Effect of Hypokalemia on the Reductive Amination of α-Ketoglutarate by Mitochondria from Normal and Cirrhotic Rat Liver

Abstract

The reductive amination of α-ketoglutarate by glutamic dehydrogenase with malate as the hydrogen donor has been studied under anaerobic conditions, with added adenosine triphosphate, in normal and cirrhotic rat liver mitochondria isolated from normokalemic and hypokalemic animals. The formation of glutamate and aspartate, the products of the reductive amination of α-ketoglutarate, was measured as an index of the amount of ammonia incorporated. There was no difference in the amount of ammonia incorporated by normal and cirrhotic rat liver mitochondria. Hypokalemia lowered the ability of liver mitochondria to incorporate ammonia by the reductive amination of α-ketoglutarate in normal animals, and more strikingly in cirrhotic animals, although the concentration of potassium in the ,.mitochondria was unchanged. Incubation of mitochondria from hypokalemic animals with potassium partially restored the ability to incorporate ammonia, but without a significant change in the total mitochondrial potassium concentration.