Experimental mice with high-fat diet-/streptozotocin-induced diabetes mellitus reveal a decrease in the expression of the Ppargc1a and Mfn2 and Opa1 genes as well as an increase in the expression of the Drp1. This suggests that the induction of diabetes mellitus is accompanied by a remodeling of the mitochondrial network of myocytes, namely a decrease in mitochondrial biogenesis and mitochondrial fusion as well as an increase in mitochondrial fission episodes. Here, OPA1 is linked to diabetes mellitus.