Faqi A S, Sherman D D, Wang M, Pasquali M, Bayorh M A, Thierry-Palmer M
Department of Biochemistry, Morehouse School of Medicine, Atlanta, Georgia 30310-1495, USA.
Am J Med Sci. 2001 Dec;322(6):333-8. doi: 10.1097/00000441-200112000-00005.
We have shown previously that the calciuric response to salt does not differ in Dahl salt-sensitive (S) and salt-resistant (R) male rats. Clinical studies with women, however, suggest an effect of salt sensitivity on the calciuric response to salt. The objective of this study was to determine whether there is an effect of salt sensitivity on the calciuric response to salt of female S and R rats.
Dahl S and R female rats were fed high- (8%) or low- (0.3%) salt diets for 3 weeks. The rats were placed in metabolic cages for 24-hour urine collection at baseline and weekly (for sodium and calcium determination).
Blood pressure of female S rats was 177+/-3.0 mm Hg at week 3 of high salt intake compared with 96+/-1 mm Hg for female R rats. Female S rats excreted significantly more calcium than female R rats at baseline (P < 0.001), when fed a nonpurified diet, and during high salt intake (P = 0.004). Salt sensitivity significantly increased calcium excretion, water intake, and urine output when rats were fed a high-salt diet. Calcium excretion, water intake, and urine output of female S rats were time-dependent during high salt intake. Plasma 25-hydroxyvitamin D and 24,25-dihydroxyvitamin D concentrations were markedly lower in female S rats fed a high-salt diet, but not in female R rats. Plasma parathyroid hormone and 1,25-dihydroxyvitamin D concentrations did not significantly differ between female S and R rats, but plasma concentrations of these two hormones at week 3 were significantly higher in S rats fed a high-salt diet compared with S rats fed a low-salt diet.
Our data indicate that the calciuric response to salt is greater in female S compared with female R rats, thus supporting findings on the effect of salt sensitivity reported in several clinical studies with women. The greater calciuric response to salt of female S rats compared with female R rats, which was not seen in a previous study when male S rats were compared to male R rats, suggest a gender difference in the calciuric response to salt.
我们之前已经表明，Dahl盐敏感（S）和盐抵抗（R）雄性大鼠对盐的钙尿反应并无差异。然而，针对女性的临床研究表明，盐敏感性对盐的钙尿反应存在影响。本研究的目的是确定盐敏感性对雌性S和R大鼠盐的钙尿反应是否有影响。
给Dahl S和R雌性大鼠喂食高盐（8%）或低盐（0.3%）饮食3周。在基线时以及每周（用于测定钠和钙）将大鼠置于代谢笼中收集24小时尿液。
高盐摄入第3周时，雌性S大鼠的血压为177±3.0毫米汞柱，而雌性R大鼠为96±1毫米汞柱。在基线时（P<0.001）、喂食非纯化饮食时以及高盐摄入期间（P = 0.004），雌性S大鼠排泄的钙显著多于雌性R大鼠。当给大鼠喂食高盐饮食时，盐敏感性显著增加钙排泄、水摄入量和尿量。在高盐摄入期间，雌性S大鼠的钙排泄、水摄入量和尿量呈时间依赖性。喂食高盐饮食的雌性S大鼠血浆25-羟维生素D和24,25-二羟维生素D浓度明显较低，但雌性R大鼠并非如此。雌性S和R大鼠之间血浆甲状旁腺激素和1,25-二羟维生素D浓度无显著差异，但与喂食低盐饮食的S大鼠相比，喂食高盐饮食的S大鼠在第3周时这两种激素的血浆浓度显著更高。
我们的数据表明，与雌性R大鼠相比，雌性S大鼠对盐的钙尿反应更大，从而支持了几项针对女性的临床研究中报道的盐敏感性影响的研究结果。与雌性R大鼠相比，雌性S大鼠对盐的钙尿反应更大，这在之前比较雄性S大鼠和雄性R大鼠的研究中未观察到，提示在盐的钙尿反应中存在性别差异。
