2-Hydroxyestradiol-17α and 4-hydroxyestradiol-17α, catechol estrogfn analogs with reduced estrogen receptor affinity

2-Hydroxyestradiol-17α and 4-hydroxyestradiol-17α, the catechol derivatives of estradiol-17α, have reduced affinity for hypothalamic, pituitary, and uterine estrogen receptors, but retain a potency for interaction with catechol-O-methyltransferase equal to that of the natural, 17β-hydroxy catechols. This dissociation of receptor binding and catecholamine interactions nay allow the use of the 17α catechols as a probe for the mechanism of action of the catechol estrogens.