Lijnen P, Petrov V
Department of Molecular and Cardiovascular Research, University of Leuven, Belgium.
J Hypertens. 1995 Aug;13(8):875-82. doi: 10.1097/00004872-199508000-00008.
A double-blind, placebo-controlled parallel-group study was conducted on the effect of a high level of daily oral calcium supplementation (1 g elemental calcium given twice a day for 16 weeks) in normal male subjects on blood pressure, intracellular cationic concentrations and transmembrane cation transport systems, plasma total and ionized calcium, and calciotropic hormones.
After a 1-month run-in period with a limited intake of dairy products, the 32 subjects were allocated to a placebo or a calcium group. Placebo or 1 g elemental calcium was administered twice a day, in the morning and evening, for 16 weeks. All subjects were investigated at baseline and after 1, 2, 4, 8 and 16 weeks of placebo or calcium administration.
Compared with the placebo group, standing systolic blood pressure was decreased in the calcium group, whereas the standing diastolic blood pressure tended to decrease. The changes in supine systolic and diastolic blood pressure did not differ between the placebo and calcium groups. Decreased intra-erythrocyte and intraplatelet sodium and calcium concentrations, an increased activity of platelet and erythrocyte sodium-pump activity and a reduced membrane cholesterol content were observed in the calcium-treated subjects. Erythrocyte membrane surface and core microviscosity, however, did not change during calcium supplementation. Oral calcium supplementation in these men was accompanied by a reduction in the plasma concentrations of intact parathormone and 1,25-dihydroxyvitamin D3, and an increase in 24 h urinary calcium excretion, but no change in the plasma total calcium concentration, serum ionized calcium level, or plasma phosphate or 25-hydroxyvitamin D3. The intra-erythrocyte and intraplatelet potassium and magnesium concentrations as well as the activities of the erythrocyte Na,Li-countertransporter and Na,K-cotransporter, and sodium and potassium leakage did not change during calcium administration.
The lowering of standing blood pressure seen in men with a high calcium intake is accompanied by a decrease in cytosolic free platelet calcium and total erythrocyte calcium, by a reduction in intraplatelet and intra-erythrocyte sodium concentration and erythrocyte membrane cholesterol and by an increase in the activity of the erythrocyte and platelet sodium-pump.
开展一项双盲、安慰剂对照平行组研究，以探讨正常男性受试者每日口服高剂量钙补充剂（每天两次，每次1克元素钙，共16周）对血压、细胞内阳离子浓度和跨膜阳离子转运系统、血浆总钙和离子钙以及钙调节激素的影响。
在为期1个月的乳制品摄入量受限的导入期后，将32名受试者分为安慰剂组或钙组。安慰剂或1克元素钙每天早晚各服用一次，持续16周。所有受试者在基线时以及服用安慰剂或钙1、2、4、8和16周后均接受调查。
与安慰剂组相比，钙组的站立位收缩压降低，而站立位舒张压有降低趋势。安慰剂组和钙组仰卧位收缩压和舒张压的变化无差异。在接受钙治疗的受试者中，观察到红细胞内和血小板内钠和钙浓度降低，血小板和红细胞钠泵活性增加，膜胆固醇含量降低。然而，在补钙期间红细胞膜表面和核心微粘度没有变化。这些男性口服钙补充剂后，血浆完整甲状旁腺激素和1,25 - 二羟维生素D3浓度降低，24小时尿钙排泄增加，但血浆总钙浓度、血清离子钙水平、血浆磷酸盐或25 - 羟维生素D3无变化。补钙期间红细胞内和血小板内钾和镁浓度以及红细胞钠 - 锂逆向转运体和钠 - 钾协同转运体的活性以及钠和钾泄漏均无变化。
高钙摄入量男性出现的站立位血压降低伴随着胞质游离血小板钙和总红细胞钙减少、血小板内和红细胞内钠浓度降低、红细胞膜胆固醇减少以及红细胞和血小板钠泵活性增加。
