The Role of the Vomeronasal Organ in Shortened Estrous Cycle of Female Mice in the Presence of Males

Abstract

It is known that a four-day estrous cycle is frequently shortened to 3 days in IV CS female mice in the presence of males. This phenomenon is generally attributed to functions of the female's olfactory system. This olfactory system consists of two systems: 1) the olfactory epithelium-main olfactory bulb (main olfactory) system and 2) the vomeronasal organ-accessory olfactory bulb (accessory olfactory) system. In this study we examined the effects of the removal of the vomeronasal organ on the shortening of the estrous cycle. Eight of 18 sham operated females underwent a 3-day estrous cycle (44.4%), while all of 15 females with their vomeronasal organs excised underwent a regular 4-day estrous cycle. These results suggest that the accessory olfactory system plays an important role in the shortening of the estrous cycle.