Daily administration of estrogen antagonists to premenopausal women has been incorporated into the adjuvant treatment of breast cancer. We have studied the changes in reproductive hormones, pituitary responses to hypothalamic-releasing hormones, and endometrial histology during treatment with the antiestrogen tamoxifen in five healthy, premenopausal women. These studies were carried out during one menstrual cycle before and during two cycles of antiestrogen treatment. All subjects continued to have regular menses with biphasic basal body temperature records. During treatment, estradiol (E2) levels were increased but followed the usual pattern reflecting follicular maturation and corpus luteum formation. The mean E2 concentration at the midcycle peak and during the luteal phase was twice that observed during the non-treatment cycle. By contrast, the concentrations and secretory patterns of luteinizing hormone and follicle-stimulating hormone were not greatly changed, and the gonadotropin responses to gonadotropin-releasing hormone were not suppressed.
Barry M. Sherman, Frederick K. Chapler, Kent Crickard, Dorothy Wycoff