PDE5A and chronic kidney disease: Indeed, analysis of left ventricular myocardial samples showed that overall PDE activity (6.7 ± 0.5 vs. 5.7 ± 0.4 AU μg protein−1, P = 0.18) and specifically PDE5 activity (1.58 ± 0.39 vs. 0.78 ± 0.46 AU μg protein−1, P = 0.20) as well as PDE5 mRNA expression (0.029 ± 0.002 vs. 0.027 ± 0.004 AU, P = 0.78), were not different between the Normal and DM + HFD + CKD swine, respectively.