• Asian-Australasian Journal of Animal Sciences
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• 제15권5호
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• pp.757-766
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• 2002

Growth hormone-releasing peptide-2 (GHRP-2, also named KP102) is a new hexapeptide of a series of synthetic growth hormone-releasing peptides (GHRPs) which stimulates the secretion of growth hormone (GH) in vitro and in vivo in several species including calf, sheep and pig. The GH-releasing activity of GHRP-2 is two to three times more effective than that of the original GHRP-6, and GHRP-1 in the rats and humans. To date, GHRP-2 seems to be the most potent member of the family of GHRPs. Since the GHRPs are short peptides (5-7 amino acid residues), they are synthesized easily and are not as readily degraded in plasma as GHreleasing hormone (GHRH). These features ameliorate their potential on domestic animals because of their chemical nature the GHRPs are efficacious when administered i.v. orally or orally. However, studies in cow, pig and sheep do not indicate such a close relationship between GHRH, somatostatin (SS) and GH, calling into question the general applicability of the human and rat models. Perhaps there is an important role for an endogenous GHRP in the regulation of GH secretion in domestic animals. This review provides an overview on the current knowledge of physiological role of GHRP-2 in domestic animals.

• 생명과학회지
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• 제18권7호
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• pp.931-939
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• 2008

본연구는 정상으로 단백질을 급여한 거세면양에 있어서 에너지 첨가가 GHRP-2투여에 대한 IGF-1 및 IGFBPs에 대한 반응과, 고에너지 급여에 따른 GHRP-2투여가 hepatic GH 수용체에 미치는 영향을 검증하기 위하여 실시하였다. 시험 결과 HENP (CP 0.34 kg, TDN 1.83 kg/day DM intake)처리기간 동안 혈장 IGF-1 과 39-42kDa IGFBP-3수준은 LENP (CP 0.32 kg, TDN 0.87 kg/day DM intake)기간에 비하여 높게 나타났으나 (P<0.05), 혈장 34 kDa IGFBP-2와 24 kDa IGFBP-4는 영양처리에 의해 영향을 받지 않았다. 각 영양처리 기간동안 GHRP-2 ($12.5\;{\mu}g/kg$ body weight/day)투여는 혈장 GH 반응이 촉진되었으며(P<0.05), 혈장 GH 평균 함량과 AUC증가에 있어서는 LENP처리 기간에 비하여 HENP처리기간에서 유의적으로 높게 나타났다(P<0.01). 특히 HENP에서 7일간 GHRP-2투여에 의한 일중 혈장 IGF-1 변화양상을 조사한 결과 투여 2, 6 및 7일에서 뚜렷한 증가양상이 보였다(P<0.05). 이에 반하여 LENP에서는 오직 투여 3일째에서 Saline구에 비하여 유의적인 증가를 확인하였다(P<0.05). IGFBPs의 ligand blotting 결과 HENP구에서 혈장 39-43 kDa IGFBP-3의 수준의 증가가 투여 6일과 7일에서 관찰되었으나 혈장 IGFBP-2수준은 두 영양처리시기에서 유의적인 차이를 관찰하지 못했다. 아울러 HENP구에 있어서 간세포막에 $^{125}I-oGH$의 결합력을 측정한 결과 GHRP-2투여에 의한 영향은 관찰되지 않았다. 이와 같은 결과는 거세면양에 있어서 단백질과 에너지 사이에 영양적 균형은 내인성 GH/IGF-1 axis는 물론 혈장 IGFBP-3수준의 변화에 영향을 미치고 있음을 시사한다.

• Journal of Pharmaceutical Investigation
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• 제31권4호
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• pp.273-279
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• 2001

The purpose of this study is to characterize the iontophoretic transport of growth hormone releasing peptides (GHRP-6) through hairless mouse skin from aqueous solution. The effect of various factors, such as pH, poloarity, current profile, current density, current duration, ionic strength, drug concentration, and enhancer application was studied to obtain basic knowledge on the transport. We have also studied the stability of GHRP-6 in solution with/without current. The donor chamber was filled with phosphate buffer solution containing GHRP-6 and the receptor chamber was filled with phosphate buffer solution (pH 7.4). Ag/AgCl electrode was used for their stability and reversibility. At a predetermined time interval, sampling was made and the concentration of drug was analysed using HPLC system. The results showed that, compared to passive flux, the total amount of drug transported increased markedly by the application of anodal current. Cathodal flux was similar to passive flux. Flux increased with the current density, the duration of current application and drug concentration. The effect of enhancers on the flux was studied using hydrophilic (5% N-methyl pyrrolidone) and hydrophobic (5% propylene glycol monolaurate, 5% oleic acid) enhancers. Application of enhancer also increased the flux.

• BMB Reports
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• 제48권9호
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• pp.501-506
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• 2015

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. [BMB Reports 2015; 48(9): 501-506]

• Asian-Australasian Journal of Animal Sciences
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• 제16권8호
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• pp.1188-1192
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• 2003

Negative feedback on GH responses to GH-releasing hormone (GHRH) and GH-releasing peptides (GHRPs) has been reported and this action has been suggested to act through an increase in somatostatin. To determine whether the acute administration of porcine GH (pGH) inhibits GH responsiveness to GHRP-2 and GHRH in swine, swine were intravenously administered with pGH (5${\mu}g$/kg BW) or placebo followed 180 min later by a second intravenous administration of saline, GHRP-2 (30 ${\mu}g$/kg BW), GHRH (1${\mu}g$/kg BW) and a combination of GHRP-2 and GHRH. Plasma GH concentration was measured by radioimmunoassay. Administration of pGH caused a significant increase in GH area under curve and GH peak concentrations (p<0.001) over placebo-treated group. Plasma GH concentrations peaked at 15 min and returned to baseline level within 90 min. Pretreatment of pGH abolished (p<0.01) GH response to GHRH and attenuated (p<0.05) GH response to GHRP-2 and GHRH combined, without affecting GH response to GHRP-2. These results demonstrate that negative feedback action on GH releasing effect of GHRH occurs in swine, and that GHRP-2 has ability to interact in this action.

• Asian-Australasian Journal of Animal Sciences
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• 제16권8호
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• pp.1193-1198
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• 2003

An increase in frequency of administration of exogenous growth hormone (GH) or GH-releasing hormone was reported to be a model to increase blood circulating insulin-like growth factor-1 (IGF-1) and to improve growth performance in animals. We have investigated the effect of twice daily administration of GH-releasing peptide-2 (GHRP-2) on growth performance, GH responsiveness and plasma insulin-like growth factor IGF-1 in swine. We administered to eight swine, 3 control and 5 treatment, a twice daily s.c. injections of GHRP-2 ($30{\mu}g/kg\;BW$) for a period of 10 days. Every day blood samples immediately taken before injections of GHRP-2 or saline, at 08:00 h and 16:00 h, were measured for IGF-1 concentrations. Blood samples for GH assay were collected every 20 min on days 1, 6 and 10, from 1 hour before and 3 h after GHRP-2 or saline injections at 08:00 h. GH peak concentrations and GH area under curve (GH AUC) on day 1, 6 and 10 in treatment group of swine were higher than those in control swine (p<0.05). Twice daily administration of GHRP-2 caused a significantly attenuation (p<0.05) of GH peak concentrations ($80.25{\pm}13.87$, $39.73{\pm}5.72$ and $27.57{\pm}6.06ng/ml$ for day 1, 6 and 10, respectively) and GH AUCs ($3,536.15{\pm}738.35$, $1,310.31{\pm}203.55$ and $934.37{\pm}208.99ng/ml$ for day 1, 6 and 10, respectively). However, there was no significant difference in GH peak concentration and GH AUC between day 6 and 10. Plasma IGF-1 concentration levels were higher in treatment than control group of swine (p<0.05) after 3 days of the treatment, and the levels reached a plateau from day 3 to 10 of experiment. Growth performance did not alter by GHRP-2 administration, even though a numerical increase of body weight gain and feed efficiency was observed. These results indicate that twice daily administration of GHRP-2 for 10 days in swine did not significantly influence on growth performance, caused an overall attenuation of GH response, and that elevation of plasma GH concentrations caused by GHRP-2 administration increased plasma IGF-1 concentrations, even though an attenuation of GH response was observed.

• 대한약학회:학술대회논문집
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• 대한약학회 2001년도 Proceedings of the Pharmaceutical Society of Korea
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• pp.227.2-227.2
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• 2001

• 대한약학회:학술대회논문집
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• 대한약학회 2001년도 Proceedings of the Pharmaceutical Society of Korea
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• pp.234.2-234.2
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• 2001

• 대한약학회:학술대회논문집
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• 대한약학회 2001년도 Proceedings of International Convention of the Pharmaceutical Society of Korea
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• pp.289.3-290
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• 2001

• Mass Spectrometry Letters
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• 제7권3호
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• pp.55-63
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• 2016

Growth hormone (GH)-releasing peptides (GHRPs) and GH secretagogues (GHSs) are listed in the World Anti-Doping Agency (WADA) Prohibited List. In the present study, we developed and validated a method for the simultaneous analysis of seven GHRPs (alexamorelin, GHRP-1, -2, -4, -5, -6, and hexarelin) and three GHSs (anamorelin, ibutamoren, and ipamorelin) in human urine. Method validation was performed at minimum required performance levels specified by WADA technical documents (2 ng/mL) for all substances, and the method was validated with regard to selectivity (no interference), linearity (R2 > 0.9986), matrix effects (50.0%-141.2%), recovery (10.4%-100.8%), and intra- (2.8%-16.5%) and inter-day (7.0%-22.6%) precisions. The limits of detection for screening and confirmation were 0.05-0.5 ng/mL and 0.05-1 ng/mL, respectively.