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

The effect of 11 weekly injections of nandrolone phenylpropionate (400 mg) was investigated by a crossover trial (2 training periods) in 6 Thoroughbred geldings undergoing training. A decrease in body weight and flank measurement occurred only during the first training period and was not modified by the anabolic steroid. Urinary nitrogen excretion was lower in the anabolic treated animals only in the first training period. Neither training nor training plus nandrolone phenylpropionate administration caused any marked alteration in blood biochemistry or haematology. A significant decrease in plasma chloride and increase in haematocrit occurred independent of treatment in the latter, more extensive anaerobic training of both parts of the crossover. No change in urinary pH or specific gravity was found throughout the study. No evidence of improved racing performance due to nandrolone phenylpropionate administration was observed. Behavioural changes attributed to the drug could be detected for at least 6 weeks after the cessation of treatment.