SOD1 and hyperhomocysteinemia: Using mice with a targeted deletion of the murine Sod1 gene, we examined the effects of deficiency of superoxide dismutase 1 (SOD1; the most abundant cellular isoform of superoxide dismutase in vascular tissues [20]) on vasomotor function and vascular structure in cerebral blood vessels of mice with diet-induced hyperhomocysteinemia.