부산대학교 도서관

In this study, we compared the uterine tissue of estrogen receptor (ER) [[beta].sup.-/-] mice and their WT littermates for differences in morphology, proliferation [the percentage of labeled cells 2 h after BrdUrd injection and EGF receptor (EGFR) expression], and differentiation (expression of progesterone receptor, E-cadherin, and cytokeratins). In ovariectomized mice, progesterone receptor expression in the uterine epithelium was similar in WT and ER [[beta].sup.-/-] mice, but E-cadherin and cytokeratin 18 expression was lower in ER[[beta].sup.-/-] mice. The percentage of cells in S phase was 1.5% in WT mice and 8% in ER[[beta].sup.-/-] mice. Sixteen hours after injection of 17[beta]-estradiol ([E.sub.2]), the number of BrdUrd-labeled cells increased 20-fold in WT mice and 80-fold in ER[[beta].sup.-/-] mice. Although ER[alpha] was abundant in intact mice, after ovariectomy, ER[alpha] could not be detected in the luminal epithelium of either WT or ER[[beta].sup.-/-] mice. In both untreated and [E.sub.2]-treated mice, ER[alpha] and ER[beta] were colocalized in the nuclei of many stromal and glandular epithelial cells. However, upon [E.sub.2] + progesterone treatment, ER[alpha] and ER[beta] were not coexpressed in any cells. In WT mice, EGFR was located on the membranes and in the cytoplasm of luminal epithelium, but not in the stroma. In ER[[beta].sup.-/-] mice, there was a marked expression of EGFR in the nuclei of epithelial and stromal cells. Upon [E.sub.2] treatment, EGFR on cell membranes was down-regulated in WT but not in ER[[beta].sup.-/-] mice. These findings reveal an important role for ER[beta] in response to [E.sub.2] and in the organization, growth, and differentiation of the uterine epithelium. differentiation | proliferation | uterus