Plasma ouabain-like factor during acute and chronic changes in sodium balance in essential hypertension.

Abstract

An ouabain-like factor has been implicated repeatedly in salt-sensitive hypertension as a natriuretic agent. However, the response of plasma ouabain-like factor to acute and chronic variation of body sodium is unclear. We studied 138 patients with essential hypertension who underwent an acute volume expansion/contraction maneuver (2 days) and 20 patients who entered a blind randomized crossover design involving chronically controlled sodium intake and depletion (170 to 70 mmol/d; 2 weeks each period). In both studies, plasma levels of ouabain-like factor were higher during sodium depletion (acute: 338.8+/-17.4 and 402.7+/-22.8 pmol/L for baseline and low sodium, respectively, P<0.01; chronic: 320.4+/-32.0 versus 481.0+/-48.1 pmol/L, P=0.01). No significant change in plasma ouabain-like factor was observed after a 2-hour saline infusion (333.4+/-23.9 pmol/L) or controlled sodium (402.1+/-34.9 pmol/L). When patients were divided into salt-sensitive or salt-resistant groups, no differences in plasma ouabain-like factor were observed in the 2 groups at baseline or in response to the 2 protocols: salt resistant (n=69, 340.1+/-25.9 pmol/L) versus salt sensitive (n=69, 337.4+/-23.6 pmol/L) and chronic salt resistant (n=11, 336.0+/-53.2) versus salt sensitive (n=9, 301.1+/-331.4 pmol/L). However, circulating ouabain-like factor was increased by sodium depletion in both groups. These results demonstrate that circulating ouabain-like factor is raised specifically by maneuvers that promote the loss of body sodium. Acute expansion of body fluids with isotonic saline is not a stimulus to plasma ouabain-like factor. Moreover, basal levels of plasma ouabain-like factor do not differ among patients with salt-sensitive or salt-resistant hypertension. Taken together, these new results suggest that ouabain-like factor is involved in the adaptation of humans to sodium depletion and argue against the hypothesis that ouabain-like factor is a natriuretic hormone.

• Authors: P Manunta, E Messaggio, C Ballabeni, M T Sciarrone, C Lanzani, M Ferrandi, J M Hamlyn, D Cusi, F Galletti, G Bianchi, Salt Sensitivity Study Group of the Italian Society of Hypertension
• Journal: Hypertension (Dallas, Tex. : 1979) (Hypertension) Vol. 38 Issue 2 Pg. 198-203 (Aug 2001) ISSN: 1524-4563 [Electronic] United States
• PMID: 11509476 (Publication Type: Clinical Trial, Journal Article, Randomized Controlled Trial, Research Support, Non-U.S. Gov't, Research Support, U.S. Gov't, P.H.S.)

Chemical References

• Cardenolides
• Saponins
• digoxin-like factors
• Digoxin
• Sodium
• Renin

Topics

• Adult
• Blood Pressure
• Cardenolides
• Cross-Over Studies
• Digoxin
• Female
• Humans
• Hypertension (blood, metabolism, physiopathology)
• Male
• Renin (blood)
• Saponins (blood)
• Sodium (metabolism)