Altered membrane ionic permeability in a rat model of chronic renal failure.
Altered membrane ionic permeability in a rat model of chronic renal failure.
复制标题
慢性肾衰竭大鼠模型中膜离子渗透性的改变。
DOI：
10.1038/ki.1992.290
复制
发表时间：
1992
影响因子：
19.6
通讯作者：
Abramson,RG
中科院分区：
文献类型：
--
作者：
London,RD;Lipkowitz,MS;Abramson,RG
Altered membrane ionic permeability in a rat model of chronic renal failure. Acute elevations in intracellular adenosine 3′,5′-cyclic monophosphate (cAMP) concentrations are known to increase ionic chloride permeability in diverse tissues. To determine if chronic endogenous increases in cAMP are associated with sustained alterations in membrane ionic permeabilities, renal cortical brush border membrane vesicles (BBMV) were prepared and red blood cells were harvested in a model of chronic renal failure, the 75% nephrectomized rat. Relative ionic permeabilities were determined using the potential-sensitive fluorescent probe 3,3′-dipropylthiadicarbocyanine iodide [diS-C3-(5)]. These studies demonstrate that renal cortical homogenate and RBC cAMP concentrations are increased in chronic renal failure animals. In the same animals relative ionic chloride permeability (PCl/PK) was significantly increased in renal cortical BBMV and RBC ghosts: PNa/PK was not affected. This selective change in permeability results in a significant increase in PCl/PNa and hyperpolarization of BBMV of sufficient magnitude to stimulate Na+-dependent glutamine transport. The change in glutamine uptake was not consequent to an alteration in the kinetics of glutamine transport or delayed dissipation of the inward Na+gradient. Renal hypertrophyper sedid not effect renal homogenate cAMP concentration or relative ionic permeability of renal cortical BBMV prepared from kidneys of uninephrectomized animals fed a 40% protein diet. These studies demonstrate that relative ionic chloride permeability and tissue [cAMP] are chronically increased in diverse cells (renal proximal tubule and RBCs) in a rat model of renal failure. These findings suggest that membrane ionic permeability may be altered and electrogenic transport secondarily perturbed in renal failure in association with hormonally-induced chronic elevations of intracellular cAMP concentrations.
