HORMONAL CONTROL OF PROLIFERATION IN THE GUINEA-PIG UTERUS

Abstract

SUMMARY In the normal non-pregnant guinea-pig uterus, proliferation of the surface epithelium occurred principally on day 3 after oestrus (vaginal opening). Intense mitotic activity occurred on the following day in the lower regions of the glands. Mitotic activity was pronounced in the endometrial stroma on the succeeding 2 days. In the ovariectomized guinea-pig, oestrogen stimulated cell devision only in the surface and superficial glandular epithelia, but conditioned the endometrium to respond to progesterone so that at least 2 successive days of progesterone treatment after oestrogen priming elicited both intense glandular proliferation and extensive stromal cell division, while progesterone alone induced uterine closure. The proliferative responses of the guinea-pig endometrium thus resembled the responses of the rabbit endometrium rather than the rat or mouse endometrial reaction to hormonal stimulation.