-
Views
-
Cite
Cite
Madhabananda Sar, Frank Welsch, Differential Expression of Estrogen Receptor-β and Estrogen Receptor-α in the Rat Ovary, Endocrinology, Volume 140, Issue 2, 1 February 1999, Pages 963–971, https://doi.org/10.1210/endo.140.2.6533
- Share Icon Share
Abstract
Immunohistochemical localization of two estrogen receptor (ER) subtypes, ERβ and ERα, was performed in neonatal, early postnatal, immature, and adult rats to determine whether ERα and ERβ are differentially expressed in the ovary. ERβ and ERα were visualized using a polyclonal anti-ERβ antibody and a monoclonal ERα (ID5) antibody, respectively. Postfixed frozen sections and antigen-retrieved paraffin sections of the ovary revealed nuclear ERβ immunoreactivity (IR) in granulosa cells, which was prevented when peptide-adsorbed antibody was used instead. In immature and adult rat ovaries, ERβ was expressed exclusively in nuclei of granulosa cells of primary, secondary, and mature follicles. Atretic follicle granulosa cells showed only weak or no staining. No specific nuclear ERβ IR was detected in thecal cells, luteal cells, interstitial cells, germinal epithelium, or oocytes. In neonatal rat ovary, no ERβ expression was found. In ovaries of 5- and 10-day-old rats, weak ERβ IR was observed in granulosa cells of primary and secondary follicles, but no staining was detected in the primordial follicles. ERα protein exhibited a differential distribution in the ovary with no detectable expression in the granulosa cells but evidence of ERα IR in germinal epithelium, interstitial cells, and thecal cells. In the oviduct and uterus, IR for ERα, but not ERβ, was found in luminal epithelium, stromal cells, muscle cells, and gland cells. Our present study demonstrates that ERβ and ERα proteins are expressed in distinctly different cell types in the ovary. The exclusive presence of ERβ in granulosa cells implies that this specific new subtype of ERβ mediates some effects of estrogen action in the regulation of growth and maturation of ovarian follicles.