Ultrastructural Changes of Stromal Cells in the Hamster Uterus During Pseudopregnancy

It is well known that the uterus is involved in regulating the lifespan of the corpus luteum in several species of farm and laboratory animals. Removal of the uterus during the luteal-phase of the estrous cycle or during particular days of pseudopregnancy extends corpus luteum lifespan to approximately that of gestation. These studies suggest that the uterus is in some way responsible for the normal regression of the corpus luteum. The purpose of the present study was to determine if ultrastructural changes could be detected in the endometrial stromal cells of the hamster uterus during that phase of pseudopregnancy in which the uterus influences the corpus luteum lifespan.