Nandrolone decanoate has long-term effects on dominance in a competitive situation in male rats

The aim of the present study was to examine possible long-term effects of the anabolic androgenic steroid (AAS), nandrolone decanoate (ND), on dominance in a provoking and competitive situation in sexually matured male rats. The experimental group (n=10) received daily injections of ND [15 mg/kg in a volume of 1 ml/kg subcutaneous (s.c.) injection for 14 days]. During the corresponding period, the controls (n=10) were given daily injections of an oil vehicle (1 ml/kg s.c.). All animals were tested in a competitive situation at four occasions after the end of the treatment period (week 5, 8, 11 and 14). Water-deprived pairs of rats, consisting of one ND-treated rat and one control, had to compete for access to water. The results showed that the ND-treated rats approached the water spout significantly more often compared to the controls. During the competition tests, the ND-treated rats spent more time drinking, an effect that was prominent for 11 weeks after the end of the treatment period. The ND-treated rats also displayed more frequently piloerection than the controls. The results indicate that ND has long-term effect on dominance in a provoking and competitive situation.