Details

Autor(en) / Beteiligte

• Titze, Jens
• Luft, Friedrich C
• Bauer, Katharina
• Dietsch, Peter
• Lang, Rainer
• Veelken, Roland
• Wagner, Hubertus
• Eckardt, Kai-Uwe
• Hilgers, Karl F

Titel

Extrarenal Na+ Balance, Volume, and Blood Pressure Homeostasis in Intact and Ovariectomized Deoxycorticosterone-Acetate Salt Rats

Ist Teil von

• Hypertension (Dallas, Tex. 1979), 2006-06, Vol.47 (6), p.1101-1107

Ort / Verlag

Philadelphia, PA: American Heart Association, Inc

Erscheinungsjahr

2006

Link zum Volltext

Quelle

MEDLINE

Beschreibungen/Notizen

• 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.