Male induced puberty in female mice: evidence for a synergistic action of social cues

Abstract

It has been established previously that cohabitation with an adult male induces precocial puberty in female mice and, furthermore, that a factor in the male's urine is only in part responsible for this phenomenon. The present 4 sets of experiments had as their objective a more precise determination of the male's relevant cues. Exposure of immature females of a particular body wt to intact male urine for 54 hr yielded a small but consistent level of uterine growth. Cohabitation with a castrated male for the same length of time resulted in no uterine growth. Simultaneous exposure to intact male urine and the presence of a castrated male, on the other hand, yielded uterine growth of a magnitude similar to that obtained by cohabitation with an intact male. Further experiments using wire mash barriers, opaquing the eyes and/or occluding the ear canals verified that the second type of cue was tactile and, by extension, that castrated males showed the necessary tactile responses. Thus, the relevant cues of the male are pheromonal and tactile and these cues act synergistically to induce precocial puberty in young females.