IMMUNOHISTOCHEMICAL LOCALIZATION OF ESTROGEN-RECEPTOR IN THE NORMAL CANINE FEMALE GENITAL-TRACT

The distribution of estrogen receptor (ER) in the ovaries and uterus w as studied throughout the estrous cycle in the bitch. The stage in the estrous cycle of 25 dogs was assessed by gross and histologic appeara nce of the uterus and ovaries and blood steroid hormone values. Demons tration of ER was performed by an indirect immunohistochemical techniq ue with monoclonal antibodies. ER was found as a red nuclear staining in the surface, crypt, and glandular epithelium; in endometrial stroma cells; and in smooth muscle cells of the tunica muscularis of the ute rus. Total scores of ER-positive cells varied during the estrous cycle , with the highest scores in the early proliferative stage and the low est scores in the early secretory stage of the estrous cycle. These re sults are in concordance with the observations in other animals and th e human uterus. In the canine ovaries, positive staining for ER was pr esent in surface epithelium and subsurface epithelial ingrowths, which is in contrast with negative staining of human ovaries. This study co nfirms the earlier hypothesis that the epithelial ingrowths in canine ovaries may be responsive to blood steroid hormones. (C) Elsevier Scie nce Inc. 1997.