Acceleration of puberty in female mice by a urinary chemosignal from pregnant or lactating females: timing and duration of stimulation.

Six experiments were designed to test the acceleration of puberty in young female mice treated with urine from pregnant or lactating females. Manipulations involved varying the age of onset for and duration of treatment with urine. For both urine sources the findings were similar: 1 day of treatment was insufficient to accelerate puberty, but a minimum of about 3 consecutive days of urine exposure begun before the mice were 30 days of age did hasten the onset of first vaginal estrus.