Plasma growth hormone (GH) responses after administration of the peptidergic GH secretagogue KP102 into the oral cavity, rumen, abomasum and duodenum in adult goats

Hashizume, Takumi; Tanabe, Yuji; Ohtsuki, K; Mori, Ayaka; Matsumoto, N; Hara, Shigeo

doi:10.1016/s0739-7240(00)00087-4

Cited by 5 publications

(3 citation statements)

References 24 publications

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“…Due to their low molecular mass (<1000 Da), GHRPs are bioavailable after intravenous, subcutaneous, intranasal, buccal, and in some cases also oral (iv, sc, in, b, po) administration and increase age-related the amount of hGH and insulin-like growth factor-1 (IGF-1) in the treated individuals independently from gender. − Due to their variable bioavailability and application routes, their metabolic fate is expected to be extensive. Consequently, the knowledge of metabolic pathways is of utmost importance for effective doping control procedures as the search for unmodified target analytes in urine was described to be insufficient …”

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confidence: 99%

Metabolism of Growth Hormone Releasing Peptides

et al. 2012

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New, potentially performance enhancing compounds have frequently been introduced to licit and illicit markets and rapidly distributed via worldwide operating Internet platforms. Developing fast analytical strategies to follow these new trends is one the most challenging issues for modern doping control analysis. Even if reference compounds for the active drugs are readily obtained, their unknown metabolism complicates effective testing strategies. Recently, a new class of small C-terminally amidated peptides comprising four to seven amino acid residues received considerable attention of sports drug testing authorities due to their ability to stimulate growth hormone release from the pituitary. The most promising candidates are the growth hormone releasing peptide (GHRP)-1, -2, -4, -5, -6, hexarelin, alexamorelin, and ipamorelin. With the exemption of GHRP-2, the entity of these peptides represents nonapproved pharmaceuticals; however, via Internet providers, all compounds are readily available. To date, only limited information on the metabolism of these substances is available and merely one metabolite for GHRP-2 is established. Therefore, a comprehensive in vivo (po and iv administration in rats) and in vitro (with human serum and recombinant amidase) study was performed in order to generate information on urinary metabolites potentially useful for routine doping controls. The urine samples from the in vivo experiments were purified by mixed-mode cation-exchange solid-phase extraction and analyzed by ultrahigh-performance liquid chromatography (UHPLC) separation followed by high-resolution/high-accuracy mass spectrometry. Combining the high resolution power of a benchtop Orbitrap mass analyzer for the first metabolite screening and the speed of a quadrupole/time-of-flight (Q-TOF) instrument for identification, urinary metabolites were screened by means of a sensitive full scan analysis and subsequently confirmed by high-accuracy product ion scan experiments. Two deuterium-labeled internal standards (triply deuterated GHRP-4 and GHRP-2 metabolite) were used to optimize the extraction and analysis procedure. Overall, 28 metabolites (at least three for each GHRP) were identified from the in vivo samples and main metabolites were confirmed by the human in vitro model. All identified metabolites were formed due to exopeptidase- (amino- or carboxy-), amidase-, or endopeptidase activity.

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confidence: 99%

Metabolism of Growth Hormone Releasing Peptides

et al. 2012

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“…Nevertheless, the impact of such peptides on poultry productivity is still not fully investigated, and more information is still necessary. Synthetic GH secretagogues (GHSs) or GH-releasing peptides (GHRP) comprise synthetic peptides that have potent GH-boosting properties and effectively mimic the influence of endogenous GH and, in turn, stimulate animal growth [9,13]. In various mammalian species, the administration of GHSs has been shown to promote feed intake (FI) [9,[13][14][15][16].…”

Section: Introductionmentioning

confidence: 99%

“…Synthetic GH secretagogues (GHSs) or GH-releasing peptides (GHRP) comprise synthetic peptides that have potent GH-boosting properties and effectively mimic the influence of endogenous GH and, in turn, stimulate animal growth [9,13]. In various mammalian species, the administration of GHSs has been shown to promote feed intake (FI) [9,[13][14][15][16]. However, earlier research in neonatal chicks showed that GHRP-6 injection suppressed FI but not feed retention [17].…”

Section: Introductionmentioning

confidence: 99%

Promising Role of Growth Hormone-Boosting Peptide in Regulating the Expression of Muscle-Specific Genes and Related MicroRNAs in Broiler Chickens

Ibrahim

Al-Khalaifah

Abdelfattah‐Hassan

et al. 2021

Animals

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Appropriate skeletal muscle development in poultry is positively related to increasing its meat production. Synthetic peptides with growth hormone-boosting properties can intensify the effects of endogenous growth hormones. However, their effects on the mRNA and miRNA expression profiles that control muscle development post-hatching in broiler chicks is unclear. Thus, we evaluated the possible effects of synthetic growth hormone-boosting peptide (GHBP) inclusion on a chicken’s growth rate, skeletal muscle development-related genes and myomiRs, serum biochemical parameters, and myofiber characteristics. A total of 400 one-day-old broiler chicks were divided into four groups supplied with GHBP at the levels of 0, 100, 200 and 300 μg/kg for 7 days post-hatching. The results showed that the highest levels of serum IGF-1 and GH at d 20 and d 38 post-hatching were found in the 200 μg/kg GHBP group. Targeted gene expression analysis in skeletal muscle revealed that the GHBP effect was more prominent at d 20 post-hatching. The maximum muscle development in the 200 μg/kg GHBP group was fostered by the upregulation of IGF-1, mTOR, myoD, and myogenin and the downregulation of myostatin and the Pax-3 and -7 genes compared to the control group. In parallel, muscle-specific myomiR analysis described upregulation of miR-27b and miR-499 and down-regulation of miR-1a, miR-133a, miR-133b, and miR-206 in both the 200 and 300 μg/kg GHBP groups. This was reflected in the weight gain of birds, which was increased by 17.3 and 11.2% in the 200 and 300 μg/kg GHBP groups, respectively, when compared with the control group. Moreover, the maximum improvement in the feed conversion ratio was achieved in the 200 μg/kg GHBP group. The myogenic effects of GHBP were also confirmed via studying myofiber characteristics, wherein the largest myofiber sizes and areas were achieved in the 200 μg/kg GHBP group. Overall, our findings indicated that administration of 200 μg/kg GHBP for broiler chicks could accelerate their muscle development by positively regulating muscle-specific mRNA and myomiR expression and reinforcing myofiber growth.

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Identification of the growth‐hormone‐releasing peptide‐2 (GHRP‐2) in a nutritional supplement

Thomas¹,

Kohler²,

Mester³

et al. 2010

Drug Testing and Analysis

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Black market products of a pharmaceutical nature and nutritional supplements have received substantial and increasing attention because of potential performance enhancement in elite and non-professional sports. In addition, improved general health is claimed for non-competing individuals. The risks and foreseeable dangers of the uncontrolled use of highly potent and non-approved pharmaceutical compounds in healthy individuals are of considerable concern. In the present case report, the emerging drug candidate GHRP-2 with verified growth-hormone-releasing properties was identified and quantified in tablets offered as an over-the-counter nutritional supplement. The impact of this orally active peptide on the hGH/IGF-axis has been established for several years and its illicit use in elite sports has been assumed. As a releasing factor for hGH, GHRP-2 belongs to the list of substances prohibited by the World Anti-Doping Agency (WADA). Unfortunately, to date there is no routinely performed assay for the determination of these peptides potentially occurring in biological fluids of competing athletes, but the present data will facilitate the implementation by providing principle analytical information on liquid chromatographic and mass spectrometric behaviour. Qualitative identification of the target analyte after extraction from the tablet matrix was performed by high resolution/high accuracy mass spectrometry after liquid chromatographic separation under consideration of the accurate masses and the ratios of the protonated molecules and their fragment ions derived from their collisionally induced dissociation. Quantitative results were obtained by means of liquid chromatography coupled to a triple quadrupole mass spectrometer and linear regression using an external calibration curve (with GHRP-2 reference compound) adjusted via internal standard (Hexarelin). Hereby, the content of GHRP-2 was determined with approximately 50 µg per tablet.

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Plasma growth hormone (GH) responses after administration of the peptidergic GH secretagogue KP102 into the oral cavity, rumen, abomasum and duodenum in adult goats

Cited by 5 publications

References 24 publications

Metabolism of Growth Hormone Releasing Peptides

Metabolism of Growth Hormone Releasing Peptides

Promising Role of Growth Hormone-Boosting Peptide in Regulating the Expression of Muscle-Specific Genes and Related MicroRNAs in Broiler Chickens

Identification of the growth‐hormone‐releasing peptide‐2 (GHRP‐2) in a nutritional supplement

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