Plasma levels of estrogen, luteinizing hormone, and follicle stimulating hormone following castration and estradiol implant.

Plasma levels of luteinizing hormone, follicle stimulating hormone, and estrogen were studied serially in 20 patients before and after hysterectomy and bilateral salpingo-oophorectomy. Ten patients received an implant of estradiol-17 beta (100 mg) at the time of operation. Ten patients who did not receive an implant acted as controls. Patients recorded the severity of vasomotor symptoms before and after hysterectomy. In those patients who did not receive an implant, plasma estrogen levels fell from a mean preoperative level of 18.1 +/- 10.4 ng/100 ml to 8.7 +/- 1.4 ng/100 ml by 24 hours after oophorectomy and they remained in this range for the 6 months of the study. No significant change in the plasma estrogen level was noted after oophorectomy in those patients who received an implant. The implant prevented the rise in gonadotropin levels and the appearance of vasomotor symptoms seen in those patients who underwent oophorectomy without an implant. Insertion of an implant into oophorectomized patients caused the plasma estrogen level to return to premenopausal levels within 2 weeks and the gonadotropin levels to premenopausal values within 6 weeks. Hot flashes were alleviated within 2 to 6 days. The usefulness of this type of therapy in preventing the appearance of vasomotor symptoms at the time of oophorectomy in premenopausal patients is confirmed.