ACTB and type 2 diabetes mellitus: In comparison with control rats, cardiac ATP content was remarkably reduced (Fig. 3a, P < 0.01), and the content of mtDNA, mirrored by the copy number ratio of COX I to β-actin, was extremely suppressed (Fig. 3b, P < 0.01) in the myocardium of diabetic rats, indicating the suppressions of myocardial mitochondrial function and biogenesis in T2DM rats.