Copulatory plug does not induce luteal activity in the mouse Mus musculus.

In the normal oestrous cycle of the female house mouse, a true luteal phase is absent. Some unknown stimulus provided by the male during mating induces the luteal phase of the oestrous cycle in the female. Land & McGill (1967) initiated a search for this stimulus. They recognized three possible sources of stimulation from the male that might be either sufficient or necessary for the induction of luteal activity. These were: (a) a minimum number of preejaculatory thrusts, (b) the ejaculatory reflex and the formation of the copula¬ tory plug, and (c) the subsequent presence of the plug in the vagina. Their results indicated that up to 150 pre-ejaculatory thrusts were neither sufficient