Study summary · research use only
Detection of the growth hormone secretagogue MK-0677 in equine hair following oral administration
Plain-language summary
Paraphrased from the published abstract below — not a verdict on whether anything works.
In this study using a Thoroughbred racehorse, researchers investigated whether MK-0677 (ibutamoren), an orally active non-peptide growth hormone secretagogue, could be detected in equine hair following oral administration of MK-0677 mesylate. MK-0677 and its O-dealkylated metabolite were extracted from hair using an existing method for prohibited substances and analysed by liquid chromatography tandem mass spectrometry. MK-0677 was detected in all hair samples collected, up to 209 days in mane and 358 days in tail; a follow-up method with an extensive wash procedure confirmed its presence. Wash criteria distinguishing internal incorporation (via bloodstream) from external deposition (via sweat and sebum) indicated internal incorporation for samples collected at later time points (52 days or more) and a combination of both routes for samples collected at 2 days.
Abstract
MK-0677 (ibutamoren) is an orally active non-peptide growth hormone secretagogue that binds to the ghrelin receptor stimulating the secretion of endogenous growth hormone. It is one of the most prevalent performance-enhancing compounds currently available online and is potentially subject to abuse both in human and equine sports. The aim of the current study was to investigate whether it could be detected in equine hair following oral administration of MK-0677 mesylate to a Thoroughbred racehorse. MK-0677 and its O-dealkylated metabolite were extracted using an existing method for prohibited substances in equine hair and analysed by liquid chromatography tandem mass spectrometry. This enabled the detection of MK-0677 in all hair samples collected, up to 209 days in mane and 358 days in tail. A follow-up methodology with an extensive wash procedure was carried out for selected hair samples, which unambiguously verified the presence of MK-0677. Wash criteria to differentiate between internal incorporation (via bloodstream) and external deposition (via sweat and sebum) was also assessed and indicated internal incorporation for the samples collected at later time points (≥52 days) and a combination of internal incorporation and external deposition for hair samples collected at the earlier time point (2 days).
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