Progesterone: Effects on investigatory preferences, aggression, and olfaction in orchidectomized, testosterone-treated mice

Effects of testosterone alone and in combination with progesterone on investigatory preferences, fighting, and olfaction in castrated male CD-1 mice were assessed. Testosterone stimulated both preferences for intact male mice and aggression, while progesterone reduced attention to intact male mice and reduced aggression. Accessory sex tissue weights and olfactory ability were unaffected by progesterone treatment. The possibility of a centrally located antagonism of testosterone by progesterone exclusive of the olfactory system is discussed.