Ornt D B, Radke K J, Scandling J D
Department of Medicine, School of Nursing, University of Rochester, New York 14642, USA.
Am J Physiol. 1996 Jun;270(6 Pt 1):E1003-8. doi: 10.1152/ajpendo.1996.270.6.E1003.
The importance of reduced plasma aldosterone concentration (PAC) in renal potassium (K) conservation is unclear. Thus we examined the effect of aldosterone on incipient, developing, and established renal K conservation. Adrenalectomized (ADX) dexamethasone-replaced rats were continuously treated with high, normal, or low dosages of aldosterone during 4 days of dietary K restriction and were compared with rats without aldosterone replacement. High and normal aldosterone replacement reduced the fall in urinary K excretion and led to significantly lower plasma [K], skeletal muscle tissue K content, renal tissue K content, and greater negative cumulative balance of K compared with low aldosterone replacement. Likewise, plasma [K] and skeletal muscle tissue K content were significantly less in intact rats after 3 days of K deprivation and chronic treatment with aldosterone. Acute aldosterone treatment significantly increased urinary K excretion by isolated perfused kidneys. We conclude that incipient, developing, and established renal K conservation is not independent of mineralocorticoid activity and that the rapid fall in PAC during K depletion is necessary for maximal renal K conservation.
血浆醛固酮浓度（PAC）降低在肾脏保钾中的重要性尚不清楚。因此，我们研究了醛固酮对初期、进展期和已确立的肾脏保钾的影响。在4天的饮食钾限制期间，对肾上腺切除（ADX）并用 dexamethasone替代的大鼠持续给予高、正常或低剂量的醛固酮，并与未用醛固酮替代的大鼠进行比较。与低剂量醛固酮替代相比，高剂量和正常剂量的醛固酮替代减少了尿钾排泄的下降，并导致血浆[K]、骨骼肌组织钾含量、肾组织钾含量显著降低，钾的负累积平衡更大。同样，在缺钾3天并接受醛固酮慢性治疗后，完整大鼠的血浆[K]和骨骼肌组织钾含量显著降低。急性醛固酮治疗显著增加了离体灌注肾脏的尿钾排泄。我们得出结论，初期、进展期和已确立的肾脏保钾并非独立于盐皮质激素活性，并且钾耗竭期间PAC的快速下降对于最大程度的肾脏保钾是必要的。
