Alterations in cell proliferation and morphology of ampullar epithelium of the mouse oviduct during the estrous cycle

Abstract

We examined cell proliferation and morphological changes in the ampullar epithelium of mouse oviducts. Oviducts were labeled in vivo by administration of 5-bromo-2′-deoxyuridine (BrdU) on each day of the estrous cycle. The frequency of the ampullar S-phase epithelial cells labeled with BrdU changed according to the estrous cycle, with the highest proportion at proestrus. The morphology of the ampullar epithelia also changed during the estrous cycle. In estrus and metestrus, most of the ampullar epithelial cells were comprised of non-ciliated secretory cells. In diestrus and proestrus, however, the ciliated cells were dominant among the ampullar epithelial cells. Electron microscopic observations indicated that the ampullar non-ciliated secretory cells in metestrus had numerous secretory granules, and fusion of these granules with the plasma membrane, i.e. exocytosis, was evident. The present results indicate that cell proliferation and morphology of ampullar epithelia of mouse oviducts vary according to phase of the estrous cycle.