Castration decreases olfactory bulb norepinephrine in male rats but not hamsters

Norepinephrine (NE) concentrations were measured in the olfactory bulbs and olfactory cortex of male albino rats and golden hamsters sacrificed 13-16 days after castration or sham surgery. Castration significantly decreased NE concentrations in the olfactory bulbs of rats but not hamsters. Castration had no significant influence on NE levels in the olfactory cortex of either species. Regional brain weights were not influenced by surgery, and previous olfactory exposure had no significant effect on any variable measured. The decrease in rat olfactory bulb NE levels may be involved in castration-induced changes in preferences for conspecific odors.