Increased expression of PPARα target genes in hearts of transgenic mouse lines (MHC-PPAR mice) that express PPARα in a cardiac-restricted manner. (a) Representative autoradiographs of Northern (top) and Western (middle) blot studies performed with heart samples from 6-week-old mice from four independent MHC-PPAR lines. At the exposure shown, endogenous PPARα could not be detected in NTG samples. FLAG-PPARα protein was detected in the transgenic mice using an antibody directed against either PPARα (shown here) or FLAG (data not shown). Cardiac-specific expression of FLAG-PPARα mRNA was confirmed by Northern blot analysis performed with multiple tissues (bottom panel represents the 402-2 line). H, heart; BAT, brown adipose tissue; SM, skeletal muscle; K, kidney; L, liver. (b) The expression of PPARα target genes is increased and inducible by PPARα activator in the hearts of MHC-PPAR mice. The graphs represent the results of Northern blot analyses performed with the probes indicated using RNA isolated from ventricle of male and female NTG or MHC-PPAR littermate mice fed control chow or a 7-day course of chow containing Wy-14,643 (0.1% wt/wt). Bars represent mean mRNA levels (arbitrary units, AU) quantified as described in Methods (n ≥ 7 mice for each group). The inset shows representative autoradiographs of Western blot analyses. *P < 0.05 versus NTG littermate mice. **P < 0.05 versus MHC-PPAR mice fed control chow and NTG mice. Far right: Bars represent mean malonyl-CoA−inhibited CPT enzyme activity (n = 3 for each group). ^†P < 0.05 versus NTG littermate mice.