Characterization and detection of growth hormone releasing peptides and their metabolites using in-vitro and in-vivo approaches

Code: 10D5MT

Besides the widely assumed misuse of growth hormone as performance enhancing drug, a new class of compounds has received much interest in doping controls. Recent findings of growth hormone releasing peptides (GHRP) in nutritional supplements have shown the urgency to develop detection methods for these substances. To date the knowledge of the metabolic fate of these agents after oral application are only barely described. In the planned study different GHRPs will be synthesized, chemically characterized by liquid chromatography and mass spectrometry and metabolic products will be identified after in-vitro metabolism and animal feeding experiments. Finally, these metabolites will also be synthesized and a sensitive determination method by means of LC-MS/MS will be established.

Main Findings

The obtained data allow the implementation of metabolic products of a variety of GHRPs into routine doping controls. Although derived from animal in-vivo studies, the model appears valid in a qualitative manner since human in-vitro incubations corroborated the likely presence of the surrogate in-vivo generated compounds in human urine. The obtained results will be published in the near future and all data are available for doping control laboratories to implement a facile LC-MS/MS-based procedure for these prohibited compounds by means of commonly and routinely employed instrumental equipment (triple quadrupole mass spectrometers or equivalent). Furthermore, with the same procedure it is also possible to determine additional prohibited peptides in urine (e.g. desmopressin, gonadorelin) and, thus, the method provides the option to implement a screening for different compound instead of an assay limited to individual compounds only. Up to now the collected blood samples from the in-vivo experiments are not analysed. Here it would be interesting to develop a sophisticated purification procedure to detect the target analytes also in blood. This is of particular interest as doping control tests for hGH are conducted with serum. In case of atypically high amounts of endogenous hGH, the same sample can/should be analysed for the presence of these releasing peptides.