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Estradiol Replacement Attenuates Central Body Fluid Regulatory Responses to Hyperosmolality and Central Angiotensin II in Ovariectomized Rats
Author(s) -
Omura Natsumi,
Nishimura Yuri,
Igarashi Ayako,
Takamata Akira
Publication year - 2015
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.29.1_supplement.658.2
Subject(s) - endocrinology , medicine , subfornical organ , supraoptic nucleus , angiotensin ii , ovariectomized rat , circumventricular organs , hypothalamus , median preoptic nucleus , hypertonic saline , angiotensin ii receptor type 1 , chemistry , estrogen receptor , vasopressin , estrogen , angiotensin receptor , receptor , biology , cancer , breast cancer
Estrogen replacement reportedly attenuates the drinking response to systemic hypertonic saline infusion and i.c.v. angiotensin II (ANGII) administration in ovariectomized rats. In order to elucidate the site of the action of estradiol, we examined the effect of estradiol replacement on c‐Fos expression in the circumventricular organs (CVOs), and vesopressinergic neurons in the supraoptic nucleus (SON) and paraventricular nucleus (PVN) in response to systemic hypertonic saline and i.c.v. ANGII administrations in ovariectomized rats. We also examined ANGII type I (AT1) receptor expression in the hypothalamus and kidney by use of Western blotting in estradiol replaced and not replaced ovariectomized rats. Estradiol replacement attenuated c‐Fos expression at the organum vasclosam laminar terminalis (OVLT), supraoptic nucleus (SON) and paraventricular nucleus (PVN) in response to systemic hypertonic saline infusion, and also attenuated c‐Fos expression at the OVLT, subfornical organ, median preoptic nucleus, SON and PVN after i.c.v. ANGII administration. We also found that the AT1 receptor expression in the hypothalamus and kidney was less in estradiol‐replaced rats than estrogen deficit rats. Our data suggest that estradiol possibly attenuates AT1 receptor expression in the hypothalamus, and the attenuated AT1 receptor expression may be involved in the attenuated body fluid regulatory responses to systemic hyperosmolality and central ANGII.