Study summary · research use only
Qualitative identification of growth hormone-releasing hormones in human plasma by means of immunoaffinity purification and LC-HRMS/MS
Plain-language summary
Paraphrased from the published abstract below — not a verdict on whether anything works.
This study describes a method to detect four growth hormone-releasing hormones (GHRHs) and metabolites in human plasma via immunoaffinity purification and mass spectrometry. Target analytes were Geref (Sermorelin), CJC-1293, CJC-1295, and Egrifta (Tesamorelin), plus two metabolites of Geref and CJC-1293. Validation showed recovery of 19-37%, a lower limit of detection below 50 pg/mL, and imprecision below 20%. Rats received intravenous administration of one GHRH compound each, with blood sampled 2, 4, and 8 h later; intact substances were detected for at least 4 h, and no anticipated metabolite was confirmed in rat samples. A Geref metabolite (GHRH3-29) was found in a human plasma sample after subcutaneous injection. The authors state the method can be applied to sports drug testing samples.
Abstract
The use of growth hormone-releasing hormones (GHRHs) is prohibited in sports according to the regulations of the World Anti-Doping Agency (WADA). The aim of the present study was to develop a method for the simultaneous detection of four different GHRHs and respective metabolites from human plasma by means of immunoaffinity purification and subsequent nano-ultrahigh performance liquid chromatography-high resolution/high accuracy (tandem) mass spectrometry. The target analytes included Geref (Sermorelin), CJC-1293, CJC-1295, and Egrifta (Tesamorelin) as well as two metabolites of Geref and CJC-1293, which were captured from plasma samples using a polyclonal GHRH antibody in concert with protein A/G monolithic MSIA™ D.A.R.T.'S® (Disposable Automation Research Tips) prior to separation and detection. The method was fully validated and found to be fit for purpose considering the parameters specificity, linearity, recovery (19-37%), lower limit of detection (<50 pg/mL), imprecision (<20%), and ion suppression/enhancement effects. The analytes' stability and metabolism were elucidated using in vitro and in vivo approaches. EDTA blood samples were collected from rats 2, 4, and 8 h after intravenous administration of GHRH (one compound per test animal). All intact substances were detected for at least 4 h but no anticipated metabolite was confirmed in laboratory rodents' samples; conversely, a Geref metabolite (GHRH3-29) was found in a human plasma sample collected after subcutaneous injection of the drug to a healthy male volunteer. The obtained results demonstrate that GHRHs are successfully detected in plasma using an immunoaffinity-mass spectrometry-based method, which can be applied to sports drug testing samples. Further studies are however required and warranted to account for potential species-related differences in metabolism and elimination of the target analytes.
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