EFFECT OF CELL SODIUM ON NA+/K+-ATPASE-DEPENDENT SODIUM-EFFLUX IN CORTICAL COLLECTING TUBULE OF RABBITS UNDER DIFFERENT ALDOSTERONE STATUS

Aldosterone increased the tubular volume in cortical collecting tubules (CCD) of rabbit kidney. It modulated the rate of cell sodium accumulation, under condition of ATPase inhibition (4° C, in the absence of K+). In contrast, the relationship between Na+/K+-ATPase-dependent Na+ extrusion rate and intracellular Na+ concentration (Na+i) was similar in control, adrenalectomized, and aldosterone-treated adrenalectomized animals; Na+ extrusion rate increased with Na+i, up to 70 mM Na+i, and then plateaued. This indicates that aldosterone does not modify the characteristics of Na+i-dependent Na+ extrusion rate by the Na+/K+-ATPase pump in CCD. © 1990.