Immunohistochemical detection of estrogen receptor alpha in the growing and regressing ovaries of newly hatched chicks.

The aim of this study was to detect the presence of estrogen receptor alpha in different cell subpopulations of the growing left and regressing right ovaries from newly hatched chicks, by immunohistochemical methods, using an indirect immunoperoxidase technique. Newly hatched chicks were killed by decapitation and the growing left and regressing right ovaries were removed and processed for histological and immunohistochemical studies. The percentage of estrogen receptor alpha (ERalpha) immunostained cells and the staining intensity were determined. Histological results demonstrated that the right ovary lacks cortex and is constituted by the medullary region, whereas the left ovary is composed by cortical and medullary compartments. The medullary region is similar in both ovaries and presents the same elements. Immunohistochemical analysis revealed ERalpha-positive cells in the left ovary, located in the nucleus of all cell subpopulations; in contrast, in the right ovary, only epithelial cells of the lacunar channels depicted estrogen receptors. The present findings indicate a cell-specific localization of ERalpha in left and right ovaries of newly hatched chick.