Extrarenal Na+ balance, volume, and blood pressure homeostasis in intact and ovariectomized deoxycorticosterone-acetate salt rats

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Item Type:	Article
Title:	Extrarenal Na+ balance, volume, and blood pressure homeostasis in intact and ovariectomized deoxycorticosterone-acetate salt rats
Creators Name:	Titze, J., Luft, F.C., Bauer, K., Dietsch, P., Lang, R., Veelken, R., Wagner, H., Eckardt, K.U. and Hilgers, K.F.
Abstract:	Water-free Na storage may buffer extracellular volume and mean arterial pressure (MAP) in spite of Na retention. We studied the relationship among internal Na, K, water balance, and MAP in Sprague-Dawley rats, with or without deoxycorticosterone-acetate (DOCA) salt, with or without ovariectomy (OVX). The rats were fed a low-salt (0.1% NaCl) or high-salt (8% NaCl) diet for 5 weeks. DOCA salt increased MAP (161±14 versus 123±4 mm Hg; P<0.05), and DOCA-OVX salt increased MAP further (181±22 mm Hg; P<0.05). DOCA salt increased the total body Na by ≈40% to 45%; however, water-free Na retention by osmotically inactive Na storage and by osmotically neutral Na/K exchange allowed the rats to maintain the extracellular volume close to normal. DOCA-OVX salt rats showed similar Na retention. However, their osmotically inactive Na storage capacity was greatly reduced and only partially compensated by neutral Na/K exchange, resulting in greater volume retention despite similar Na retention. For every 1% wet weight total body water gain, MAP increased by 2.3±0.2 mm Hg in DOCA salt rats and 2.5±0.3 mm Hg in DOCA-OVX salt rats. Because water-free Na retention buffered total body water content by 8% to 11% wet weight, we conclude that this internal Na escape buffered MAP. Extrarenal Na and volume balance seem to play an important role in long-term volume and MAP control. © 2006 American Heart Association, Inc.
Keywords:	Blood Pressure, Desoxycorticosterone, Extracellular Fluid, Homeostasis, Hypertension, Ovariectomy, Potassium, Rats, Sodium, Sodium Chloride, Sprague-Dawley Rats, Water-Electrolyte Balance, Animals
Source:	Hypertension
ISSN:	0194-911X
Publisher:	American Heart Association
Volume:	47
Number:	6
Page Range:	1101-1107
Date:	June 2006
Official Publication:	https://doi.org/10.1161/01.HYP.0000221039.17735.1a
PubMed:	View item in PubMed

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