The renin-angiotensin-aldosterone system plays a major role in the pathogenesis of hypertension by enhancing the production or the activity of angiotensin II (ANG II). We evaluated the effects of hormone replacement therapy (HRT) on the renin-angiotensin-aldosterone system and on bradykinin in postmenopausal women (PMW) who were hypertensive or normotensive. Subjects included 28 PMW whose elevated blood pressure (BP) was well controlled on antihypertensive agents excluding diuretics, angiotensin-converting enzyme (ACE) inhibitors, and ANG II receptor antagonists. As controls, we evaluated 16 normotensive PMW. All subjects received oral HRT daily for 6 months. The plasma levels of angiotensin I (ANG I), ANG II, and bradykinin as well as plasma renin activity (PRA) showed a significant increase in HRT in the hypertensive group, but not in the normotensive group. The serum ACE activity showed a significant decrease in both groups, but the plasma level of aldosterone was unchanged. Despite the decrease in serum ACE activity, there was an increase in the plasma ANG II level. Hormone replacement therapy increased the level of ANG II in the hypertensive women, but their BP was unaffected. The increase in plasma bradykinin level may maintain homeostasis in the presence of an increase in plasma ANG II, which is a risk factor for cardiovascular disease. Hormone replacement therapy was associated with a decrease in serum ACE and an increase in plasma bradykinin in hypertensive PMW. Accordingly, the protective effect of HRT against cardiovascular disease in PMW can be provided by a decrease in ACE activity and an increase in bradykinin.

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Objects: To investigate the effect of combined estrogen and progesterone therapy on insulin resistance (IR) and carbohydrate and lipid metabolism in postmenopausal women (PMW) with impaired (IGT) and normal glucose tolerance (NGT). Methods: Sixteen Japanese PMW with IGT and 33 with NGT received daily oral hormone replacement therapy (HRT; 0.625 mg of conjugated equine estrogen plus 2.5 mg of medroxyprogesterone acetate) for 12 months. As controls, 13 Japanese PMW with IGT and 31 with NGT were enrolled and not treated by HRT. Fasting plasma glucose (FPG), fasting immunoreactive insulin (IRI), and IR were measured in each subject at study initiation and 12 months later. We used homeostasis model assessment (HOMA) to determine IR. Results: FPG and HOMA IR were decreased in both HRT groups, and fasting IRI was reduced in the HRT-NGT group. In controls, FPG, fasting IRI, and HOMA IR were unaltered. Total and low-density lipoprotein cholesterol were decreased and high-density lipoprotein cholesterol was increased in both HRT groups, but triglyceride was unchanged. In controls, lipid metabolism was unaltered. Conclusion: HRT decreased IR and improved carbohydrate and lipid metabolism in Japanese PMW with IGT and NGT. These beneficial effects argue for the use of HRT in PMW with IGT as well as NGT.