β-Glucuronidase activation of latent aggression-promoting cues in mouse bladder urine

The present study was designed to investigate the chemical properties of the aggression-promoting cues present in bladder urine of male mice. The results of the first experiment confirmed earlier work by demonstrating the presence of an aggression-promoting chemosignal in bladder urine. In Experiment 2, behavioral assays were separately performed on the organic and aqueous layers of bladder urine obtained by repeated dichloromethane extractions. Only the combined organic layers of the initial three extractions demonstrated behavioral activity. A fourth extraction showed no behavioral activity for both organic and aqueous layers. However, the findings of Experiment 3 showed that incubation of the aqueous layer from the third CH₂Cl₂ extraction in β-glucuronidase can free additional aggression-promoting cues into a subsequent CH₂Cl₂ extraction. It is concluded that two forms of the aggression-promoting chemosignal are present in bladder urine. One is lipophilic and behaviorally active, whereas the other is conjugated, possessing latent chemosignal properties.