Distribution of an ammonia load in the normal rat

An intraportal load of ammonium chloride was administered to normal rats. Blood from the hepatic vein, liver, muscle, and brain was analyzed for its ammonia and glutamine content at various times after the load, to determine the distribution of the ammonia injected. The effect of the ligation of the renal pedicle, of the dose administered, of the size of the animal, and of the administration of a second dose on the rate of the ammonia disappearance from the blood, and the influence of the ligation of the hepatic pedicle on the distribution of the ammonia load were also investigated. It was observed that the muscle is highly efficient in removing ammonia from the circulation; the metabolite apparently is actively retained in this tissue. When the liver is excluded the capacity of the animal to handle the ammonia load is greatly impaired. Under this condition glutamine synthesis is depressed and the ability of muscle to fix ammonia is diminished.