Hormonal regulation of rat renal proximal tubule brush-border membrane ionic permeability.
Hormonal regulation of rat renal proximal tubule brush-border membrane ionic permeability.
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大鼠肾近曲小管刷状缘膜离子渗透性的激素调节。
DOI：
10.1152/ajprenal.1992.263.1.f144
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发表时间：
1992
期刊：
影响因子：
--
通讯作者：
Abramson,RG
中科院分区：
文献类型：
--
作者：
Lipkowitz,MS;London,RD;Beck,JC;Abramson,RG
The effects on ionic permeability of toxins and hormones that activate or deactivate the guanine nucleotide regulatory (G) proteins that govern adenylate cyclase activity were examined in rat renal proximal tubule cell brush-border membranes. These studies demonstrate that activation of stimulatory G (Gs) proteins by cholera toxin or parathyroid hormone and deactivation of inhibitory (G (Gi) proteins by pertussis toxin result in a selective increase in Cl- permeability relative to that of K+ as determined with the potential-sensitive fluorescent probe 3,3'-dipropylthiadicarbocyanine iodide [diS-C3-(5)]. In contrast, activation of Gi by angiotensin II significantly decreases relative Cl- permeability. The selective increase in relative Cl- permeability induced by parathyroid hormone results in an inside-negative potential in membrane vesicles exposed to an inward NaCl gradient that is of sufficient magnitude to stimulate electrogenic, Na(+)-dependent glucose transport. These data suggest that the relative ionic permeabilities of brush-border membranes are tonically regulated by the opposing effects of hormones that act via Gs or Gi proteins. Changes in membrane potential resulting from this regulation may play an important role in modifying transport in the proximal tubule.
