Male acceleration of puberty in female mice (Mus musculus)

Nine experiments were performed to investigate various aspects of the acceleration of puberty in female house mice produced by the presence of a male mouse or urine from males. The findings include the following: (a) Grouping males has no effect on the urinary chemosignal that accelerates puberty except that (b) urine from dominant males produces greater acceleration than urine from subordinates. (c) Young female mice must be exposed to the male urine for at least 2-3 hr/day or to the presence of a male for 1 hr/day to produce acceleration of first vaginal estrus. (d) Females are accelerated to the same extent in attaining puberty whether treated with urine from the same male or a different male each day. (e) Urine from the father or a full brother, or the presence of those close relatives, exerts no differential acceleratory or retarding effect on puberty when compared with urine from or the presence of unrelated males. (f) Excreted or bladder urine from adrenalectomized males accelerates puberty to the same extent as urine from intact males, but (g) the presence of an adrenalectomized male does not produce the same degree of acceleration that occurs when an intact male is present. (h) Behavioral observations indicate that adrenalectomized males pursue young females less and attempt fewer mounts during a brief test period. Together, these findings have some important consequences with respect to our understanding of both the mechanisms of acceleration of puberty in the house mouse and the population and reproductive biology of these mice.