Figure 7. Effect of eplerenone on Na⁺ excretion and I_Na .

A, single dose of eplerenone (30 mg kg^–1 p.o.) or vehicle was administered to rats on a low‐Na diet for 1, 3 or 7 days. Na⁺ excretion was measured from 0 to 2 h and from 2 to 4 h after the gavage. Data represent the mean ± SEM for four rats at each time point. *Statistical difference of the indicated low‐Na group relative to controls (0.01 < P < 0.03). B, I _Na measured in CCDs isolated 4 h after administration of eplerenone or vehicle in CCDs isolated from rats on a low‐Na diet for 3 or 7 days. Data represent the mean ± SEM for 11–28 measurements on three to five animals for each condition.