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GHRP-6

Growth Hormone Releasing Peptide-6, Growth hormone-releasing hexapeptide, His-D-Trp-Ala-Trp-D-Phe-Lys-NH2

A synthetic hexapeptide that stimulates growth hormone secretion by mimicking ghrelin and binding to GHS receptors in the pituitary gland.

Quick Stats
Studies 702
Trials 0
Formula C46H56N12O6
Overview Studies 702 Clinical Trials 0
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pubmed Jun 17, 2011

The Peptidic GHS-R antagonist [D-Lys(3)]GHRP-6 markedly improves adiposity and related metabolic abnormalities in a mouse model of postmenopausal obesity.

Maletínská. L L; Matyšková. R R; Maixnerová. J J; Sýkora. D D; P&#xfd...

It was demonstrated that estrogen deficiency and consuming high fat (HF) diet enhanced orexigenic activity of ghrelin. Therefore, we hypothesized that antagonizing of ghrelin action would attenuate food intake and body weight in mice obese both from ovariectomy (OVX) and feeding a HF diet. Ghrelin receptor antagonist [D-Lys(3)]GHRP-6 after seven days of subcutaneous treatment markedly decreased food intake in OVX mice fed both HF and standard diets; furthermore, it reduced body weight and blood glucose, insulin and leptin, and increased β-hydroxybutyrate level and uncoupling-protein-1 mRNA in brown adipose tissue. Pair-feeding revealed that effect of [D-Lys(3)]GHRP-6 was primary anorexigenic. Estrogen supplementation reduced anorexigenic effects of [D-Lys(3)]GHRP-6. OVX [D-Lys(3)]GHRP-6 treatment in mice on HF diet resulted in markedly increased circulating level and liver expression of a major metabolic regulator, fibroblast growth factor 21. Our data suggest that ghrelin antagonists could be especially beneficial in individuals with common obesity combined with estrogen deficiency.

pubmed Aug 31, 2018

A stable meta-carborane enables the generation of boron-rich peptide agonists targeting the ghrelin receptor.

Worm. Dennis J DJ; Els-Heindl. Sylvia S; Kellert. Martin M; Kuhnert. Robert R; Saretz. Stefan S; Koe...

Scientists attached a special boron cluster to short peptides like GHRP‑6 to make them carry boron into cells that have the ghrelin receptor, aiming to improve a cancer treatment called boron neutron capture therapy. The work is about drug design for tumors, not about boosting metabolism, muscle, or brain performance.

pubmed Jan 22, 2013

Central ghrelin signaling mediates the metabolic response of C57BL/6 male mice to chronic social defeat stress.

Patterson. Z R ZR; Khazall. R R; Mackay. H H; Anisman. H H; Abizaid. A A

Chronic stressors promote metabolic disturbances, including obesity and metabolic syndrome. Ghrelin, a peptide that promotes appetite and the accumulation of adipose tissue, is also secreted in response to stressors to protect the brain and peripheral tissues from the effects of these stressors. Here we demonstrate that elevated ghrelin levels produced by chronic exposure to social stress are associated with increased caloric intake and body weight gain in male C57BL mice. In contrast, stressed mice lacking ghrelin receptors (GHSR KO mice) or C57BL mice receiving chronic intracerebroventricular delivery of the ghrelin receptor antagonist [d-Lys(3)]-GHRP-6 show attenuated weight gain and feeding responses under the same social stress paradigm. Interestingly, stressed GHSR KO mice showed depleted sc and intrascapular brown fat depots, whereas stressed young wild-type mice did not. In old wild-type mice, chronic social defeat increased visceral and intrascapular brown fat depots in association with increases in obesity markers like hyperleptinemia and hyperinsulinemia along with increased hypothalamic expression of neuropeptide Y and Agouti related peptide. Importantly, the elevated expression of these peptides persisted least for 2 weeks after cessation of the stressor regimen. In contrast, old GHSR KO mice did not show these alterations after chronic social defeat. These results suggest that ghrelin plays an important role in the metabolic adaptations necessary to meet the energetic demands posed by stressors, but chronic exposure to stress-induced ghrelin elevations ultimately could lead to long lasting metabolic dysfunctions.

pubmed May 9, 2017

Hypoglycemic Effect of Combined Ghrelin and Glucagon Receptor Blockade.

Mani. Bharath K BK; Uchida. Aki A; Lee. Young Y; Osborne-Lawrence. Sherri S; Charron. Maureen J MJ;...

Glucagon receptor (GcgR) blockade has been proposed as an alternative to insulin monotherapy for treating type 1 diabetes since deletion or inhibition of GcgRs corrects hyperglycemia in models of diabetes. The factors regulating glycemia in a setting devoid of insulin and glucagon function remain unclear but may include the hormone ghrelin. Not only is ghrelin release controlled by glucose but also ghrelin has many actions that can raise or reduce falls in blood glucose level. Here, we tested the hypothesis that ghrelin rises to prevent hypoglycemia in the absence of glucagon function. Both GcgR knockout (<i>Gcgr</i><sup>-/-</sup>) mice and <i>db</i>/<i>db</i> mice that were administered GcgR monoclonal antibody displayed lower blood glucose levels accompanied by elevated plasma ghrelin levels. Although treatment with the pancreatic &#x3b2;-cell toxin streptozotocin induced hyperglycemia and raised plasma ghrelin levels in wild-type mice, hyperglycemia was averted in similarly treated <i>Gcgr</i><sup>-/-</sup> mice and the plasma ghrelin level was further increased. Notably, administration of a ghrelin receptor antagonist further reduced blood glucose levels into the markedly hypoglycemic range in overnight-fasted, streptozotocin-treated <i>Gcgr</i><sup>-/-</sup> mice. A lowered blood glucose level also was observed in overnight-fasted, streptozotocin-treated ghrelin receptor-null mice that were administered GcgR monoclonal antibody. These data suggest that when glucagon activity is blocked in the setting of type 1 diabetes, the plasma ghrelin level rises, preventing hypoglycemia.

pubmed Apr 4, 2014

N-aminoimidazolidin-2-one peptidomimetics.

Doan. Ngoc-Duc ND; Hopewell. Robert R; Lubell. William D WD

Scientists created a new chemical building block (Aid) that makes peptide chains stiffer and reported how they made 25 different versions, including eight that look like the peptide GHRP‑6. The paper focuses on the chemistry of making these molecules, not on how they work in the body or how to use them.

pubmed 2015

Growth hormone-releasing peptide-biotin conjugate stimulates myocytes differentiation through insulin-like growth factor-1 and collagen type I.

Lim. Chae Jin CJ; Jeon. Jung Eun JE; Jeong. Se Kyoo SK; Yoon. Seok Jeong SJ; Kwon. Seon Deok SD; Lim...

Based on the potential beneficial effects of growth hormone releasing peptide (GHRP)-6 on muscle functions, a newly synthesized GHRP-6-biotin conjugate was tested on cultured myoblast cells. Increased expression of myogenic marker proteins was observed in GHRP-6-biotin conjugate-treated cells. Additionally, increased expression levels of insulin-like growth factor-1 and collagen type I were observed. Furthermore, GHRP-6-biotin conjugate-treated cells showed increased metabolic activity, as indicated by increased concentrations of energy metabolites, such as ATP and lactate, and increased enzymatic activity of lactate dehydrogenase and creatine kinase. Finally, binding protein analysis suggested few candidate proteins, including desmin, actin, and zinc finger protein 691 as potential targets for GHRP6-biotin conjugate action. These results suggest that the newly synthesized GHRP-6-biotin conjugate has myogenic stimulating activity through, at least in part, by stimulating collagen type I synthesis and several key proteins. Practical applications of the GHRP-6-biotin conjugate could include improving muscle condition.

pubmed Oct 5, 2013

Involvements of the lateral hypothalamic area in gastric motility and its regulation by the lateral septum.

Gong. Yanling Y; Xu. Luo L; Wang. Hongbo H; Guo. Feifei F; Sun. Xiangrong X; Gao. Shengli S

Ghrelin is an endogenous ligand for the growth hormone secretagogue receptor (GHS-R) pre-dominantly produced in the stomach. Recent studies have shown that it may promote food intake and gastric motility. We aim to explore effects of ghrelin on the gastric distension (GD) sensitive neurons and gastric motility in the lateral hypothalamic area (LHA), and the possible regulation by the lateral septum. Extracellular single unit discharges were recorded and the gastric motility was monitored by administration of ghrelin into LHA and electrical stimulation of lateral septum. Expression of GHS-R was determined by polymerase chain reaction (PCR), western blot and immunohistochemistry staining. Projection of nerve fiber and expression of ghrelin were observed by retrograde tracer and fluo-immunohistochemistry staining. Results revealed that there were GD neurons in the LHA, and administration of ghrelin could excite both GD-excitatory (GD-E) and GD-inhibited (GD-I) neurons in the LHA. The gastric motility was significantly promoted by administration of ghrelin into LHA with a dose dependent manner, which could be completely abolished by treatment with ghrelin receptor antagonist [D-Lys-3]-GHRP-6 or BIM-28163. c-Fos expression was significantly increased after ghrelin administration to the LHA. Electrical stimulation of the lateral septum could significantly excite GD neurons responsive to ghrelin in the LHA as well as promote gastric motility. However, those effects could be absorbed by pre-treatment of [D-Lys-3]-GHRP-6. GHSR-1a expression in the LHA had no change after ghrelin administration to the LHA or electrical stimulating lateral septum. Electrical lesion of the LHA resulted in the decrease of gastric motility. GHS-R and Ghrelin/FG-double labeled neurons were observed in the LHA and lateral septum, respectively. It is suggested that the LHA may involve in promoting gastric motility via ghrelin. The Lateral septum projects to the LHA and exerts some regulating function on the LHA.

pubmed Oct 15, 2018

Hemostatic effect of acylated ghrelin in control and sleeve gastrectomy-induced rats: mechanisms of action.

Morsy. Mohamed Darwesh MD

This study investigated the effect of acylated ghrelin (AG) deficiency after sleeve gastrectomy (SG) or chronic administration in control and SG-indiuced rats on platelet function, coagulation, and fibrinolysis. Administration of AG (100&#x2009;&#xb5;g/kg, subcutaneously) to control or SG rats significantly inhibited platelets aggregation and lowered levels of Von-Willebrand factor (vWF), fibrinogen, and thromboxane B2. Concomitantly, it decreased circulatory levels and aortic expression levels of plasminogen activator inhibitor-1 (PAI-1) and tissue factor (TF) and increased the aortic expression of the endothelial nitric oxidase (eNOS). However, AG inhibited angiotensin-II (ANGII)-induced upregulation of tissue factor pathway inhibitor (TPAI) and TF and increased activity of TF and increases eNOS expression in cultured endothelial cells, an effect that was abolished by the addition of D-[lys3]-GHRP-6, a selective AG receptor (GHSR-1a) blocker or L-Name, a potent eNOS inhibitor. In conclusion, AG has an anti-platelet, anti-coagulant, and fibrinolytic roles mediated through GHSR-1a to enhance nitric oxide synthesis.

pubmed Jul 21, 2011

Structure-activity relationships of GHRP-6 azapeptide ligands of the CD36 scavenger receptor by solid-phase submonomer azapeptide synthesis.

Sabatino. David D; Proulx. Caroline C; Pohankova. Petra P; Ong. Huy H; Lubell. William D WD

The cluster of differentiation 36 (CD36) class B scavenger receptor binds a variety of biologically endogenous ligands in addition to synthetic peptides (i.e., growth hormone-releasing peptides, GHRPs), which modulate biological function related to anti-angiogenic and anti-atherosclerotic activities. Affinity labeling had previously shown that GHRP-6 analogues such as hexarelin, [2-Me-W(2)]GHRP-6 (1), bind to the lysine-rich domain of the CD36 receptor. Moreover, the azapeptide analogue [aza-F(4)]GHRP-6, 2, exhibited a characteristic &#x3b2;-turn conformation as described by CD and NMR spectroscopy and a slightly higher CD36 binding affinity relative to hexarelin (1.34 and 2.37 &#x3bc;M, respectively), suggesting receptor binding was mediated by the conformation and the aromatic residues of these peptide sequences. Ligand-receptor binding interactions were thus explored using azapeptides to examine influences of side-chain diversity and backbone conformation. In particular, considering that aromatic cation interactions may contribute to binding affinity, we have explored the potential of introducing salt bridges to furnish GHRP-6 azapeptide ligands of the CD36 receptor. Fifteen aza-glutamic acid analogues related to 2 were prepared by submonomer solid-phase synthesis. The azapeptide side chains were installed by novel approaches featuring alkylation of resin-bound semicarbazone with Michael acceptors and activated allylic acetates in the presence of phosphazene base (BTPP). Moreover, certain Michael adducts underwent intramolecular cyclization during semicarbazone deprotection, leading to novel pyrrazoline and aza-pyroglutamate N-terminal residues. Structural studies indicated that contingent on sequence the [aza-Glu]GHRP-6 analogues exhibited CD spectra characteristic of random coil, polyproline type II and &#x3b2;-turn secondary structures in aqueous media. In covalent competition binding studies with the GHRP-6 prototype hexarelin bearing a radiotracer, certain [aza-Glu]GHRP-6 azapeptides retained relatively high (2-27 &#x3bc;M) affinity for the CD36 scavenger receptor.

pubmed Feb 13, 2012

GHRP-6 mimics ghrelin-induced stimulation of food intake and suppression of locomotor activity in goldfish.

Yahashi. Satowa S; Kang. Ki Sung KS; Kaiya. Hiroyuki H; Matsuda. Kouhei K

Ghrelin was first identified and characterized from rat stomach as an endogenous ligand for the growth hormone secretagogue (GHS) receptor (GHS-R). Ghrelin also acts as an orexigenic factor and regulates energy balance in rodents. In goldfish, native ghrelin consists of 11 molecular variants, the major form being a 17-residue peptide with n-octanoic acid modification (n-octanoyl ghrelin17), and intraperitoneal (IP) administration of n-octanoyl ghrelin17 induces central actions such as stimulation of food intake and suppression of locomotor activity through capsaicin-sensitive afferents. Four types of GHS-Rs (1a-1, 1a-2, 2a-1 and 2a-2) have been identified in goldfish, and one GHS, GHRP-6, can activate only GHS-R2a-1 in vitro. However, there is no information about the effect of GHRP-6 on food intake and locomotor activity in goldfish in vivo. Therefore, in the present study, we examined whether IP-administered GHRP-6 would mimic the orexigenic action of n-octanoyl ghrelin17 and its suppression of locomotor activity. IP administration of GHRP-6 at 1pmol/g body weight (BW) stimulated food intake, and was equipotent to the orexigenic action of n-octanoyl ghrelin17 at 10 pmol/g BW. IP-injected GHRP-6 at 1 pmol/g BW also induced a significant decrease of locomotor activity, as was the case for IP-injected n-octanoyl ghrelin17 at 10 pmol/g BW. The action of GHRP-6 was blocked by IP-preinjected capsaicin at 160 nmol/g BW. These results suggest that the central action of GHRP-6 might be mediated via the GHS-R2a-1-signaling pathway, and subsequently through capsaicin-sensitive afferents in goldfish.

pubmed Dec 13, 2013

Multicomponent diversity-oriented synthesis of aza-lysine-peptide mimics.

Zhang. Jinqiang J; Proulx. Caroline C; Tomberg. Anna A; Lubell. William D WD

Scientists developed a new chemistry trick to attach special building blocks to a peptide called GHRP‑6, creating 18 slightly different versions. The work is about how to make these modified peptides in the lab, not about how they work in the body or how to use them for health.