Residues of nortestosterone esters at injection sites. Part 2. Behaviouraleffects

Anecdotal evidence in man suggests that abuse of anabolic androgenic steroi ds (AAS) is linked with increased aggression. In order to test the hypothes is that administration of nortestosterone (beta-NT) esters may increase agg ression, behavioural effects following beta-NT phenylpropionate (NTPP) admi nistration were assessed in male mice using the isolation-induced aggressio n paradigm. Mice (n = 80) were individually caged and randomly assigned to 'resident' or 'intruder' status. Residents received one of four treatments: subcutaneous (s/c) injection of oil of arachis (OILINJ), s/c injection of NTPP in oil of arachis (NTINJ), oil of arachis per os (OILOS) and NTPP in o il of arachis per os (NTOS). After treatment, weight-matched intruders were introduced into each resident's cage and the encounter was videotaped to a llow the frequency (f) and duration (d) of social, non-social, offensive an d defensive behaviours displayed by residents and intruders to be measured. The latency of bite attack for residents was significantly shorter in NTOS compared to OILOS. There was no difference in either f or d of aggressive behaviours between NTINJ and OILINJ. Because OILINJ residents demonstrated similar levels of aggression to NTOS, it is possible that the aggression in NTOS mice may be mediated by a different biochemical pathway. Extrapolatio n of these results indicate that ingestion of beta-NT esters may have a rol e in the induction of aggression in consumers.