Schuster V L
J Clin Invest. 1986 Dec;78(6):1621-30. doi: 10.1172/JCI112755.
Cyclic AMP stimulates HCO3 secretion and Cl self-exchange in rabbit cortical collecting tubule. We found that varying peritubular [Cl] changed the Cl self-exchange rate with saturation kinetics (Km, 3-4 mM). HCO3 secretion also showed saturation kinetics as a function of mean luminal [Cl] (Km, 4-11 mM). Both Cl self-exchange and Cl-HCO3 exchange thus appear to be carrier-mediated. Addition/removal of basolateral HCO3 qualitatively changed Cl and HCO3 transport as expected for Cl-HCO3 exchange, but quantitatively changed Cl absorption more than HCO3 secretion. The diffusive Cl permeability and the transepithelial conductance in the presence of HCO3/CO2 and cAMP were higher than in their absence suggesting that HCO3/CO2 and cAMP together increase a conductive Cl pathway parallel to a 1:1 Cl-HCO3 exchanger. Thus, cAMP not only stimulates the overall process of anion exchange (probably by increasing an electroneutral exchanger and/or a series Cl conductance), but also stimulates a Cl conductance parallel to the exchange process.
环磷酸腺苷（cAMP）刺激兔皮质集合管中的HCO₃分泌和Cl⁻自我交换。我们发现，改变肾小管周围[Cl⁻]会以饱和动力学（Km，3 - 4 mM）改变Cl⁻自我交换速率。HCO₃分泌作为平均管腔[Cl⁻]的函数也呈现饱和动力学（Km，4 - 11 mM）。因此，Cl⁻自我交换和Cl⁻-HCO₃交换似乎都是载体介导的。如Cl⁻-HCO₃交换所预期的那样，基底外侧HCO₃的添加/去除定性地改变了Cl⁻和HCO₃的转运，但定量地改变Cl⁻吸收比HCO₃分泌更多。在存在HCO₃/CO₂和cAMP的情况下，扩散性Cl⁻通透性和跨上皮电导高于不存在时，这表明HCO₃/CO₂和cAMP共同增加了一条与1:1 Cl⁻-HCO₃交换体平行的传导性Cl⁻途径。因此，cAMP不仅刺激阴离子交换的整体过程（可能是通过增加电中性交换体和/或一系列Cl⁻电导），而且还刺激与交换过程平行的Cl⁻电导。
