EFFECTS OF CHRONIC TREATMENT WITH TESTOSTERONE PROPIONATE ON AGGRESSION AND HORMONAL LEVELS IN INTACT MALE-MICE

Effects of testosterone propionate, an anabolic-androgenic steroid (AA S), on aggression in gonadally intact male mice were examined. Animals were given weekly injections of 3.75, 7.5, 15, and 30 mg/kg of drug o r sesame oil for 10 weeks. During the last 3 weeks, behavioral tests w ere conducted and at the end of the experiment, body, liver and testes weight and hormonal data were collected. The treatment had minimal be havioral and endocrine effects. It resulted in shorter latencies of 't hreat' only in the last agonistic encounter, increases in testosterone levels and decreases in testes weight in a non-linear dose-dependant way. The action of the treatment was different on threat and attack, t he latter being unaffected. The behavioral effects in the total sample were only found in aggressive animals selected on the basis of their latency of attack in the first encounter. (C) 1998 Elsevier Science Lt d. All rights reserved.