[A progesterone-dependent pheromone of the female mouse (author's transl)]

Female mice kept in groups exhibit less oestrous smears than females kept singly. Ovariectomized females have only slightly reduced number of oestrous smears, but ovariectomized females injected with progesterone act on other females like intact ones. It is concluded that a progesterone-dependent pheromone excreted by dioestrous females acts oestrus-depressing on other females.