Determination of growth hormone secretagogue pralmorelin (GHRP-2) and its metabolite in human urine by liquid chromatography/electrospray ionization tandem mass spectrometry.
GHRP-2 (pralmorelin, D-Ala-D-(beta-naphthyl)-Ala-Ala-Trp-D-Phe-Lys-NH(2)), which belongs to a class of growth hormone secretagogue (GHS), is intravenously used to diagnose growth hormone (GH) deficiency. Because it may be misused in expectation of a growth-promoting effect by athletes, the illicit use of GHS by athletes has been prohibited by the World Anti-Doping Agency (WADA). Therefore, the mass spectrometric identification of urinary GHRP-2 and its metabolite D-Ala-D-(beta-naphthyl)-Ala-Ala-OH (AA-3) was studied using liquid chromatography/electrospray ionization tandem mass spectrometry for doping control purposes. The method consists of solid-phase extraction using stable-isotope-labeled GHRP-2 as an internal standard and subsequent ultra-performance liquid chromatography/tandem mass spectrometry, and the two target peptides were determined at urinary concentrations of 0.5-10 ng/mL. The recoveries ranged from 84 to 101%, and the assay precisions were calculated as 1.6-3.8% (intra-day) and 1.9-4.3% (inter-day). Intravenous administration of GHRP-2 in ten male volunteers was studied to demonstrate the applicability of the method. In all ten cases, unchanged GHRP-2 and its specific metabolite AA-3 were detected in urine.
Okano
Masato
M
Anti-Doping Center, Mitsubishi Chemical Medience Corporation, Tokyo, Japan. Okano.Masato@mk.medience.co.jp
Sato
Mitsuhiko
M
Ikekita
Ayako
A
Kageyama
Shinji
S
D000328:Adult; D002851:Chromatography, High Pressure Liquid / Q000379:methods*; D002853:Chromatography, Liquid / Q000379:methods*; D006801:Humans; D008297:Male; D009842:Oligopeptides / Q000378:metabolism* / Q000652:urine*; D021241:Spectrometry, Mass, Electrospray Ionization / Q000379:methods*; D055815:Young Adult
D009842:Oligopeptides; C091874:growth hormone-releasing peptide-2