The abuse of anabolic-androgenic steroids noted in recent years has be
en correlated with an increased likelihood of abuse of other drugs, in
cluding cocaine. This research was designed to investigate whether man
ipulation of androgen levels would alter the unconditioned behavioral
effects of cocaine. The influence of testosterone on the locomotor act
ivating effect of oral cocaine was evaluated. Subjects were male gonad
ally intact and castrated Wistar rats, implanted s.c. with either plac
ebo or 100 mg testosterone 30-day pellets. Beginning 7 days after pell
et implantation, each animal in the four subgroups randomly received 0
, 20, 40 and 80 mg/kg cocaine (once, each dose). Cocaine 80 mg/kg sign
ificantly enhanced locomotor activity in all groups except the intact
testosterone-treated group. Of the four groups, this subgroup would ha
ve the highest plasma level of testosterone. These data suggest that c
hronic exogenous androgen administration may reduce the behavioral eff
ects of cocaine.