The downregulation of the TCA cycle proteins has been observed in mitochondria of isolated mTAL of SS rats.91 Several studies from our laboratory have shown that reduction of medullary blood flow in the SD rat with chronic medullary infusion of H2O2 or an SOD inhibitor (DETC) result in a salt-sensitive form of hypertension.93,94 So too, reduction of renal medullary oxidative stress in SS rats by intrarenal infusion of L-arginine reduces salt induced hypertension in SS rats.95 The lack of significant changes in metabolism-related genes in OM may reflect salt insensitivity in SD. This evidence concerns the gene SOD1 and hypertensive disorder.