Analysis of new growth promoting black market products.
Growth hormone & IGF research : official journal of the Growth Hormone Research Society and the International IGF Research Society
confidence
Key findings
Analytical identification of modified GH (22,195 Da) and GHRP analogues (Gly-GHRP-6, Gly-GHRP-2, Gly-Ipamorelin) in black market products; no clinical/biological endpoints.
View source on PubMed (PMID 29864719) ↗
- Sample size
- Not reported
- Population
- Not applicable (analytical study of black market products)
- Dosing
- Not reported
- Duration
- Not reported
- Route
- Not reported
- Blinding
- not_reported
- Controls
- not_reported
- Drug class
- peptide
Full abstract
Detecting agents allegedly or evidently promoting growth such as human growth hormone (GH) or growth hormone releasing peptides (GHRP) in doping controls has represented a pressing issue for sports drug testing laboratories. While GH is a recombinant protein with a molecular weight of 22 kDa, the GHRPs are short (3-6 amino acids long) peptides with GH releasing properties. The endogenously produced GH (22 kDa isoform) consists of 191 amino acids and has a monoisotopic molecular mass of 22,124 Da. Within this study, a slightly modified form of GH was discovered consisting of 192 amino acids carrying an additional alanine at the N-terminus, leading to a monoisotopic mass of 22,195 Da. This was confirmed by top-down and bottom-up experiments using liquid chromatography coupled to high resolution/high accuracy mass spectrometry. Additionally, three analogues of GHRPs were identified as Gly-GHRP-6, Gly-GHRP-2 and Gly-Ipamorelin, representing the corresponding GHRP extended by a N-terminal glycine residue. The structure of these peptides was characterised by means of high resolution (tandem) mass spectrometry, and for Gly-Ipamorelin and Gly-GHRP-2 their identity was additionally confirmed by custom synthesis. Further, established in-vitro experiments provided preliminary information considering the potential metabolism after administration.