Iwaoka T, Umeda T, Miura F, Inoue J, Sasaki M, Naomi S, Sato T
Third Department of Internal Medicine, Kumamoto University Medical School, Japan.
J Hypertens. 1991 Jan;9(1):49-54.
To investigate the mechanism whereby blood pressure rises with NaCl loading in salt-sensitive essential hypertension, salt-sensitivity index was determined along with sodium and lithium clearances, plasma Na+,K(+)-ATPase inhibitor and intra-erythrocyte sodium and potassium concentrations. Salt-sensitivity index was defined as the percentage of change in mean blood pressure when NaCl intake was changed from low (34 mmol/day) to high (342 mmol/day). Salt-sensitivity index was inversely correlated with fractional excretion of lithium both on the low and high NaCl diets (r = -0.721, P less than 0.01 and r = -0.591, P less than 0.02, respectively; n = 16), but not with fractional excretion of sodium. The change of plasma Na+,K(+)-ATPase inhibition with NaCl loading had a direct correlation with salt-sensitivity index (r = 0.704, P less than 0.01; n = 16). Either intra-erythrocyte sodium and potassium concentrations or the ratio of these two values did not change significantly with an increase of dietary NaCl intake. These results suggest that an enhancement of proximal tubular sodium reabsorption stimulates secretion of plasma Na+,K(+)-ATPase inhibitor which may be involved in a rise in blood pressure with sodium loading. They also suggest that lithium clearance is a determinant which can predict salt sensitivity without actual NaCl loading.
为研究盐敏感性原发性高血压患者中血压随氯化钠摄入量增加而升高的机制，我们测定了盐敏感性指数以及钠和锂清除率、血浆钠钾ATP酶抑制剂、红细胞内钠和钾浓度。盐敏感性指数定义为氯化钠摄入量从低（34 mmol/天）变为高（342 mmol/天）时平均血压的变化百分比。在低氯化钠饮食和高氯化钠饮食中，盐敏感性指数均与锂的排泄分数呈负相关（分别为r = -0.721，P < 0.01和r = -0.591，P < 0.02；n = 16），但与钠的排泄分数无关。随着氯化钠摄入量增加，血浆钠钾ATP酶抑制作用的变化与盐敏感性指数呈正相关（r = 0.704，P < 0.01；n = 16）。随着饮食中氯化钠摄入量的增加，红细胞内钠和钾浓度或这两个值的比值均无显著变化。这些结果表明，近端肾小管钠重吸收增强会刺激血浆钠钾ATP酶抑制剂的分泌，这可能与钠负荷增加导致的血压升高有关。它们还表明，锂清除率是一个决定因素，可在无实际氯化钠负荷的情况下预测盐敏感性。
