Takada T, Nakagawa M, Ura N, Kaide J, Yoshida H, Shimamoto K
Second Department of Internal Medicine, Sapporo Medical University School of Medicine, Japan.
Hypertens Res. 1998 Sep;21(3):193-9. doi: 10.1291/hypres.21.193.
We evaluated the urinary excretion of immunoreactive endogenous ouabain-like factor (OLF) and digoxin-like factor (DLF) to investigate their pathophysiological roles in sodium metabolism and blood pressure in 5/6-reduced renal mass rats, a model of volume-expanded hypertension. About five-sixths of the kidney mass (5/6 RRM, n = 9) was removed from male Sprague-Dawley rats, or the rats were sham operated (control, n = 10). Both groups were fed regular diets with tap water for 1 wk as a control period, followed by 1% saline solution for 4 wk. Systolic blood pressure (SBP), urine volume (UV), urinary sodium excretion (UNaV), DLF, and OLF were measured on the last 2 d of every week throughout the experimental period. SBP and UNaV were significantly higher in 5/6 RRM rats than in control rats. Urinary DLF significantly increased, reaching peak value in the first week, while OLF increased continuously, reaching peak value in the fourth week. In the first week, there were a significant positive correlations between the change in DLF and the changes in UNaV and SBP. However, the change in OLF was not correlated with changes in either UNaV or SBP. Both SBP and UNaV showed a significant positive correlation with OLF (p<0.001, r=0.547, p<0.001, r=0.658, respectively), whereas DLF significantly correlated with UNaV (p< 0.001, r= 0.584) but not with SBP in 5/6 RRM. These findings suggest that endogenous OLF and DLF coexist in rat urine and that an increased level of OLF, but not DLF, may contribute to the development and maintenance of hypertension. DLF may contribute to renal sodium excretion in this volume-expanded hypertensive rat model.
我们评估了免疫反应性内源性哇巴因样因子（OLF）和地高辛样因子（DLF）的尿排泄情况，以研究它们在5/6肾切除大鼠（一种容量扩张性高血压模型）的钠代谢和血压中的病理生理作用。从雄性Sprague-Dawley大鼠中切除约六分之五的肾脏质量（5/6 RRM，n = 9），或对大鼠进行假手术（对照组，n = 10）。两组均在作为对照期的1周内给予常规饮食和自来水，随后给予1%盐溶液4周。在整个实验期间，每周的最后2天测量收缩压（SBP）、尿量（UV）、尿钠排泄量（UNaV）、DLF和OLF。5/6 RRM大鼠的SBP和UNaV显著高于对照组大鼠。尿DLF显著增加，在第一周达到峰值，而OLF持续增加，在第四周达到峰值。在第一周，DLF的变化与UNaV和SBP的变化之间存在显著正相关。然而，OLF的变化与UNaV或SBP的变化均无相关性。在5/6 RRM中，SBP和UNaV与OLF均呈显著正相关（分别为p<0.001，r = 0.547；p<0.001，r = 0.658），而DLF与UNaV显著相关（p<0.001，r = 0.584），但与SBP无相关性。这些发现表明，内源性OLF和DLF共存于大鼠尿液中，并且OLF水平升高而非DLF水平升高可能有助于高血压的发生和维持。在这个容量扩张性高血压大鼠模型中，DLF可能有助于肾钠排泄。
