Abstract
Antiestrogens and partial estrogens of the stilbene (1 and 4), triphenylbutene (2) and diphenylethane (3) series were tested for their potential prostatic tumor inhibiting activity. Compounds 1 and 2 exerted a strong inhibitory activity on prostate and seminal vesicle weight of intact rats and mice, whereas the strong antiestrogen 3 and compound 4 had no or only a slight effect. The tumor inhibiting activity of 1 and 2 on the hormone-dependent R 3327 Dunning prostatic carcinoma of the rat was strong and comparable to that of castration or administration of the potent estrogen DES. Compounds 1-4 had no direct antiandrogenic effect in castrated, testosterone-substituted rats and mice, and no affinity for the androgen or progesterone receptor. To the estrogen receptor from prostatic tumor cytosol, however, 1-4 had good receptor affinities. As the partial antiestrogen 1 and the partial estrogen 2 have much lower estrogenic properties than DES, but still have strong prostatic tumor inhibiting properties, they may offer a suitable alternative to conventional therapy of prostate carcinoma because of their possibly low estrogenic side effects.