Effects of nandrolone phenylpropionate in the horse: (2) general effects in animals undergoing training.

The research article discusses a study where researchers examined the effects of weekly injections of a steroid, nandrolone phenylpropionate, on Thoroughbred geldings during two training periods. The study found no significant performance improvements resulting from the steroid administration.

Study Method

• The researchers used a crossover trial model with two training periods. This meant that the same group of horses underwent both training periods, with and without the steroid injections. This method helps to ensure that any observed differences can be reliably attributed to the experimental treatment.
• Nandrolone phenylpropionate, an anabolic steroid, was administered to the horses in 11 weekly injections with each injection containing 400 mg of the steroid.
• The trial involved 6 Thoroughbred geldings, i.e., male horses that have been gelded.

Findings

• The researchers found a decrease in body weight and flank measurement, but this effect was only observed during the first training period and was not influenced by the steroid.
• Lower urinary nitrogen excretion was also observed in the steroid-treated horses during the first training period only.
• No significant changes were found in blood biochemistry or haematology due to either training or steroid administration. This suggests that neither training nor steroid use changed the horses’ blood profile in a statistically significant way.
• Independent of the treatment, a decrease in plasma chloride levels and an increase in haematocrit took place during the latter, more intensive anaerobic training period in the crossover trial. Haematocrit refers to the portion of blood volume that is made up of red blood cells, and its elevation typically indicates an increase in the body’s oxygen-carrying capacity.
• No alterations were observed in urinary pH or specific gravity throughout the research. These measures relate to urine concentration and the balance between acidity and alkalinity.
• Importantly, no evidence of improved racing performance due to nandrolone phenylpropionate administration was observed. This finding is particularly significant as it questions the efficacy of such steroid use in sports.
• The study also found that behavioral changes that could be attributed to the use of nandrolone phenylpropionate persisted for at least 6 weeks after the treatment was stopped.