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Differential effect of low and standard dose of conjugate equine estrogen treatment in mesenteric venular response to angiotensin II from ovariectomized spontaneously hypertensive rats
Author(s) -
Araujo Priscila Xavier,
Ceravolo Graziela Scalianti,
Costa Tiago Januário,
DoSantos Rosangela Aparecida,
Oliveira Maria Aparecida,
Akamine Eliana Hirome,
Cássia Tostes Rita,
Fortes Zuleica Bruno,
Carvalho Maria Helena Catelli
Publication year - 2012
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.26.1_supplement.840.4
Subject(s) - ovariectomized rat , medicine , endocrinology , estrogen , angiotensin ii , receptor
Controversy still exists whether estrogen hormonal therapy confers cardiovascular benefit or harm. The potential harm caused by standard dosages of estrogen including coronary heart disease and venous thromboembolism may be mitigated by use of lower doses. The aim of this study was evaluate the venular effect of conjugate equine estrogen (CEE) treatment, in ovariectomized (OVX) SHR, at standard therapeutic (SD) vs low dose (LD). For that, isolated mesenteric venular bed was perfused with angiotensin II (Ang II) in a concentration‐ dependent manner. Venular hyper reactivity to Ang II (maximal response), augmented ROS generation, reduced SOD, catalase activity and NO bioavailability were found in OVX and SD vs. control rats in physiological estrous and LD. On the other hand, the reduced MVB response to Ang II in LD rats was related to increased endothelial NO synthase activity, reduced ROS generation and increased Ang II AT2 receptor expression. We suggest that CEE at a low dose has a protective effect in OVX mesenteric venular bed. The standard therapeutic dose might increase the risk for venular disease by inducing alterations in venular reactivity.