Figure 1.

Erythrocyte antioxidant enzymes in multiple sclerosis. The figure shows (a) three of the erythrocyte antioxidant enzymes – superoxide dismutase (SOD), glutathione peroxidase (GPx) and catalase – and the reaction they catalyse to combat the effects of oxidative stress. Activities of erythrocyte SOD, GPx and catalase are altered in clinically isolated syndrome, relapsing–remitting MS, and secondary progressive MS compared to healthy controls. Nitric oxide synthase (NOS) catalyses the synthesis of nitric oxide, which may contribute to oxidative stress following the reaction with superoxide resulting in peroxynitrite. (b) Adrenocorticotropic hormone (ACTH) and (c) melatonin enhance and suppress various erythrocyte enzymes.