The competitive binding affinities of thirteen 7-substituted-2,3,-dichlorodibenzo-p-dioxins to the human Ah placental cytosolic Ah receptor were determined versus [3H]-2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) as the radioligand. Multiple parameter linear regression analysis of the competitive binding EC50 values for these compounds gave the following equation: pEC50 (M)=6.246+1.632 π - 1.764σm° + 1.282 HB. were π is the substituent lipophilicity, σm° the meta-directing electronegativity and HB the hydrogen binding capacity. The equation obtained using human placental receptor was different than correlations previously derived for the binding of the same series of compounds to the rat, mouse, guinea pig or hamster cytosolic Ah receptor, providing further evidence for interspecies differences in the properties of the Ah receptor protein.
ASJC Scopus subject areas
- Environmental Engineering
- Environmental Chemistry
- Health, Toxicology and Mutagenesis