Postmenopausal hypertension: role of the Renin-Angiotensin system.
After menopause, blood pressure increases in women. However, the underlying mechanisms responsible for postmenopausal hypertension are not completely understood. This study was conducted to determine the role that the renin-angiotensin system (RAS) plays in post-menopausal hypertension. Post-estrous cycling (postmenopausal) spontaneously hypertensive rats or young female controls were treated with losartan, an angiotensin (Ang) II type 1 receptor blocker, for 25 days. Mean arterial pressure was recorded continuously by radiotelemetry. Losartan significantly decreased blood pressure in postmenopausal rats and young female controls but failed to normalize blood pressure in postmenopausal rats to levels found in young controls. Plasma renin activity and plasma angiotensinogen were significantly elevated, and intrarenal Ang II type 1 receptor and renin mRNA expression were significantly downregulated in postmenopausal rats. Therefore, RAS only partially contributes to hypertension in postcycling spontaneously hypertensive rats, whereas hypertension in young females is mediated mainly by the RAS. The data suggest that other mechanisms besides activation of the RAS are likely involved in postmenopausal hypertension.
Yanes
Licy L
LL
Department of Physiology and Biophysics, University of Mississippi Medical Center, 2500 N State Street, Jackson, MS 39216-4505, USA.
Romero
Damian G
DG
Iliescu
Radu
R
Zhang
Huimin
H
Davis
Deborah
D
Reckelhoff
Jane F
JF
D000704:Analysis of Variance; D047228:Angiotensin II Type 1 Receptor Blockers / Q000494:pharmacology; D000808:Angiotensinogen / Q000235:genetics / Q000378:metabolism; D000818:Animals; D001794:Blood Pressure / Q000187:drug effects; D005260:Female; D006973:Hypertension / Q000235:genetics / Q000378:metabolism / Q000503:physiopathology*; D007668:Kidney / Q000187:drug effects / Q000378:metabolism / Q000503:physiopathology; D019808:Losartan / Q000494:pharmacology*; D007703:Peptidyl-Dipeptidase A / Q000235:genetics / Q000378:metabolism; D051381:Rats; D011918:Rats, Inbred SHR; D012083:Renin / Q000235:genetics / Q000378:metabolism; D012084:Renin-Angiotensin System / Q000187:drug effects / Q000502:physiology*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013686:Telemetry
D047228:Angiotensin II Type 1 Receptor Blockers; D000808:Angiotensinogen; D007703:Peptidyl-Dipeptidase A; D012083:Renin; D019808:Losartan