Erythrocyte Sodium Ion Transport Systems in DOCA-Salt, Goldblatt, and Spontaneously Hypertensive Rats

1. The purpose of this study was to determine the effect of dietary Ca2+ intake on blood pressure and erythrocyte Na+ transport in spontaneously hypertensive rats. 2. Spontaneously hypertensive rats and Wistar-Kyoto rats were fed diets with three different Ca2+ contents, 0.1% (low-Ca2+ diet), 0.6% (normal-Ca2+ diet) and 4.0% (high-Ca2+ diet), between 6 and 20 weeks of age. At 20 weeks of age, the levels of erythrocyte Na+ efflux, as well as Na+ and K+ contents in erythrocytes, were measured. 3. On the low-Ca2+ diet, spontaneously hypertensive rats showed an enhancement of hypertension. Conversely, on the high-Ca2+ diet, they showed an attenuation of the increase in blood pressure. Spontaneously hypertensive rats had a lower erythrocyte Na+ content and increased activity of the Na+ pump at higher levels of dietary Ca2+. Passive Na+ permeability and Na+-K+ co-transport were similar in spontaneously hypertensive rats on the low-, normal- and high-Ca2+ diets. There were no significant differences in blood pressure and in Na+ pump activity in WKY on the three different diets. 4. It is concluded that dietary Ca2+ might affect the regulation of blood pressure in spontaneously hypertensive rats by changing the activity of Na+ pump in the cell membrane.

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Intra-Erythrocyte Sodium and (Na+,K+-Activated)-ATPase Concentration and Urinary Aldosterone Excretion in Spontaneously Hypertensive Rats

Clinical Science ◽

10.1042/cs0600229 ◽

1981 ◽

Vol 60 (2) ◽

pp. 229-232 ◽

Cited By ~ 13

Author(s):

G. Berglund ◽

L. Sigström ◽

S. Lundin ◽

B. E. Karlberg ◽

H. Herlitz

Keyword(s):

Spontaneously Hypertensive Rats ◽

Sodium Concentration ◽

Intracellular Sodium ◽

Hypertensive Rats ◽

Spontaneously Hypertensive ◽

Wistar Kyoto Rats ◽

Significant Difference ◽

Intracellular Sodium Concentration ◽

Erythrocyte Sodium ◽

Wistar Kyoto

1. Intra-erythrocyte sodium, potassium, ATP and (Na+,K+-activated)-ATPase concentrations and urinary aldosterone excretion were compared in 3-month-old spontaneously hypertensive rats (n = 11) and normotensive Wistar-Kyoto control rats (n = 11). 2. Spontaneously hypertensive rats exhibited significantly higher intra-erythrocyte sodium concentration (5.5 ± 1.3 vs 4.0 ± 1.1 mmol/l of erythrocytes, P < 0.01). No significant difference was found in intra-erythrocyte potassium, ATP or (Na+,K+-activated)-ATPase concentration. 3. Mean urinary aldosterone excretion was significantly lower in spontaneously hypertensive rats (66.3 ± 6.5 pmol/24 h) than in Wistar-Kyoto rats (90.5 ± 10.6 pmol/24 h, P < 0.01). No significant relationship between urinary aldosterone and intra-erythrocyte sodium concentration was found in spontaneously hypertensive or Wistar-Kyoto rats or in the pooled group. 4. These results are thus consistent with previous findings of an increased intracellular sodium concentration in spontaneously hypertensive rats, but do not support the hypothesis that aldosterone is a dominant regulator of intracellular sodium concentration.

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