Figure 6.

mRNA abundance of ENaC and (Na⁺+ K⁺)-ATPase in colon. (a) Analysis of the mRNA abundance of the α-, β-, and γ-subunit of the ENaC and α1- and β1-subunit of the (Na⁺+ K⁺)-ATPase in colons of 8-day-old wild-type (+/+) and MR-deficient (−/−) mice by ribonuclease protection assay. (b) Ribonuclease protection assay signal was quantified by phosphoimaging, and results are expressed as ratio of the respective subunit mRNA to TBP (TATA-box binding protein) and GAPDH (glyceraldehydephosphate dehydrogenase) mRNA, respectively, used as internal standards. n, number of measurements/number of animals used. Because single colon RNA preparations did not yield enough RNA, ribonuclease protection assays were performed with RNA from pooled colons. Therefore, no SEM bars are given in b.