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Effect of Age and Estrogen on the Contribution of Angiotensin to Salt Sensitive Hypertension
Author(s) -
HinojosaLaborde Carmen,
Masters Olivia,
Mehring Cynthia,
Craig Teresa
Publication year - 2006
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.20.4.a754-d
Subject(s) - medicine , ovariectomized rat , endocrinology , blockade , angiotensin ii , renin–angiotensin system , estrogen , blood pressure , estrogen replacement therapy , estrogen receptor , receptor , cancer , breast cancer
We have reported that both age and estrogen (E) modulate mean arterial pressure (MAP) in Dahl salt‐sensitive (DSS) female rats. MAP steadily increases in female DSS rats as they age despite a diet low in sodium. E replacement in ovariectomized (OVX) young (4 month old) and middle‐age (12 month old) DSS rats attenuates the development of hypertension. The purpose of this study was to evaluate the effects of age and E on the activation of the renin angiotensin system. We compared the effects of angiotensin type 1 receptor blockade with ZD7155 (ZD) in young (Y), and middle‐age (M) female DSS rats (SS/JR, Harlan Sprague Dawley) fed a low salt diet (0.1% NaCl, Teklad). Rats were implanted with radio telemetry transmitters for monitoring MAP, and subjected to OVX, OVX with E replacement (OVX+E), or sham surgery (Intact). Eight weeks after OVX/sham surgery, the rats were given ZD (1mg/kg, po.) for 7 days. Data are shown as mean ± SEM, * denotes significantly different from Intact and OVX, # denote significant different from Y group p<0.05.All groups of M rats had significantly greater responses to ZD than Y rats. We observed that OVX in both Y and M rats resulted in higher MAP and greater response to ZD; however this difference was not statistically significant. Replacement with E significantly attenuated the hypertension and diminished the response to ZD in both Y and M rats. We conclude that aging augments, and estrogen replacement attenuates the contribution of angiotensin II to blood pressure in female DSS rats on low salt diet. Supported by NIH/NIA AG20256.