Significance of sex steroids in roles of cadherin subfamily and its related proteins in the uterine endometrium and placenta.

To know the biological functions of the adherens junction in uterine endometrium, mRNA expressions of E-cadherin and alpha- and beta-catenin. which mainly comprise the adherens junction, were determined. Furthermore, to understand various functions related to V-cadherin in the placenta. vessel permeability was determined by assessing V-cadherin mRNA expression in HUV-EC-C cells, derived from the endothelial cells in human umbilical cord. The levels of E-cadherin and alpha- and beta-catenin mRNAs in the endometria of the proliferative phase were significantly less than those of the secretory phase. Treatment with estradiol dipropionate significantly reduced their levels in the endometria of the secretory phase. These suggest that the functions of the adherens junction in endometrial epithelial cell are controlled by sex steroids. On the other hand, estradiol decreased the endothelial cell barrier properties in HUV-EC-C cells, whereas progesterone partly reversed the changes induced by estradiol. While estradiol decreased the level of V-cadherin mRNA in HUV-EC-C cells, progesterone partly reversed the level decreased by estradiol. Therefore, sex steroids play a role in placental development and function related to cadherins on the endothelial cells, probably via placental vessel permeability.