Knockdown of AC6 through RNA interference attenuates the maximal stimulation of renin gene expression induced by the combination of PACAP and rosiglitazone. Calu-6 cells were transfected with nontargeting siRNA as control (siControl) or with siAC6. A, Efficacy of the knockdown: AC6 and β-actin (internal control) immunoblot. B, Efficacy of the knockdown: AC6 mRNA expression. AC6 and β-actin (internal control) mRNA levels were quantified by real-time PCR. C, Specificity of the knockdown: AC1, AC3, and AC7 mRNA expression; ACs and β-actin (internal control) mRNA levels were quantified by real-time PCR. D, Specificity of the knockdown: preserved inducibility the classical PPARγ-regulated gene FABP-4. FABP-4 and β-actin (internal control) mRNA levels were quantified by real-time PCR. E, Effect of AC6 deficiency on renin mRNA levels. Renin and β-actin (internal control) mRNA levels were quantified by real-time PCR. Rosiglitazone was applied at 500 nm and PACAP at 300 nm. Calu-6 cells were incubated for 16 h as indicated. Rosi, Rosiglitazone. The data shown are means ± sem; *, P < 0.05 relative to siControl-Control; **, P < 0.05 relative to siAC6-Control; #, P < 0.05 relative to siControl-PACAP; §, P < 0.05 relative to siControl-PACAP + Rosi.