Figure 2.

γENaC processing in late DCT and CNT. A. Photomicrograph showing an isolated nephron fragment with both a proximal portion of a CNT and a distal portion of the upstream DCT. The black line indicates the location of a cut to separate the two nephron segments. B. Western blot of samples from WT mice on control diet containing 25–40 tubules identified as either DCT2 (late DCT) or CNT, together with a sample (40 μg) of total kidney cortex. The blot was cut at ~100 kDa (dashed line) and stained with antibodies against NCC (upper section) or γENaC (lower section). Lanes containing kidney cortex and DCT2 expressed NCC and γENaC. Lanes containing CNT expressed γENaC but no appreciable NCC. All mice were male. C. Western blot of late DCT and CNT fragments from mice on control-Na or low-Na diets. 25–40 tubules were loaded onto individual lanes and stained for γENaC. D. Ratio of band densities of cleaved/full length γENaC. Data were obtained from WT (black symbols), heterozygotes (red symbols) and Liddle mice (blue symbols). Data represent means ± SEM for n = 6 animals on each diet, pooling results from the 3 genotypes.