Histochemical localization of estrogen and progesterone receptors: Evaluation of a method

Abstract

A histochemical method for the detection of estrogen (ER) and progesterone (PR receptors in human endometrium, using estrogen and progesterone derivatives linked to fluorochrome-labeled bovine serum albumin (E2-BSA-fluorescein isothiocyanate (FITC) and progesterone-BSA-tetramethylrhodamine isothiocyanate (TMRITC), has been evaluated. The fluorochrome-labeled steroids were bound to the cytoplasm - preferably in glandular epithelial cells but too a lesser extent also to stromal cells. The steroid specificity of the observed binding was studied by preincubating the sections with a series of unlabeled steroids and nonsteroidal, hormonally active compounds (estradiol-17β, diethylstilbestrol, tamoxifen, 5α-dihydrotestosterone and R 1881 for ER and ORG 2058, R5020, dexamethasone, cortisol and 5α-dihydrotestosterone for PR). The inhibition studies indicated the E2-BSA-FITC and progesterone-BSA-TMRITC bind to ER and PR in human endometrium with a reasonable degree of specificity. The method was reproducible and various procedural steps were tested, showing satisfactory technical stability. The method is applicable to small tissue samples, and is a valuable complement to quantitative biochemical receptor assays, as it localizes the receptors in tissue slices.