17ss oestradiol does not attenuate the response to angiotensin I and II during long term therapy in postmenopausal women.
OBJECTIVE
It is thought that oestrogen replacement therapy may reduce the conversion of angiotensin I to angiotensin II in postmenopausal women by inhibiting angiotensin converting enzyme. We sought to determine the effects of 3 months oestrogen replacement therapy (ERT) on the response to angiotensin I and II in postmenopausal women.


METHODS
Eighteen postmenopausal women were randomised to either three months of 2 mg oral oestradiol or placebo in a double blind, placebo controlled, protocol. Change in forearm blood flow (FBF), in response to brachial arterial infusion of increasing concentrations of angiotensin I and angiotensin II was measured, pre-randomisation, after 1 months randomised therapy and after 3 months therapy, using venous occlusion plethysmography.


RESULTS
Oestrogen treatment had no effect on baseline FBF. The mean (SD) peak reductions in FBF with 64 pmol/min angiotensin I pre-randomisation, after 1 month and after 3 months treatment with placebo were 62(11), 65(15) and 57(8)%. The corresponding reductions with the peak dose of angiotensin II (16 pmol/min) were 53(8), 48(12) and 47(11)%. In the oestradiol group, the peak responses to angiotensin I were 56(8), 53(11) and 44(29)% pre-randomisation, after 1 months treatment and after 3 months treatment. The corresponding reductions in response to angiotensin II were 37(15), 47(15) and 45(19)%. Oestradiol did not affect the response to either angiotensin I or angiotensin II.


CONCLUSIONS
This study does not support the idea that ERT might exert a cardioprotective effect through inhibition of the renin-angiotensin system.
Jhund
Pardeep S
PS
Department of Cardiology, Western Infirmary, Glasgow, United Kingdom.
Dawson
Nuala
N
Davie
Andrew P
AP
Norrie
John
J
O'Kane
Kevin P J
KP
McMurray
John J V
JJ
D000803:Angiotensin I / Q000378:metabolism / Q000494:pharmacology*; D000804:Angiotensin II / Q000378:metabolism / Q000494:pharmacology*; D001783:Blood Flow Velocity / Q000187:drug effects; D004311:Double-Blind Method; D004958:Estradiol / Q000627:therapeutic use*; D015914:Estrogen Replacement Therapy; D005260:Female; D005542:Forearm / Q000098:blood supply; D006801:Humans; D008875:Middle Aged; D017698:Postmenopause; D014662:Vasoconstrictor Agents / Q000378:metabolism / Q000494:pharmacology*
D014662:Vasoconstrictor Agents; D000804:Angiotensin II; D004958:Estradiol; D000803:Angiotensin I