17/3-Estradiol estrogen receptor affinity

The estrogen receptor affinity of EM-652, the active drug of EM-800, was first measured in human breast cancer and normal human uterine cytosol (Asselin et al., 1980). As measured by competition studies in human breast cancer tissue, the affinity of EM-652 (Aj = 0.047 0.003 nM, RBA = 291, relative to 17p -estradiol set at 100), studied in the presence of... 

Comparison of the Estrogen Receptor Affinity of a Series of Antiestrogens and Related Compounds with Estradiol (E2) and Diethylstilbestrol (DES) in... 

In vivo studies in animals suggest that endosulfan may disrupt normal reproductive hormone levels in male animals, but that it is not an endocrine disrupter in females. Persistent depressed testicular testosterone was seen in male rats after intermediate duration oral exposures to endosulfan. In ovariectomized female rats, orally administered endosulfan did not induce normal development of female reproductive tissues, and in female mice and immature female rats, acute parenteral exposure to endosulfan did not affect several endocrine-related end points. In vitro studies have evaluated endosulfan for estrogen receptor (ER) and cytosolic protein binding affinity, ER-mediated reporter gene expression, estrogenic induction of cell proliferation, and alteration of relative abundance of active estradiol metabolites. Overall, in vitro evidence in favor of endosulfan estrogenicity indicates relatively weak potency compared to 17[3-estradiol. Apparently contradictory results were reported in different... 

Fulvestrant is an estrogen receptor competitive antagonist that binds to the estrogen receptor with comparable affinity to that of estradiol. Fulvestrant downregulates the estrogen receptor in human breast cancer cells. It is marketed for treatment of hormone-dependent breast cancer (Figure 8.76). °... 

From the molecular modeling analyses of isoprenoid-substituted phenols that did not showed binding affinity for the estrogen receptor, it was indicated that the binding sites at C-3 and C-17 of 17P-estradiol are rigid, but the lipophilic pocket near C-4-C-7 is flexible. 

Anstead, G.M., Carlson, K.E. and Katzenellenbogen, J.A. (1997) The estradiol pharmacophore ligand structure-estrogen receptor binding affinity relationships and a model for the receptor binding site. Steroids,... 

A notable substitution product of ruthenocene is ethynyl-ruthenocene, which can be bound to estradiol, a form of estrogen studied for breast cancer treatment. With the rigid alkyne spacer, the steroid s affinity to the estrogen receptor was surprisingly unchanged upon addition of the metallocene. The addition of organometallic complexes to biomolecules may allow for the selective tuning of properties of the molecule. ... 

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