EFFECTS OF ARGININE GLUTAMATE AND ASPARTATE ON AMMONIA UTILIZATION IN PERFUSED BOVINE LIVER

Rates of removal of ammonia from the perfusate of isolated bovine liver preparations were measured following injected loads of ammonium acetate. The effects, upon these rates, of infusing arginine, aspartate, and glutamate, separately and in pairs, were compared statistically. Such a hitherto unpublished treatment of data made it possible to compare quantitatively for the first time metabolic pathways of ammonia removal in the liver alone. Ammonia removal was greatly accelerated by arginine, arginine plus aspartate, and arginine plus glutamate, only slightly by aspartate, and not at all by glutamate. Changes in plasma concentrations of urea and basic amino acids were also observed. These data supported the conclusion that hepatic removal of excess ammonia occurs primarily through the Krebs-Henseleit ornithine-urea cycle pathway. Glutamate acceleration of ammonia removal, reported to occur in intact animals, must take place elsewhere than in the liver. © 1968.