuroendocrine effects after prolonged treatment or that, at higher doses, may be able to effectively antagonize ghrelin action in humans. However, these data strongly suggest that CST-8 is not a promising candidate as GHS-R1a antagonist for human studies to explore the functional interaction between ghrelin and cortistatin systems. Topics: Acylation; Adrenocorticotropic Hormone; Adult; Ghrelin; Human Growth Hormone; Humans; Hydrocortisone; Infusions, Intravenous; Injections, Intravenous; Ligands; Male; Neuropeptides; Oligopeptides; Prolactin; Receptors, Ghrelin | 2008 |
Cortistatin, but not somatostatin, binds to growth hormone secretagogue (GHS) receptors of human pituitary gland.
Antagonism between GH secretagogues (GHS) and somatostatin (SRIH) has been postulated and demonstrated, but SRIH does not bind to GHS receptors (GHS-R) and potent synthetic peptidyl GHS (GHRP6, hexarelin) do not displace radiolabeled SRIH from its receptors. However, non-natural SRIH octapeptide agonists (mainly lanreotide and vapreotide) displace 125I-Tyr-Ala-hexarelin from pituitary binding sites suggesting that an endogenous factor related to SRIH might exist and interact with GHS-R. Our aims were to investigate the ability of different SRIH-like peptides such as various SRIH fragments (SRIH 3-14, SRIH 7-14, SRIH 3-10, SRIH 7-10, SRIH 2-9) and a natural neuropeptide that shows a high structural homology with SRIH such as cortistatin-14 (CST) to compete with 125I-Tyr-Ala-hexarelin for human pituitary binding sites and to compare their binding affinity with that of hexarelin and ghrelin, a gastric-derived peptidyl GHS that has been proposed as a natural ligand of GHS-R. While the binding of 125I-Tyr-Ala-hexarelin to pituitary membranes was completely displaced by unlabelled hexarelin, ghrelin and CST, none of the SRIH fragments tested inhibited this binding. Ghrelin and CST exhibited a similar affinity (4.6-5.4 x 10(-7) mol/l) for the binding while hexarelin was more effective by about four orders of magnitude in displacing 125I-Tyr-Ala-hexarelin. Our data demonstrate for the first time that cortistatin, a natural peptide related to SRIH, binds to GHS-R and suggest that this factor may play a role in modulating the activity of these receptors. Topics: Adult; Binding, Competitive; Cell Membrane; Female; Ghrelin; Humans; Male; Middle Aged; Neuropeptides; Oligopeptides; Peptide Hormones; Peptides; Pituitary Gland; Receptors, Cell Surface; Receptors, G-Protein-Coupled; Receptors, Ghrelin; Somatostatin | 2001 |