van Buren M, Rabelink A J, Bijlsma J A, Koomans H A
Department of Nephrology and Hypertension, University Hospital Utrecht, The Netherlands.
Nephrol Dial Transplant. 1993;8(6):495-500. doi: 10.1093/ndt/8.6.495.
Potassium (K) loading is followed by a rapid increase in sodium (Na) and K excretion. To evaluate the influence of Na intake on this effect, we studied the acute natriuretic and kaliuretic response to a single oral K load (100 mmol) in six healthy volunteers equilibrated on a 10-, 100-, and 400-mmol Na intake. Compared to the 100-mmol Na intake, the 400-mmol Na intake greatly enhanced the natriuretic effect of the K load; during the 10-mmol Na intake no natriuresis but even some Na retention occurred. The kaliuretic effect was not significantly changed and occurred at similar values of plasma K. Plasma aldosterone was suppressed during the 400-mmol Na diet and stimulated during the 10-mmol Na diet, but the relative increments after the KCl load did not differ among the three diets. In conclusion, whereas the effect of a K load on kaliuresis is relatively independent of Na intake, its effect on Na excretion varies from marked natriuresis to slight Na retention. The Na retention is probably due to acute K-induced aldosterone stimulation, and the natriuresis to K-induced increase in distal Na delivery not utilized to promote K excretion. Apparently, the integration of renal Na and K handling after a K load is such that K balance is maintained at the cost of Na balance.
钾（K）负荷后，钠（Na）和钾的排泄会迅速增加。为了评估钠摄入量对这种效应的影响，我们研究了六名健康志愿者在摄入10、100和400毫摩尔钠的平衡状态下，对单次口服钾负荷（100毫摩尔）的急性利钠和利尿反应。与摄入100毫摩尔钠相比，摄入400毫摩尔钠极大地增强了钾负荷的利钠效应；在摄入10毫摩尔钠期间，没有出现利钠现象，甚至还出现了一些钠潴留。利尿效应没有显著变化，且在相似的血钾水平时出现。在摄入400毫摩尔钠的饮食期间，血浆醛固酮受到抑制，而在摄入10毫摩尔钠的饮食期间则受到刺激，但在氯化钾负荷后，三种饮食之间的相对增量没有差异。总之，钾负荷对利尿的影响相对独立于钠的摄入量，但其对钠排泄的影响则从明显的利钠到轻微的钠潴留不等。钠潴留可能是由于急性钾诱导的醛固酮刺激，而利钠则是由于钾诱导的远端钠输送增加，而这部分钠并未用于促进钾的排泄。显然，钾负荷后肾脏对钠和钾的处理整合情况是，以钠平衡为代价来维持钾平衡。
