Evidence of boldenone, nandrolone, 5(10)-estrene-3β-17α-diol and 4-estrene-3,17-dione as minor metabolites of testosterone in equine.

The detection of boldenone, nandrolone, 5(10)-estrene-3β,17α-diol, and 4-estrene-3,17-dione in a urine sample collected from a gelding having been treated with testosterone (500 mg 'Testosterone Suspension 100', single dose, injected intramuscularly) in 2009 led the authors' laboratory to suspect that these 'testicular' steroids could be minor metabolites of testosterone in geldings. Administration trials on six castrated horses with Testosterone Suspension 100 confirmed that low levels of boldenone, nandrolone, 5(10)-estrene-3β,17α-diol, and 4-estrene-3,17-dione could indeed be detected and confirmed in the early post-administration urine samples from all six geldings. Although boldenone has been reported to be present in urine after testosterone administration, there has been no direct evidence reported that boldenone, nandrolone, 5(10)-estrene-3β,17α-diol, and 4-estrene-3,17-dione are metabolites of testosterone in geldings.

Metabolic studies of oxyguno in horses.

Oxyguno (4-chloro-17α-methyl-17β-hydroxy-androst-4-ene-3,11-dione) is a synthetic oral anabolic androgenic steroid commercially available without a prescription. Manufacturers of oxyguno claim that its anabolic effect in metabolic enhancement exceeds that of the classic anabolic steroid testosterone by seven times, but its androgenic side-effects are only twelve percent of testosterone. Like other anabolic androgenic steroids, oxyguno is prohibited in equine sports.

Liquid chromatography-mass spectrometry analysis of five bisphosphonates in equine urine and plasma.

Bisphosphonates are used in the management of skeletal disorder in humans and horses, with tiludronic acid being the first licensed veterinary medicine in the treatment of lameness associated with degenerative joint disease. Bisphosphonates are prohibited in horseracing according to Article 6 of the International Agreement on Breeding, Racing and Wagering (published by the International Federation of Horseracing Authorities). In order to control the use of bisphosphonates in equine sports, an effective method to detect the use of bisphosphonates is required.

Doping control analysis of filgrastim in equine plasma and its application to a co-administration study of filgrastim and recombinant human erythropoietin in the horse.

Granulocyte colony-stimulating factor (G-CSF) is a hematopoietic growth factor regulating granulopoiesis. The recombinant human granulocyte colony-stimulating factor (rhG-CSF) is widely used for the treatment of granulopenia in humans. Filgrastim is a rhG-CSF analogue and is marketed under various brand names, including Neupogen(®) (Amgen), Imumax(®) (Abbott Laboratories), Neukine(®) (Intas Biopharmaceuticals) and others.

Metabolic studies of formestane in horses.

Formestane (4-hydroxyandrost-4-ene-3,17-dione) is an irreversible steroidal aromatase inhibitor with reported abuse in human sports. In 2011, our laboratory identified the presence of formestane in a horse urine sample from an overseas jurisdiction. This was the first reported case of formestane in a racehorse.

Doping control analysis of TB-500, a synthetic version of an active region of thymosin β₄, in equine urine and plasma by liquid chromatography-mass spectrometry.

A veterinary preparation known as TB-500 and containing a synthetic version of the naturally occurring peptide LKKTETQ has emerged. The peptide segment (17)LKKTETQ(23) is the active site within the protein thymosin β(4) responsible for actin binding, cell migration and wound healing. The key ingredient of TB-500 is the peptide LKKTETQ with artificial acetylation of the N-terminus.

Doping control analysis of insulin and its analogues in equine urine by liquid chromatography-tandem mass spectrometry.

Insulin and its analogues have been banned in both human and equine sports owing to their potential for misuse. Insulin administration can increase muscle glycogen by utilising hyperinsulinaemic clamps prior to sports events or during the recovery phases, and increase muscle size by its chalonic action to inhibit protein breakdown. In order to control insulin abuse in equine sports, a method to effectively detect the use of insulins in horses is required.

Control of the misuse of bromide in horses.

Bromide is a sedative hypnotic. Due to its potential use as a sedative or calmative agent in competition horses, a method to control bromide is needed. Colorimetric method had been employed in the authors' laboratory from 2003 for the semi-quantification of bromide in equine plasma samples.

In vitro and in vivo studies of androst-4-ene-3,6,17-trione in horses by gas chromatography-mass spectrometry.

This paper describes the application of gas chromatography-mass spectrometry (GC-MS) for in vitro and in vivo studies of 6-OXO in horses, with a special aim to identify the most appropriate target metabolite to be monitored for controlling the administration of 6-OXO in racehorses. In vitro studies of 6-OXO were performed using horse liver microsomes. The major biotransformation observed was reduction of one keto group at the C3 or C6 positions.

Doping control analysis of insulin and its analogues in equine plasma by liquid chromatography-tandem mass spectrometry.

Insulin administration can increase muscle glycogen by utilising hyperinsulinaemic clamps prior to sports events or during the recovery phases, and increase muscle size by its chalonic action to inhibit protein breakdown. In order to control insulin abuse in equine sports, a method to detect effectively the use of insulins in horses would be required. Besides the readily available human insulin and its synthetic analogues, structurally similar insulins from other species can also be used as doping agents.

Evaluation of detailed training data to identify risk factors for retirement because of tendon injuries in Thoroughbred racehorses.

Objective: To identify the risk factors for premature retirement because of tendon injury in a Thoroughbred racehorse population.

Animals: 175 Thoroughbred racehorses (cases) at the Hong Kong Jockey Club that were retired from racing because of tendon injury between 1997 and 2004 and for which the last preretirement exercise was at a fast pace were each matched with 3 control horses that were randomly selected from all uninjured horses that had galloped on the same date as that last exercise episode.

Procedures: Training data for all horses were examined.