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Identification of gonadotropin‐releasing hormone metabolites in greyhound urine
Author(s) -
Palmer David,
Rademaker Katie,
Martin Ingrid,
Hessell Joan,
Howitt Rob
Publication year - 2017
Publication title -
drug testing and analysis
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.065
H-Index - 54
eISSN - 1942-7611
pISSN - 1942-7603
DOI - 10.1002/dta.2164
Subject(s) - luteinizing hormone , gonadotropin releasing hormone , endocrinology , urine , medicine , testosterone (patch) , hormone , kisspeptin , gonadotropin , chemistry
Gonadotropin‐releasing hormone (GnRH) is a 10‐residue peptide hormone that induces secretion of luteinizing hormone (LH) and follicle‐stimulating hormone into the blood from the pituitary gland. In males, LH acts on the testes to produce testosterone. The performance‐enhancing potential of testosterone makes administration of exogenous GnRH a concern in sports doping control. Detection of GnRH abuse is challenging owing to its rapid clearance from the body and its degradation in urine. Following recent investigations of GnRH abuse in racing greyhounds in New Zealand, we carried out a GnRH administration study in greyhounds in an attempt to identify GnRH metabolites that might provide more facile detection of GnRH abuse; little information is available on in vivo metabolites of exogenous GnRH in any species and none in dogs. We identified three C‐terminal GnRH metabolites in urine: GnRH 5–10, GnRH 6–10, and GnRH 7–10. These metabolites and intact GnRH, which was also detected in urine, were all excreted over a 1–3 h period after GnRH administration. Two of the GnRH metabolites – GnRH 5–10 and GnRH 6–10 – were more stable in urine than intact GnRH offering improved potential to detect GnRH administration. Copyright © 2017 John Wiley & Sons, Ltd.