THE RELATIONSHIP BETWEEN AGGRESSIVE AND SEXUAL-BEHAVIOR IN MALE-MICE - EFFECTS OF TESTOSTERONE AND PARACHLOROPHENYLALANINE

The purpose of this study was to clarify the connection between aggres sive and sexual behavior with the aid of testosterone propionate (TP) and parachlorophenylalanine (PCPA). Previous studies have indicated th at aggressive and sexual behavior are positively correlated, and it ha s been suggested that both behaviors are related to the level of gener al arousal. Testosterone has documented effects on both aggressive and sexual behavior. It has been hypothesized that these effects are due to an increased level of general arousal. If this is the case, aggress ive and sexual behavior could be restored by administration of drugs e xcitating the central nervous system, e.g., PCPA. The present study ex amined the effects of TP and PCPA on aggressive and sexual behavior in gonadectomized male mice. Control animals were injected with sesame s eed oil or saline. The level of aggressiveness was assessed by means o f dyadic tests with gonad-intact male opponents. For the sexuality tes ts, a receptive female was placed in the home cage of the experimental male. The results showed that male mice injected with PCPA were more aggressive than the males of the other groups, while the TP-exposed ma les expressed the most sexual activity. Compared to the control group, the PCPA and TP groups were more active in both the aggression and th e sexuality tests. These findings lend support to the hypothesis that the earlier documented correlations between aggressive and sexual beha vior could be due to both behaviors being dependent on a certain level of general activation. (C) 1998 Wiley-Liss, Inc.