Intelligence benefit of the 3-methoxytyramine to tyramine ratio in equine urine

Madysen Elbourne; Adam Cawley; Shawn Stanley; Christopher Bowen; Shanlin Fu

doi:10.1002/dta.3264

Intelligence benefit of the 3-methoxytyramine to tyramine ratio in equine urine

Drug Test Anal. 2022 May;14(5):936-942. doi: 10.1002/dta.3264. Epub 2022 Apr 5.

Authors

Madysen Elbourne¹, Adam Cawley², Shawn Stanley³, Christopher Bowen⁴, Shanlin Fu¹

Affiliations

¹ University of Technology Sydney, Sydney, New South Wales, Australia.
² Australian Racing Forensic Laboratory, Racing NSW, Sydney, New South Wales, Australia.
³ Racing Science Centre, Queensland Racing Integrity Commission, Hamilton, Queensland, Australia.
⁴ Shimadzu Scientific Instruments Australasia Pty Ltd, Rydalmere, New South Wales, Australia.

PMID: 35343638
DOI: 10.1002/dta.3264

Abstract

Equine urine analysis has evolved over time to detect thousands of urinary compounds for doping control in the horse racing industry. The longitudinal assessment of 3-methoxytyramine to tyramine ratio (3-MT/T) values in equine urine by GC-MS profiling was investigated to support the Racing NSW Equine Biological Passport (EBP) for detection of dopaminergic manipulation in racehorses. This involved comparison of routine urine samples to administration studies of Sinemet, a common Parkinson's disease medication containing levodopa. Using an endogenous reference compound (ERC) in a urinary ratio enabled greater confidence to provide intelligence of pharmaceutical manipulation as distinct from physiological variation. Population reference limits (PRLs) of 776 ng/ml for urinary 3-MT and 5.3 for 3-MT/T, together with the use of individual reference limits (IRLs), are proposed.

Keywords: 3-methoxytyramine; GC-MS; biomarkers; equine urine; ratio.

MeSH terms

Animals
Dopamine / analogs & derivatives
Doping in Sports*
Horses
Intelligence
Tyramine*
Urinalysis

Substances

3-methoxytyramine
Dopamine
Tyramine