Aizman R I, Rabinowitz L, Mayer-Harnisch C
Department of Human Physiology, University of California, Davis 95616, USA.
Am J Physiol. 1996 Feb;270(2 Pt 2):R434-42. doi: 10.1152/ajpregu.1996.270.2.R434.
Mechanisms underlying the change in K excretion (UKV) during the first 6 days after uninephrectomy (UNX) were examined in unanesthetized rats. Arterial plasma K concentrations (PK) were 0.55 meq/l above control values at 12 and 24 h after UNX but were not significantly different 36-72 h after UNX. To determine if there was an increased sensitivity of the distal K secretory mechanism to increases in PK, an intragastric KCl infusion was given. The delta UKV/delta PK per kidney values were in the following order: 6-day UNX > 2-day UNX > control. In the normal rats, an acute increase of 0.5 meq/l in PK increased UKV by an amount approximating 25% of the increase in UKV observed 12-24 h after UNX. Amiloride, administered 48 h after UNX, increased Na excretion per kidney and decreased UKV per kidney approximately twice as much in UNX as in control groups. Thus an adaptive increase of amiloride-inhibitable K secretion occurred within 2 days of UNX and continued to increase thereafter. This K adaptation may have been induced by transient increases in PK.
在未麻醉的大鼠中研究了单侧肾切除（UNX）后最初6天内钾排泄量变化（UKV）的潜在机制。UNX后12小时和24小时，动脉血浆钾浓度（PK）比对照值高0.55毫当量/升，但UNX后36 - 72小时无显著差异。为了确定远端钾分泌机制对PK升高是否存在敏感性增加，进行了胃内氯化钾输注。每侧肾脏的UKV变化量/ PK变化量值顺序如下：UNX 6天组 > UNX 2天组 > 对照组。在正常大鼠中，PK急性升高0.5毫当量/升会使UKV增加的量约为UNX后12 - 24小时观察到的UKV增加量的25%。在UNX后48小时给予氨氯吡咪，每侧肾脏的钠排泄量增加，每侧肾脏的UKV减少，在UNX组中减少的幅度约为对照组的两倍。因此，在UNX后2天内发生了氨氯吡咪可抑制的钾分泌适应性增加，此后持续增加。这种钾适应性可能是由PK的短暂升高诱导的。
