Hormones and Dopamine Regulation
Does castration alter dopaminergic neurotransmission to effect changes in male sex behavior? Answer--yes, testosterone facilitates dopamine release!
Studies by Alderson & Baum (1981); Mitchell & Stewart (1989):
castration decreases the level of dopamine within the nucleus accumbens
administration of testosterone, or estrogen plus dihydrotestosterone, increases dopamine levels within this nucleus
Study by Hull et al. (1997):
castration decreases release of dopamine within the MPOA in response to a precopulatory period (female behind barrier) or interactions with an estrous female
some castrates (1 week) showed dopamine release in MPOA and engaged in sex behavior (short-term response; eventually all castrated males will stop mating)
administration of testosterone proprionate restored release of dopamine within MPOA in response to precopulatory period and facilitated mating