[Development of new antiestrogens of the 3,3'-dihydroxy-alpha, beta-diethylstilbene-type and their evaluation on the DMBA-induced hormone dependent mammary carcinoma of the SD-rat (author's transl)].

The displacement of the phenolic OH-group of diethylstilbestrol into the 3,3'-position (trans-3,3'-dihydroxy-alpha, beta-diethylstilbene, compd. III) leads to a strong decrease of the estrogenic effect under conservation of the receptor affinity. In vitro, III inhibits the estradiol-receptor-interaction competitively and, in vivo, antagonises the uterotropic effect of estrone in the mouse. In tests with the DMBA-induces, hormone-dependent mammary carcinoma of the rat a dose-dependent strong decrease of tumor size and yield is achieved under the influence of III, due to the antiestrogenic properties of III. The replacement of the alpha, beta-bound ethyl groups in III by other alkyl chains leads to no further increase of the antiestrogenic and antitumor activity.