EXPRESSION OF KERATINS IN MOUSE VAGINAL EPITHELIUM

In the epithelium of the rodent vagina proliferation and differentiati on are tightly regulated by ovarian hormones. Estrogens stimulate prol iferation and squamous differentiation, whereas progesterone redirects differentiation to a mucus-secreting epithelium formed by goblet-like cells. In the present study, we used monospecific keratin antibodies to show the expression and distribution of keratins in SENCAR mouse va ginal epithelium in different stages of the estral cycle and in ovarie ctomized animals. In ovariectomized animals, the vaginal epithelium ex pressed K6, K8, K13 and K14, but not K1. After estrogen treatment, K1 was expressed. During proestrus and estrus, the keratin pattern was es sentially identical to that observed in 17 beta-estradiol-stimulated a nimals. In contrast, during the progestational stages (metaestrus and diestrus) or after progesterone treatment of ovariectomized mice, the most relevant change was the loss of K1. Together, these results show that K1 expression is induced by estrogens in the vaginal epithelium. In contrast, K6, K8, K13 and K14 are constitutively expressed even whe n squamous differentiation is not observed.