Hydrocortisone concentrations in post-race urine from horses.
Abstract: As hydrocortisone is an endogenous substance, it is first necessary to establish its normal concentrations so as to be able to control its use in racing animals. This study was designed to establish the hydrocortisone concentrations in post-race urine samples of horses racing in Brazil and also to evaluate the results in relation to the international threshold set for this drug. Urine samples were analysed by HPLC-UV. The results were evaluated according to the concentration range as well as sex and time of sample collection (afternoon or evening races). The results showed a high degree of variation in the concentrations of hydrocortisone in the urine (93 +/- 69 ng/ml). The maximum concentration observed was 646 ng/ml, although only a few horses (around 1%) showed levels within the range 500-650 ng/ml, 91% being in the range 0-150 ng/ml. The data suggested a normal distribution curve. Statistical analysis showed no significant influence of sex or time of sample collection.
Publication Date: 2000-06-03 PubMed ID: 10836269DOI: 10.1023/a:1006446832599Google Scholar: Lookup
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Summary
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The research focuses on evaluating the concentration of hydrocortisone in urine samples of race horses in Brazil, following a race, to establish a normal range for this substance and compare it against an international threshold.
Establishing Normal Hydrocortisone Concentrations in Horses
- The study seeks to establish a standard range for the concentrations of hydrocortisone, a naturally occurring substance, in race horses’ post-race urine. This knowledge is crucial in regulating the use of this substance in racing animals.
- Utilizing a method known as High-Performance Liquid Chromatography with Ultraviolet detection (HPLC-UV), the research team analyzed urine samples gathered from the horses. The HPLC-UV technique allows for the separation, identification, and quantification of the components in the urine samples, in this case, hydrocortisone.
- Given the endogenous nature of hydrocortisone (meaning it’s produced within the body), researchers endeavored to discern what a typical concentration would be in horses naturally, specifically following a race.
Variations in Hydrocortisone Concentrations and Influencing Factors
- The outcomes exhibited a significant variance in the concentration levels of hydrocortisone. The standard deviation was around 69 ng/ml, with an average concentration of 93 ng/ml. Hydrocortisone concentrations ranged broadly, with the peak concentration recorded being 646 ng/ml.
- However, the bulk of horses (about 91%) had hydrocortisone levels within a lower range of 0-150 ng/ml. Only about 1% of the horses had levels that hit the upper range of 500-650 ng/ml.
- Statistically, the concentration data followed a curve that suggested a normal distribution, indicating that most of the results were clustered around the mean, with fewer results appearing as the values deviate further from the mean.
- Interestingly, the research found no substantial influence of factors such as sex or the time of the sample collection (i.e., whether the race occurred in the afternoon or the evening) on the concentration of hydrocortisone.
Implications for Substance Regulation in Horse Racing
- The study’s findings are essential for comparing the normal concentrations of hydrocortisone to the currently set international threshold for this substance, thereby governing its usage in horses participating in races.
- This kind of understanding provides insights into potential over-use or misuse of performance enhancing methods in horse racing.
Cite This Article
APA
Ribeiro Neto LM, Salvadori MC, Spinosa HS.
(2000).
Hydrocortisone concentrations in post-race urine from horses.
Vet Res Commun, 24(4), 239-244.
https://doi.org/10.1023/a:1006446832599 Publication
Researcher Affiliations
- Department of Antidoping Control, Jockey Club of São Paulo, SP, Brazil.
MeSH Terms
- Animals
- Brazil
- Chromatography, High Pressure Liquid / veterinary
- Female
- Horses / urine
- Hydrocortisone / urine
- Male
- Running
- Sports
References
This article includes 4 references
- Ralston JM, Stenhouse AM, Stenhouse NS, Buck GJ, Lucks SF, Reynoldson JA, Bolton JR. Cortisol concentrations in blood and urine of horses.. Aust Vet J 1988 Jan;65(1):1-5.
- Toutain PL, Oukessou M, Autefage A, Alvinerie M. Diurnal and episodic variations of plasma hydrocortisone concentrations in horses.. Domest Anim Endocrinol 1988 Jan;5(1):55-9.
- Popot MA, Houghton E, Ginn A, Jones M, Teale P, Samuels T, Lassourd V, Dunnett N, Cowan DA, Bonnaire Y, Toutain PL. Cortisol concentrations in post competition horse urine: a French and British survey.. Equine Vet J 1997 May;29(3):226-9.
- Ribeiro Neto LM, Spinosa HS, Salvadori MC. The use of ELISA tests and immunoaffinity chromatography combined with reversed-phase high-performance liquid chromatography for dexamethasone detection in equine urine.. J Anal Toxicol 1997 Sep;21(5):393-6.
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