A test able to detect even the smallest amount of insulin in horse urine has recently been developed to aid in the detection of insulin doping in racehorses, according to a group of researchers from the Hong Kong Jockey Club's Racing laboratory.
Insulin, a hormone produced by the pancreas, is primarily used to treat patients with diabetes mellitus. Because horses are rarely diagnosed with this condition, there currently are no pharmaceutical grades of equine insulin commercially available. Thus, affected horses are administered unapproved forms of insulin, including human, pig, and cow insulin as well as synthetic forms.
Because of insulin's ability to build muscle and improve endurance, the practice of illegally administering insulin to racehorses has become more common.
Scot Waterman, DVM, executive director and chief operating officer of the Racing and Medication & Testing Consortium in Lexington, Ky., said, "Anything that isn't expressly permitted by rule is prohibited (in racing). Insulin is not permitted so a lab finding would be a violation."
Hong Kong Jockey Club researchers recently tested nano liquid chromatography-tandem mass spectrometry for its efficacy in detecting insulin in horse urine as a method of drug testing.
In this laboratory technique, individual ingredients in a liquid sample (in this case horse urine) are separated in a tiny tube (called a liquid chromatography column). As the ingredients are separated, their chemical composition is analyzed by mass spectrometry, and each individual ingredient can be identified by comparing the chemical compounds to a database. This is a rapid, reliable technique widely used in other forms of drug testing.
Using this technique, the team was able to positively detect human insulin in urine samples collected from two horses administered a single 10 IU (international units) dose of the insulin Humulin R up to four hours after administration. According to the study authors, this test provides "direct proof of the applicability of urine doping control testing of insulin in horses."
According to Waterman, this new test would be a suitable addition to the U.S. racing community: "Any new method to detect potential doping substances is always a welcome occurrence."
The study, "Doping control analysis of insulin and its analogues in equine urine by liquid chromatography-tandem mass spectrometry," was published in February 2001 in the Journal of Chromatography. The abstract is available on PubMed.
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