Contact stimulation, androgenized females and accelerated sexual maturation in female mice

Abstract

Adult female mice previously given 100 μg of testosterone propionate on day 1 of age were placed with 21-day-old female mice producing an acceleration of vaginal introitus and first vaginal estrus in the young females. Young test females placed with intact adult males attained first estrus at 27.9 days of age while test females placed with neonatally androgenized females matured at 30.5 days of age and single control females matured at 34.0 days of age. Androgenized females caused an acceleration of maturation in young females, but not by the production of an acceleratory pheromone as in adult intact males. A second experiment demonstrated that contact stimulation with the young females by neonatally androgenized adult females was equal in quantity and similar in quality to the contact by normal adult males. In a final experiment young females were exposed to the continued presence of a neonatally androgenized adult female and a daily sample of male-soiled bedding containing the maturation-accelerating pheromone; these females matured at 28.1 days of age, the same age as young females placed with intact adult males. Contact stimulation may explain the acceleration of sexual development produced by placing young female mice with neonatally androgenized adult females. Such contact could explain a portion of the male-acceleration effect; that portion not accounted for by pheromonal factors.