Fig. 6.

Regulation of ENaC subunits by dexamethasone in the presence of aldosterone. Rats were infused with aldosterone (12 μg/day) with or without dexamethasone (60 μg/day) for 7 days. A: gels for Western blots were loaded with 40 μg protein/lane. Different lanes represent different animals. Blots were probed with anti-αENaC, anti-βENaC, or anti-γENaC antiserum. For the anti-αENaC blots, different portions of the same gel were processed differently to visualize the staining of the full-length (90 kDa) and cleaved (20–30 kDa) forms of the subunit. B: quantitation of effects of dexamethasone on expression of Na⁺ channel protein in the presence of aldosterone. Densitometric data were normalized to means of measurements with aldosterone alone and represent means ± SE; n = 4 animals for each condition. Stars indicate statistically significant difference from controls (P < 0.05). C: quantification of effects of aldosterone, dexamethasone, and aldosterone+dexamethasone on the expression of αENaC protein. Densitometric data were normalized to means of control measurements and represent means ± SE; n = 4 animals for each condition. Stars indicate statistically significant difference. Values for aldosterone and dexamethasone are significantly different from controls (P < 0.001). Values for aldosterone+dexamethasone are significantly different from aldosterone alone (P = 0.003).