Steroid hormones receptor assay

Gaido, K.W., Leonard, L.S., Lovell, S., Gould, J.C., Babai, D., Portier, C.J., and McDonnell, D.P., Evaluation of chemicals with endocrine modulating activity in a yeast-based steroid hormone receptor gene transcription assay, Toxicol. Appl. Pharmacol., 143, 205-212, 1997. 

Steroid hormones achieve their effects on target tissues through intracellular receptor proteins. According to recent views, oestrogen and progestin receptors are localized in the nuclear compartment of the cells, whereas glucocorticoid receptors may reside in both the cytoplasm and the nucleus. Determination of the intracellular localization of androgen receptors awaits the development of (monoclonal) antibodies which will enable immunohistochemical studies. The molecular aspects of the mechanism of action of steroid hormones will be covered in other chapters [1-3] in this volume. The present chapter deals with the characterization, assay and purification of steroid receptors. 

In addition to the actions mediated by intracellular receptors, steroid hormones also demonstrate certain rapid (occurring within seconds) actions, which appear to be mediated by membrane effects/receptors this is true for vertebrate [114] and invertebrate [115] steroids. One presumes that the SAR studies for ecdysteroids which have been performed to date are predominantly determined by interaction of ecdysteroids with nuclear receptors, but one should bear in mind that in certain assay systems the... 

DSL Diagnostic Systems Inc. (2005) Steroid hormone assays for clinical diagnostics and research applications. http //secure.dslabs.com/Products/ProdInfo.asp Lieberman BA (ed) (2001) Steroid receptor methods protocols and assays. Methods in molecular biology, vol 176. Humana Press, Totowa, NJ... 

Wilkinson, J.M. et al. 2008. Compound profiling using a panel of steroid hormone receptor cell-based assays. J. Biomol. Screen. 13, 755-765. 

Figure 2 General steps in steroid hormone action and their assays. The basic model depicts steroid (S) binding to its receptor molecule (R) to form receptor-steroid complexes (RS), which attach to biologically active DNA binding sites (HRE) to eventually produce changes in the levels of specific proteins. Experimental techniques to follow R at various stages in this pathway are indicated at the first point that each method can detect a signal. Most methods can also be used to detect receptors at any step downstream of the one for which it is first used.

The majority of studies correlating CD with tumor progression and prognosis have used an immunoradiometric assay that detects both the proforms and mature forms of CD. This assay can be used to measure CD in tissue extract generated for detection of steroid hormone receptors. CD has also been measured by western blot, by immunohistochemistry, and by activity. 

Titration assays, enzyme immunoassays, and immuno-cytochemical assays are used to measure steroid hormone receptors. 

Smith, R. G., Quality control in steroid hormone receptor assays. Cancer (Philadelphia) 46, 2946-2949 (1980). 

The aim of this assay is to evaluate the expression of steroid receptors (receptor status) in hormone-dependent tumors, since these receptors (estrogen, progesterone and androgen receptors) are essential for the proliferation and differentiation of tumors derived from hormone-dependent tissues such as breast, ovarian and uterine tissue. 

Organometallic derivatives of steroid hormones have been used to study ligand-receptor interactions for quite some time, SERMs with anti-tumor activity have already been discussed in Section 1.31.3.1. Other applications were developed for metallo-immuno assays and are discussed in Section 1.31.5.3. For such applications, binding of the organometallic compound to a receptor is necessarily implied but not always proved or quantified. 

The G. interact with specific receptors in the theca and foUicle cells of the ovary and corpus luteum and with the interstitial cells of Leydig in the testes. cAMP is released as a second messenger to stimulate the production of steroid sex hormones. G. can be determined by radioimmunoassay, the radioligand-hormone receptor method, or by biological assays (see Hormones). 

Most steroid-sensitive cancers express specific cell surface receptors. Prednisone-sensitive lymphomas, estrogen-sensitive breast cancers, and prostatic cancers express specific receptors for corticosteroids, estrogens, and androgens, respectively. It is now possible to assay tumor specimens for steroid receptor content and to identify which individual patients are likely to benefit from hormonal therapy. Measurement of the estrogen receptor (ER) and progesterone receptor (PR) proteins in breast cancer tissue is now standard clinical practice. ER or PR positivity predicts response to hormonal therapy, whereas patients whose tumors are ER-negative generally fail to respond to such treatment. 

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