Aldosterone stimulates K secretion across mammalian colon independent of Na absorption.
Aldosterone stimulates K secretion across mammalian colon independent of Na absorption.
复制标题
醛固酮刺激哺乳动物结肠中钾的分泌，与钠的吸收无关。
DOI：
10.1073/pnas.86.1.397
复制
发表时间：
1989
影响因子：
11.1
通讯作者：
Halm,DR
中科院分区：
文献类型：
--
作者：
Rechkemmer,G;Halm,DR
用同位素测定的单向通量在体外测定了豚鼠（Cavia porcellus）远端结肠的钾转运。通过阿米洛利敏感性短路电流（Isc）测量，醛固酮刺激产电性钠吸收，并将净钾吸收从每小时+2.5 +/- 0.2 microEq/cm 2降至每小时+0.8 +/- 0.3 microEq/cm 2（平均值+/- SEM）。阿米洛利除了粘膜溶液中没有增加净钾吸收，如预期的，如果抑制活性钠吸收将减少活性钾分泌在远端肾单位。阿米洛利不敏感的Isc为-1.0 +/- 0.2 microEq/cm 2/hr（平均值+/- SEM），并且通过粘膜添加Ba（一种K通道阻滞剂）抑制。此外，布美他尼的serlavine解决方案也抑制了这种负Isc，和K转运恢复到控制水平的净吸收。因此，阿米洛利不敏感的负Isc与醛固酮刺激的活性K分泌一致。醛固酮对活性钾分泌途径的刺激在不改变活性钾吸收途径的情况下发生。这些结果表明，醛固酮刺激的钾分泌途径独立于阿米洛利敏感的钠吸收途径，这也是由醛固酮刺激。
K transport across guinea pig (Cavia porcellus) distal colon was measured in vitro using isotopically determined unidirectional fluxes. Aldosterone stimulated electrogenic Na absorption, as measured by amiloride-sensitive short-circuit current (Isc), and reduced net K absorption from +2.5 +/- 0.2 microEq/cm2 per hr to +0.8 +/- 0.3 microEq/cm2 per hr (mean +/- SEM). Amiloride addition to the mucosal solution did not enhance net K absorption, as expected if inhibiting active Na absorption would reduce active K secretion as in the distal nephron. The amiloride-insensitive Isc was -1.0 +/- 0.2 microEq/cm2 per hr (mean +/- SEM) and was inhibited by mucosal addition of Ba, a K channel blocker. Addition of bumetanide to the serosal solution also inhibited this negative Isc, and K transport returned to the control level of net absorption. Thus, the amiloride-insensitive, negative Isc is consistent with active K secretion stimulated by aldosterone. This stimulation of an active K secretory pathway by aldosterone occurred without altering the active K absorption pathway that also is present. These results indicate that the aldosterone-stimulated K secretory pathway operates independently of the amiloride-sensitive Na absorption pathway, which also is stimulated by aldosterone.