The baboon as a primate model for the study of endometrium.

A series of transcervical uterine biopsy specimens were obtained at various stages of the menstrual cycle from a colony of 11 normally cycling female baboons, Papio anubis and Papio cynocephalus. Morphologically, baboon endometrium appeared to be similar to human endometrium. Alkaline phosphatase activity was maximal throughout the preovulatory phase and during the late postovulatory period. During the preovulatory phase acid phosphatase was not demonstrable but increased after ovulation to reach maximal activity prior to menstruation. While differences exist between human and baboon endometria, the overall morphologic and histochemical changes are similar. In addition, the baboon's endometrium is readily accessible by transcervical uterine biopsy, thus making these animals valuable primate models for study of human reproductive problems.