Figure 3

Angiotensin II increases NHE3 gene transcription. (A) Monolayers were treated with AII (1 nM, basolaterally) for varying times and RNA harvested and analyzed for NHE3 mRNA by real-time PCR. GAPDH was used as a constitutive mRNA control and NHE3 mRNA increases calculated by the ΔΔCt method (33). Values are means ± SEM for four separate experiments. * P < 0.05 + P < 0.01 ++ P < 0.001 compared with zero time untreated control by analysis of variance using a Bonferroni correction. (B) Monolayers were transfected with plasmids containing a 2200 bp segment of the rat NHE3 gene promoter linked to firefly luciferase cDNA and another with the thymidine kinase promoter linked to Renilla luciferase as a constitutive control. Cells were treated with AII (0–1 μM) 24 hours after transfection and monolayers were harvested and luciferase activities measured after 24 hours. Values are means ± SEM for four separate experiments. * p < 0.05 compared with untreated zero time control by analysis of variance using a Bonferroni correction.