[The anti-estrogenic effect of 4-chloro-1,2-diphenyl-1-(4-[2-(N,N-dimethylamino)ethoxy]phenyl)1-butene (Toremifene) on the endocrine regulation in breast cancer patients].

In a combined phase I-II study the hormonal effects of Toremifene were investigated in 15-15 patients at two dose levels: 60 mg and 300 mg per os, daily. Serum estradiol, progesterone, testosterone, follicle-stimulating hormone, luteinizing hormone, prolactin, human growth hormone were monitored by radioimmunoassay and sexual hormone binding globulin by immunoradiometric assay prior to treatment and at the 2nd, 8th and 12th weeks. The influence of Toremifene upon the hypothalamo-hypophyseal axis was also controlled by a tirotropin releasing hormone functional test using 400 micrograms tirotropin releasing hormone injection iv. Estradiol, progesterone, follicle-stimulating hormone, luteinizing hormone and prolactin decreased proving the antiestrogenic activity of the drug. Sexual hormone binding globulin significantly (p less than 0.002) increased by week 12 at both doses, probably due to a direct effect of Toremifene upon the liver. The increase in sexual hormone binding globulin suggests the partial estrogenic effect of the drug. The tirotropin releasing hormone induced prolactin release was also suppressed. On the basis of hormonal changes and the clinical response of patients 60 mg of Toremifene proved to be as effective as 300 mg.