Hormone replacement therapy in postmenopausal women with essential hypertension increases circulating plasma levels of bradykinin

Hormone replacement therapy (HRT) reduces the incidence of cardiovascular d isease (CVD) in postmenopausal women (PMW). Recently, it has been reported that HRT declines angiotensin converting enzyme (ACE) activity, which may b e one of the factors protecting against CVD. We measured the plasma levels of bradykinin, which would be expected to increase because the bradykinin-d egrading enzyme (kinase II) is the same as ACE. Treatment with conjugated e strogens (0.625 mg/day) and medroxyprogesterone (2.5 mg/ day) was given for 3 months as HRT to 19 hypertensive and 19 normotensive PMW. Plasma bradyki nin and ACE activity levels were measured at baseline and after 3 months of HRT. The plasma levels of ACE activity in both the hypertensive and normot ensive PMW were significantly reduced by HRT. The plasma levels of bradykin in in the hypertensive PMW were significantly increased by HRT, whereas the administration of HRT tended to increase plasma levels of bradykinin in th e normotensive PMW. The increased bradykinin levels with a concomitant decr ease of plasma ACE activity by HRT in hypertensive PMW seem to be beneficia l for reducing the risk of CVD. (C) 1999 American Journal of Hypertension, Ltd.