PPARα-mediated transcriptional control of MCPT.Luc.781 is blocked in the hypertrophied cardiac myocyte. (a) Shown is the homologous promoter–reporter plasmid, MCPT.Luc.781, containing the PPARα response element, FARE-1, located upstream of two untranslated exons, 1A and 1B (9, 26) (top). Either MCPT.Luc.781 or a construct containing FARE-1 mutated at the position underlined in the FARE-1 DNA sequence (MCPT.Luc.781.m1) was transfected into rat neonatal cardiac myocytes in serum-free media, followed by a 60-hour exposure to either vehicle (water) control or PE. Exposure to oleate (50 μM or 250 μM) or vehicle (0) began 12 hours after transfection and was continued for 48 hours. Bars represent mean (± SEM) luciferase activity (in relative luciferase units, or RLU) in cardiac myocytes exposed to the indicated concentrations of oleate, and incubated in the absence (C) or presence of PE. Values shown were corrected for transfection efficiency using the activity of cotransfected pSV40–β-Gal plasmid and normalized (= 1.0) to the values obtained with cells exposed to vehicle alone. ^ASignificantly different from control cardiac myocytes. (b) Activity of the heterologous promoter–luciferase gene reporter plasmid (FARE1)₂TKLuc (left) or (ACO)₃TKLuc (right) in the presence of pCDM.PPAR. The values shown are RLU corrected for the activity of cotransfected pSV40–β-Gal and are normalized (= 1.0) to the activity of the reporter construct in identically treated cells cotransfected with vector backbone [pCDM(-)] and exposed to vehicle. The data shown represent the mean (± SEM) of three independent experiments. ^ASignificantly different (P < 0.05) from the control value. ^BSignificantly different from value obtained in the presence of oleate or ETYA without PE added.