Type of Document	Dissertation
Author	Krause, Eric Gerald
URN	etd-10252005-123505
Title	Estrogen, Fluid Balance, and Cardiovascular Regulation: an Estrogen-Angiotensin Interaction?
Degree	Doctor of Philosophy
Department	Psychology, Department of
Advisory Committee	Advisor Name Title Robert Contreras Committee Chair Kathleen Curtis Committee Member Lisa Eckel Committee Member Marc Freeman Committee Member Mike Overton Committee Member Thomas Joiner Committee Member Zuoxin Wang Committee Member
Keywords	Baroreflex Water Intake Renin Angiotensin II
Date of Defense	2005-10-21
Availability	unrestricted
Abstract The goal of this study was to evaluate the effects of estrogen on cardiovascular regulation and fluid balance, while also controlling for body weight changes that occur as a consequence of ovariectomy and estrogen replacement. In terms of cardiovascular regulation, estrogen significantly attenuated the depressor response to isoproterenol (ISOP) and this reduction was accompanied by an increase in HR similar to those of rats in which mean arterial pressure (MAP) decreased nearly two-fold more. Furthermore, estrogen treatment significantly reduced ISOP-elicited Fos immunoreactivity (IR) in the area postrema and lateral parabrachial nucleus, both of which are important components of a hindbrain circuit that regulates cardiovascular reflexes. In terms of fluid balance, estrogem and weight loss decreased Fos IR and angiotensin type 1 receptor mRNA in the subfornical organ when compared to the oil treated controls rats. In addition, despite similar plasma renin activity, weight loss treated rats consumed about half the amount of water as did oil treated rats after ISOP, intakes that were very similar to those of estrogen and oil treated rats in our previous study. Thus, estrogen alone alters activity in hindbrain circuits governing cardiovascular reflexes, which may underlie estrogen-mediated attenuation of the depressor response to ISOP. Conversely, both estrogen and weight loss had similar effects on the subfornical organ, a forebrain structure implicated in the control of angiotensin II-mediated water intake, suggesting that the weight loss that accompanies estrogen replacement underlies estrogen affects on angiotensin II stimulated water intake.
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