Figure 4.

Stability of ENaC mRNAs in mCCD cells treated with aldosterone and dDAVP. Cells were cultivated for 24 h in the presence of 0.1% ethanol (control), 300 nM aldosterone or 10 nM dDAVP, then transcription was stopped by addition of actinomycin D (10 µM final concentration) and cells were further cultivated for the times indicated. Total RNA was prepared at each time point and relative levels of α-, β- and γ-ENaC mRNA were quantified by RT–PCR including β-actin mRNA as an independent control mRNA. Values were normalized to 18S/28S rRNA. −RT controls showed no signals (data not shown). mRNA levels at time point 0 h of each condition (control, aldosterone, dDAVP) was referred to as 100% mRNA remaining for each transcript. Relative mRNA values of later time points were calculated referring to the corresponding (same culture condition) mRNA value at time point 0 h. Data represent mean ± SD (n = 3).