Zemel M B, Kraniak J, Standley P R, Sowers J R
Department of Nutrition and Food Science, Wayne State University, Detroit, Michigan 48201.
Am J Hypertens. 1988 Oct;1(4 Pt 1):386-92. doi: 10.1093/ajh/1.4.386.
The role of dietary salt and calcium on changes in cellular cation metabolism has been evaluated in 11 salt-sensitive hypertensive black adults maintained on the following four metabolic diets for 56 days, 14 days on each diet in a repeated measures format: 356 mg Ca-1000 mg sodium (NA); 356 mg Ca-4000 mg Na; 934 Ca-1000 mg Na; and 934 mg Ca-4000 mg Na. Increasing dietary Na at the lower Ca intake caused significant (P less than 0.05) increases in parathyroid hormone (PTH) and 24-hour cyclic AMP excretion that were associated with significant (P less than 0.01) increases in erythrocyte intracellular calcium (from 5.4 +/- 0.7 to 11.1 +/- 3.7 microM), Ca-ATPase (from 37.2 +/- 2.4 to 42.2 +/- 2.1 pmol/min/10(6) cells) and intracellular sodium (from 220.5 +/- 7.4 to 262.0 +/- 8.3 micrograms/mL) and decreases (P less than 0.05) in Na/K-ATPase (from 1.90 +/- 0.55 to 1.48 +/- 0.47 pmol/min/10(6) cells) and intracellular magnesium (Mg) (from 52.4 +/- 3.5 to 43.8 +/- 2.4 micrograms/mL). Adding calcium to this high sodium diet reversed these effects, whereas adding calcium to the low sodium diet was without significant effect. These results indicate that dietary salt causes increases in intracellular sodium and calcium and that the antihypertensive effect of dietary calcium in salt-sensitive individuals may be attributable in part to preventing this salt-induced elevation in intracellular calcium. This increase in intracellular calcium could be due to the observed increase in PTH levels or to the salt-induced reduction in intracellular magnesium that appears to suppress Na/K-ATPase and thereby increases intracellular sodium.
在11名盐敏感型高血压黑人成年人中，评估了膳食盐和钙对细胞阳离子代谢变化的作用。这些受试者按照以下四种代谢饮食方案维持56天，每种饮食方案持续14天，采用重复测量的形式：356毫克钙 - 1000毫克钠（钠）；356毫克钙 - 4000毫克钠；934毫克钙 - 1000毫克钠；以及934毫克钙 - 4000毫克钠。在较低钙摄入量的情况下增加膳食钠会导致甲状旁腺激素（PTH）和24小时环磷酸腺苷排泄量显著（P小于0.05）增加，这与红细胞细胞内钙显著（P小于0.01）增加（从5.4±0.7微摩尔增加到11.1±3.7微摩尔）、钙 - 腺苷三磷酸酶（Ca - ATPase）（从37.2±2.4皮摩尔/分钟/10⁶个细胞增加到42.2±2.1皮摩尔/分钟/10⁶个细胞）以及细胞内钠（从220.5±7.4微克/毫升增加到262.0±8.3微克/毫升）相关，同时钠/钾 - 腺苷三磷酸酶（Na/K - ATPase）（从1.90±0.55皮摩尔/分钟/10⁶个细胞减少到1.48±0.47皮摩尔/分钟/10⁶个细胞）和细胞内镁（Mg）（从52.4±3.5微克/毫升减少到43.8±2.4微克/毫升）减少（P小于0.05）。在这种高钠饮食中添加钙可逆转这些影响，而在低钠饮食中添加钙则无显著效果。这些结果表明，膳食盐会导致细胞内钠和钙增加，并且膳食钙对盐敏感个体的降压作用可能部分归因于防止这种盐诱导的细胞内钙升高。细胞内钙的这种增加可能是由于观察到的PTH水平升高，或者是由于盐诱导的细胞内镁减少，而细胞内镁减少似乎会抑制Na/K - ATPase，从而增加细胞内钠。
