Postmenopausal hormone replacement therapy with estrogen periodically supplemented with antiestrogen.

To inhibit endometrial stimulation during postmenopausal estrogen therapy, 25 women with climacteric symptoms were treated with a daily dose of 1.25 mg of conjugated estrogens for 7 weeks followed by a period of 10 days with clomiphene citrate administration (50 mg per day). This combination was repeated three times during the 6-month trial. The marked relief of climacteric symptoms with estrogen was slightly less during clomiphene treatment. Uterine bleeding occurred five times during estrogen treatment periods but never during or after clomiphene supplementation. Histologic examination revealed endometrial atrophy in 41% of the samples after the first estrogen treatment, whereas after the first and third clomiphene periods this was increased to 77% and 73%, respectively. The first clomiphene treatment significantly decreased the concentrations of cytosol estrogen and progestin receptors in endometrium, as compared with the levels recorded at the end of the preceding estrogen therapy. The depression in the cytosol estrogen receptor concentration was persistent, whereas cytosol progestin receptor concentration tended to increase during the subsequent estrogen-plus-clomiphene treatment. Estrogen declined serum concentration of follicle-stimulating hormone (FSH), whereas the concentration of luteinizing hormone (LH) and prolactin remained unchanged. Clomiphene did not change the levels of these hormones from those observed during the estrogen treatment. The concentration of free fatty acids in serum was increased during the estrogen and clomiphene treatments, whereas the levels of cholesterol and high-density lipoprotein--cholesterol did not change. Our results suggest that this treatment regimen relieves climacteric symptoms without endometrial stimulation or other adverse effects. Thus, clomiphene appears to be a practical alternative to progestin for interruption of the postmenopausal endometrial effect of estrogen.