Representative WB analyses of β1-adrenoreceptor (A) and semiquantitative RT-PCR analyses of α-MHC and β-MHC (B) expressions in left ventricular tissue RNA extracts from non-diabetic (ND) and diabetic rats (DM), treated or not with OB. Quantitative analyses are reported in the histograms, which represent the ratio of net intensity of bands with GAPDH. Data are expressed as percentage variations from the ND-CTRL value. Data are means ± SD of 8–10 rats per group. Statistical significance: * P < 0.05 vs ND-CTRL; ** P < 0.01 vs ND-CTRL; † P < 0.05 DM-CTRL.