Cardiac Oxidative Stress Is Elevated at the Onset of Dilated Cardiomyopathy in Streptozotocin-Diabetic Rats

pathway,7,8 formation of advanced glycation end products,7 and increased production of reactive oxygen species (ROS). The latter factor may decrease nitric oxide (NO) bioavailability and promote the appearance of endothelial dysfunction,9 which will increase total peripheral resistance and heart work and eventually worsen heart performance. Nitric oxide, which is synthesized by nitric oxide synthase (NOS) from L-arginine, is one of the most important regulators of myocardial function.10,11 In the heart, constitutive NOS (eNOS) and inducible NOS (iNOS), both of which are present in cardiac myocytes and vascular endothelium, are the principal isoenzymes that produce NO.12,13 Under physiological conditions, NO produced by eNOS increases diastolic relax