Effects of nandrolone phenylpropionate in the horse: (1) resting animal.

This research studies the impact of an anabolic steroid, nandrolone phenylpropionate, on horses. Though it expectedly had some influence on behavior, it did not register consistent anabolic effects.

Objective and Method of Study

• The study aimed to investigate the effects of nandrolone phenylpropionate, an anabolic steroid, on horses. This was carried out by administering seven weekly injections of the said substance (400 mg dosage) on four mature and healthy geldings (castrated male horses).

Assessments and Measurements

• The researchers took various measures to evaluate the impact of the steroid injections. These included monitoring the horses’ body weight, assessing nitrogen retention, and examining plasma urea levels. However, these parameters failed to demonstrate a consistent anabolic effect.
• Muscle biopsies from the semitendinosus and biceps femoris muscles were also conducted to investigate potential alterations induced by the treatment. Specifically, they examined any changes in water content or glycogen concentration; no changes were observed.
• The researchers examined the activities of six muscle enzymes but found no changes here either.
• The only noticeable change was a significant increase in the proportion of fast twitch low oxidative fibers in the biceps femoris muscle. Fast twitch fibers are primarily responsible for speed and power in muscle movements.

Plasma Biochemical Analysis & Behavioral Changes

• The treatment’s effects on a broad array of plasma biochemical constituents were investigated, likely to discover any physiological changes that may not visibly manifest but could affect the general well-being of the horses.
• The research also noted that some instances of stallion-like behavior were observed in the geldings. These behavioral changes were interpreted as an indication of residual androgenic activity from the steroid compound. This is noteworthy because geldings, being castrated male horses, are typically docile and lack the aggressive behaviors associated with intact stallions.

Conclusion

• While some behavioral changes were recorded, the use of the anabolic steroid nandrolone phenylpropionate did not demonstrate consistent anabolic effects or any significant physiological changes in the horses. More research may be necessary to substantiate its effects or lack thereof.