A, Currents from Xenopus oocytes expressing ENaC subunits shown were assessed by two-electrode voltage clamp at −100 mV. Recordings were performed in a buffer containing 110 mM Li+, and supplemented with 1 mM t-CA or 100 μM amiloride, as indicated. Currents at baseline and in the presence of t-CA or amiloride were measured at the end of each treatment period. B, Amiloride-sensitive currents (blue) in the absence (−) or presence (+) of t-CA were transformed as log(−current) and plotted. Absolute currents (red) were similarly plotted for uninjected oocytes. Summary statistics are mean (SD). Transformed amiloride-sensitive currents were analyzed by repeated measures two-way ANOVA, with Sidak’s multiple comparison test to examine the effect of t-CA. Transformed absolute currents from uninjected oocytes were analyzed by paired Student’s t test. The number of oocytes measured for each group is shown in parentheses.