Effects of long-term low-dose hormone replacement therapy on the binding capacity of platelet peripheral-type benzodiazepine receptor in postmenopausal women

The effects of long-term low-dose hormone replacement therapy (HRT) on the level of hormone in plasma and on the binding capacity of peripheral-type benzodiazepine receptor (PBR) on the platelet membranes were investigated among women. This study was a retrospective and case-controlled study where 64 women using long-term low-dose HRT for over 4 years entered the study and 99 women, age and education matched, were enrolled as control. Plasma hormone level and platelet PBR binding capacity of two groups were analyzed. A significant increase in plasma estradiol level in women using HRT was observed, compared to those in the control group. Meanwhile, women in the HRT group displayed higher platelet PBR binding capacity. Further analysis demonstrated that the binding capacity of platelet PBR was closely related to estradiol plasma level in all subjects. These results suggest that long-term low-dose HRT could relieve the decrease of estradiol level in plasma and PBR binding capacity on platelets in postmenopausal women, alleviate the endocrine imbalance process, and might be beneficial for reducing the risks of some diseases. (C) 2008 Elsevier Ltd. All rights reserved.