Human nutritional supplements in the horse. Dehydroepiandrosterone versus androstenedione: comparative effects on the androgen profile and consequences for doping analysis.

This study investigates the impact of nutritional supplements dehydroepiandrosterone (DHEA) and androstenedione, both weak androgens, on the androgen profile in horses when given orally, and how that impacts doping analysis. The study finds that the supplements result in a brief peak in testosterone and quick renal clearance, limiting the detection period. Furthermore, it suggests some possible masking effects in doping tests and outlines additional markers.

Research Context

• The research is set on the context of nutritional supplementation in horses, specifically focusing on dehydroepiandrosterone (DHEA) and androstenedione, both of which are classified as weak androgens.
• These substances require conversion to a more potent hormone, testosterone, which has anabolic effects – promoting muscle and bone growth.

Research Methodology

• The researchers administered oral doses of 1 mg/kg of the substances to mares and geldings (female and male horses).
• They then assessed the impact of these doses on the urinary and plasma androgen profile of the horses using an analytical method that included conjugate fractionation and selective hydrolysis, group separation, and quantification through gas chromatography-mass spectrometry.

Primary Outcomes

• The study found that peak testosterone levels in urine were achieved several hours after dosing; these peak levels ranged from 300-6000 micrograms per litre.
• Prompt renal clearance was observed, meaning that the detectable period for the increased testosterone was relatively short – lasting only 20 to 33 hours.
• The longest detection period was observed for androstenedione.

Additional Findings

• The researchers noted that the usual ratio used for detecting exogenous (externally sourced) testosterone in mares was ineffective after DHEA administration, due to a coinciding increase of epitestosterone, which seemed to act as a masking agent.
• Further markers were identified in the form of androstanediols, androstenediols, and certain 17-ketosteroids.
• Finally, the study evidenced a temporary increase in circulating free testosterone, suggesting a possible anabolic/androgenic action when supplementing with DHEA and androstenedione orally.

Implications on Doping Analysis

• Findings from the study could have significant implications for doping analysis procedures in equine sports.
• The rapid renal clearance and short detection period for testosterone would require testing to occur promptly after suspected administration while the increase in epitestosterone could cause a masking effect in standard tests for exogenous testosterone.
• The identification of additional markers could, however, offer alternative means of detection.