Binding With the Estradiol Template

Building off of the previous SAR work by Blair et al. [21] and Branham et al. [11], Fang et al. [22] concluded that five distinguishing criteria were essential for xenoestrogen activity, using E2 as a template  

1) H-bonding ability of the phenolic ring, as occurs with 3-OH 

3) precise steric hydrophobic centers analogous to steric 7a- and 11 (3-substituents 

They also reported that on the basis of a review of data on over 2000 chemicals that have been tested in various in vitro and/or in vivo assays, all chemicals showing estrogenic properties contained a ring structure. All except five of the ring structures were aromatic (the exceptions being four steroids and the pesticide kepone). Table 18.1 illustrates the presence of these features in various categories of chemicals. 

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