The effects of copulatory behavior on splenic natural killer cell cytotoxicity in male Golden hamsters

Sexual behavior is associated with the release of a number of neuroendocrine hormones and peptides. Several of these have been shown to influence immune function, including cortisol, testosterone, prolactin, and beta-endorphin. The possibility that the release of these immunomodulators coincident with mating has an effect on specific components of the immune response was explored in male Golden hamsters (Mesocricetus auratus) mated either once or weekly for five weeks with sexually receptive females. Maters showed a significant suppression of splenic natural killer cell cytotoxicity (NKCC) two hours after mating compared to matched virgin controls. Natural killer cell activity returned to control levels within 16 hours of mating in both one- and five-time maters. Cytotoxicity was determined using a standard four-hour chromium-51 release assay in all experiments.