Effect of streptozotocin diabetes on some urea cycle enzymes

Streptozotocin induced diabetes in rats increased the activities of the three mitochondrial enzymes, carbamylphosphate synthetase, ornithine transcarbamylase and N-acetylglutamate synthetase, but not of the cytosolic N-acetylglutamate deacylase. Levels of both N-acetylglutamate and arginine, which are activators of carbamylphosphate synthetase and N-acetylglutamate synthetase respectively, increased in diabetes. These results serve to explain the increase both of mitochondrial citrulline and urea formation in hepatocytes and the increased urea excretion in diabetes.