THE CYCLICAL CHANGES IN THE MUCOSA OF THE GUINEA PIG’S UTERUS, CERVIX AND VAGINA AND IN THE SEXUAL SKIN, INVESTIGATED BY THE ELECTRON MICROSCOPE11

Abstract

The mucosa of the guinea pig''s endometrium, cervix and vagina and the epithelium of the perivaginal (sexual) skin have been studied with the electron microscope during estrus, metestrus and late diestrus. During estrus, the uterine epithelial cells, the superficial mucous cells of the cervical epithelium as well as the basal and prickle cells of the vaginal epithelium display microvilli on their surfaces; these disappear during diestrus. Throughout the cycle in the cervix and during diestrus in the vagina, the superficial epithelial cells are filled with large droplets of a low-density material, apparently mucus. This seems to arise within distended vesicles of the endoplasmic reticulum in lower cells. During estrus in the vagina and at all times in the sexual skin, the uppermost epithelial cells consist mainly of filaments. In the basal cells, these filaments occur in small clusters anchored on thickenings on the cell surfaces. Such cells contain an abundance of dense cytoplasmic particulates presumed to be ribonucleoprotein; an endoplasmic reticulum is absent or poorly developed. The transitional layer of the vaginal epithelium during estrus shows a gradual retraction and apparent dissolution of the nuclei, paralleled by a swelling, vacuolization and disappearance of the mitochondria. Some correlations have been drawn between the present observations and those reported earlier (Endocrinology 59 93. 1956) for the histochemical characteristics of these same tissues.