(A) Protein extracts from the hearts of DR and DS rats at the age of 18 weeks were subjected to Western blotting with anti-p300 antibody, anti-GATA4 antibody, or anti-GAPDH antibody. (B) These extracts were then immunoprecipitated with goat anti-GATA4 polyclonal antibody and subjected to sequential Western blotting with anti–acetylated lysine antibody, anti-p300 antibody, and anti-GATA4 antibody. (C and D) Protein extracts from the hearts of DS rats treated with curcumin (50 mg/kg/d) or vehicle (1% gum arabic) for 7 weeks were subjected to Western blotting for p300, GATA4, and GAPDH (C) and then immunoprecipitated with anti-GATA4 antibody followed by sequential Western blotting for acetylated lysine, GATA4, and p300 (D). (E) The levels of signals for acetylated GATA4 and those for total GATA4 were quantified. Results are expressed as mean ± SEM from 8 vehicle-treated rats and 6 curcumin-treated rats.