Male-induced implantation failure (the Bruce effect) in mice: Protective effect of familiar males on implantation

Abstract

Housing newly inseminated female mice in contact with a familiar male (a male that had cohabited with the female for 24 h during the pericopulatory period, but not the coital partner) depressed the implantation failure (the Bruce effect) induced by exposure to alien males. This is comparable to the protective effect of stud males on implantation in alien male-exposed females. The findings imply that exposure to a male (stud or any other) during the pericopulatory period enables the female to memorize the male-originating olfactory cues, and that this memory formation is not contingent upon mating. Reexposure to the male-originating olfactory cues induces a luteotrophic effect in the newly inseminated female, which accounts for the protective effect of the stud/familiar male on implantation in the alien male-exposed female. The male-originating olfactory cues that provide the protective effect on implantation act through contact. The findings also lend support to the view that the female mouse is capable of identifying a male as an individual through olfactory cues perceived during the pericopulatory period.