ABSTRACT
Peroxidase-labeled estradiol-bovine serum albumin (BSA) conjugates can be used to assess steroid binding in breast carcinomas, although with the range of concentrations used it is likely that it is type II binding sites that are detected. The approaches available for the histological demonstration of steroid binding utilizing peroxidase are similar to those for fluorescein, namely, immunohistochemistry and histochemistry using enzyme-labeled hormone. The immunofluorescent studies have used either monomeric estradiol or polyestradiol phosphate; similar approaches have been used for immunoperoxidase by some workers, but variations have been utilized particularly in studies on animal tissues. The most widely used methods for the conjugation of horseradish peroxidase are the two-stage glutaraldehyde technique of Avrameas and Temynck and the periodate method of Nakane and Kawaoi. The treatment of control sections with tamoxifen or diethylstilbestrol, either prior to the application of estradiol-BSA-peroxidase or as a coincubation, has resulted in a lack of staining, indicating that the binding of the conjugate is to specific sites.
