Lack of copulatory behaviour in male castrated rats after p-chlorophenylalanine

1 The effect of p-chlorophenylalanine (PCPA) on the copulatory behaviour of normal and castrated male rats with females in oestrus was studied.2 Castration 2 months before the experiment completely prevented the increased copulatory behaviour produced by PCPA in normal rats.3 The administration of testosterone restored the copulatory behaviour in the castrated rats indicating that testosterone is essential for this behaviour.