GSR and type 2 diabetes mellitus: In addition, decreased antioxidant defense is a common finding in type 2 diabetes, which may be partially attributed to the spontaneous glycosylation of key antioxidant enzymes such as catalase, superoxide dismutase, glutathione-S-transferases, glutathione peroxidase, glutathione reductase, and others, as well as depletion of the intracellular pool of NADPH·H+ [85,210].