Abstract
Histochemical identification and visualization of steroid hormone receptors remains a goal, despite earlier success with dry- and thaw-mount autoradiography. Applications of various histochemical and immunohistochemical procedures for the identification of steroid hormone target cells and subcellular binding sites are reviewed. Results obtained with dry- and thawmount autoradiography after in vivo administration of [3H] estradiol are contrasted with those obtained by in vitro liquid emulsion autoradiography, incubation with conjugated estradiol, antibodies to estradiol, or antibodies to estradiol “receptor”. Dry- and thaw-mount autoradiography in vivo after single injection of [3H] estradiol, and in vitro after tissue slice incubation with [3H] estradiol consistently show preferential nuclear concentration of radioactivity, little in cytoplasm, and none in nucleoli. In contrast, liquid emulsion autoradiography after in vitro uterine section incubation with [3H] estradiol shows no nuclear uptake, but only labeling of cytoplasm of eosinophils. Eosinophils are also labeled with conjugated estradiol. Histochemical studies with conjugated estradiol or estradiol antibodies show variable results with preferential cytoplasmic and distinct nucleolar labeling of uterine epithelial and stromal cells; however, there is only occasional nuclear labeling, and some lack of identification of target cells, when compared to results obtained with our autoradiographic techniques. The specificity and utility of certain histochemical techniques need to be established, since some of the results are probably related to technique and do not reflect biological events. Development and use of refined histochemical techniques are needed to further contribute to the clarification of the mechanism of steroid hormone action and to provide a tool for the clinical diagnosis of steroid hormone dependent tumors.
