Study summary · research use only
Analysis of new growth promoting black market products
Plain-language summary
Paraphrased from the published abstract below — not a verdict on whether anything works.
This laboratory/analytical study (species not specified) examined black market products for growth-hormone-related doping and identified a modified form of growth hormone (GH) and analogs of growth hormone releasing peptides (GHRP) using liquid chromatography coupled to high resolution/high accuracy mass spectrometry. Endogenous GH (22 kDa isoform) consists of 191 amino acids with a monoisotopic mass of 22,124 Da; the study identified a modified GH form of 192 amino acids with an additional N-terminal alanine, mass 22,195 Da, confirmed by top-down and bottom-up experiments. Three GHRP analogues were identified as Gly-GHRP-6, Gly-GHRP-2, and Gly-Ipamorelin, each the corresponding GHRP extended by an N-terminal glycine, characterized by high resolution (tandem) mass spectrometry and, for Gly-Ipamorelin and Gly-GHRP-2, custom synthesis; in-vitro experiments gave preliminary metabolism information.
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.
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