Effects of hormone replacement therapy on ambulatory blood pressure and vascular responses in normotensive women

Abstract

The effects of chronic oestrogen replacement therapy (ERT) (conjugated equine oestrogen 0.625 mg/day) and combined oestrogen and progestogen replacement therapy (HRT) (ERT plus continuous medroxyprogesterone acetate 5 mg/day) on 24-h ambulatory blood pressure recordings, forearm vascular resistance (FVR) and FVR responses to noradrenaline, angiotensin II, acetylcholine and nitroprusside were studied in 17 normotensive postmenopausal women in a 3-month randomized, double-blind, placebo-controlled crossover trial with 1 month of therapy in each treatment arm. During the last few days of each 1-month treatment period, the subjects underwent 24-h ambulatory blood pressure recordings and measurements of FVR responses. ERT and HRT reduced mean 24-h diastolic blood pressure by 4 and 5 mmHg, systolic blood pressure by 6 and 9 mmHg and mean 24-h heart rate by 5 and 3 beats/min, respectively for ERT and HRT (p < 0.05). Basal FVR was reduced by approximately 18% by ERT and HRT, but FVR responses to noradrenaline, angiotensin II, acetylcholine and nitroprusside were unaffected. ERT and HRT therapy for 1 month lowers blood pressure and basal FVR, but does not appear to influence FVR responses to acetylcholine, nitroprusside, noradrenaline and angiotensin II.