Angiotensin II plays an important role in maintaining blood pressure in postmenopausal women receiving hormone replacement therapy.
BACKGROUND
We investigated the role of angiotensin (Ang) II in maintaining blood pressure (BP) by administering a small dose of candesartan, an Ang II type 1 receptor antagonist, in postmenopausal women receiving long-term hormone replacement therapy (HRT).


METHODS
A single dose of 2 mg of candesartan was administered orally to 13 normotensive postmenopausal women receiving HRT (continuous combined conjugated estrogen and medroxyprogesterone acetate orally; HRT group) and 13 normotensive postmenopausal women not receiving HRT (control group). Both BP and heart rate (HR) were measured at baseline and at 1, 2, 3, 4, 5, and 6 h after administration. Plasma renin activity (PRA) and Ang I, Ang II, and bradykinin concentrations were measured at baseline and 4 h after the administration of candesartan.


RESULTS
Candesartan lowered the BP and raised the HR in both groups. However, the decrease in BP was significantly greater in the HRT group than in the control group (P < .05), whereas no significant difference in the change in HR was observed between the two groups. In the HRT group, significant increases were found in PRA, Ang I, and Ang II (all P < .05) and a significant decrease in bradykinin (P < .01) with candesartan treatment. In the control group, candesartan as associated with an increase in PRA (P < .05) but not in Ang I, Ang II, or bradykinin.


CONCLUSIONS
Based on our study results, Ang II plays an important role in maintaining BP in normotensive postmenopausal women receiving HRT. Maintenance of BP may be dependent on the balance between the hypertensive effect of Ang II and the hypotensive effect of bradykinin.
Sumino
Hiroyuki
H
Second Department of Internal Medicine, Gunma University School of Medicine, Maebashi, Japan. suminoh@med.gunma-u.ac.jp
Ichikawa
Shuichi
S
Miya
Yoshinori
Y
Sakamaki
Tetsuo
T
Kurabayashi
Masahiko
M
D000284:Administration, Oral; D000450:Aldosterone / Q000097:blood; D000803:Angiotensin I / Q000097:blood; D000804:Angiotensin II / Q000097:blood / Q000502:physiology*; D047228:Angiotensin II Type 1 Receptor Blockers / Q000008:administration & dosage / Q000627:therapeutic use; D000959:Antihypertensive Agents / Q000627:therapeutic use; D001562:Benzimidazoles / Q000008:administration & dosage / Q000097:blood / Q000627:therapeutic use; D015415:Biomarkers / Q000097:blood; D001713:Biphenyl Compounds; D001794:Blood Pressure / Q000187:drug effects*; D001920:Bradykinin / Q000097:blood; D004359:Drug Therapy, Combination; D004837:Epinephrine / Q000097:blood; D004967:Estrogens / Q000008:administration & dosage / Q000627:therapeutic use*; D005260:Female; D006339:Heart Rate / Q000187:drug effects; D020249:Hormone Replacement Therapy; D006801:Humans; D008875:Middle Aged; D009638:Norepinephrine / Q000097:blood; D007703:Peptidyl-Dipeptidase A / Q000097:blood; D017698:Postmenopause; D012083:Renin / Q000097:blood; D013777:Tetrazoles / Q000008:administration & dosage / Q000097:blood / Q000627:therapeutic use; D016896:Treatment Outcome
D047228:Angiotensin II Type 1 Receptor Blockers; D000959:Antihypertensive Agents; D001562:Benzimidazoles; D015415:Biomarkers; D001713:Biphenyl Compounds; D004967:Estrogens; D013777:Tetrazoles; D000804:Angiotensin II; D000450:Aldosterone; D000803:Angiotensin I; D007703:Peptidyl-Dipeptidase A; D012083:Renin; C081643:candesartan; D001920:Bradykinin; D009638:Norepinephrine; D004837:Epinephrine