ENDOCRINE EFFECTS OF TAMOXIFEN IN POSTMENOPAUSAL BREAST-CANCER PATIENTS

The effects of tamoxifen on plasma concentration of gonadotropins, prolactin (PRL), estrone (E1), estradiol-17.beta. (E2), and sex hormone-binding globulin (SHBG) were studied in 40 postmenopausal breast cancer patients. The changes induced by the drug on endometrium and vaginal epithelium were investigated. After 6-8 wk of tamoxifen treatment, a significant decrease in FSH, lutropin and PRL basal levels was observed, whereas the concentrations of E1 and E2 were not significantly affected. A significant increase in SHBG levels was induced by prolonged treatment with the drug. Tamoxifen caused a partial estrogenization of vaginal smears; and a weak stimulatory effect on endometrium was also apparent. Tamoxifen evidently produced agonistic effects on some targets and antagonistic effects on the others.