María Teresa Arnedo

Rewarding Properties of Testosterone in Intact Male Mice: A Pilot Study

The present study examined the rewarding properties of 4-androsten-17beta-ol-3-one testosterone in intact male mice using the conditioned place preference (CPP) technique. In Experiment 1, the pharmacokinetics of 0.8 and 1.2 mg/kg of testosterone were studied to determine the most appropriate temporal interval to test behavior. Additionally, the locomotor activity was recorded to control a possible interfering effect on CPP. The maximum testosterone concentration was registered at 45 min of administration, and no effects on activity were found. In Experiment 2, three groups of male OF-1 mice received four pairings of the least-preferred compartment with testosterone (0.8, 1, or 1.2 mg/kg, SC) for 30 min. On alternate days the preferred compartment was paired with vehicle for 30 min. The control group received vehicle in both compartments. No significant differences between groups were found in the time spent in the drug-paired compartment. However, when separate analyses were performed in conjunction with the color of the drug-paired compartment. CPP was observed only in animals pairing testosterone/black compartment. These results suggest that rewarding properties of testosterone treatment can be observed in male mice; these effects probably being dependent on the environmental cues used as conditioned stimuli.

Testosterone and attribution of successful competition

Mood, personal merit, and/or its perception have been suggested to be mediating factors in testosterone responses to competition. Previously we have found that personal contribution and attribution were related to testosterone levels after successful competition. To confirm such associations, two basketball teams (n = 17 players) that emerged as winners in two actual matches were studied. Salivary testosterone levels and mood were measured before and after the games. Individual contribution to the outcome was assessed, and personal satisfaction and causal attribution of outcome were reported by players. Testosterone concentrations increased to near significance in Team 1 but not in Team 2, who attributed their victory more to luck than did Team 1. This latter team showed notably decreased vigor, and both teams showed fatigue at the end of the match. Post-match testosterone levels were only significantly, negatively related to external attribution. The results support the idea that causal attribution of the outcome is contributing to the variance of the testosterone responses to real confrontations where the outcome is highly dependent on personal merit.