Formation of glutamine and activities of glutamine synthetase in goats.

When goats were administered orally with urea in a dose of 0.3 g per kg of body weight, the blood concentration of glutamine-N in the jugular vein increased to about 6μg per ml of plasma, reflecting the removal of ammonia by forming glutamine in the animal body. The blood glutamine seemed to undergo a more rapid turnover than the blood urea. Glutamine synthetase catalizes the formation of glutamine from ammonia and glutamic acid. It was made clear that the activity of the enzyme per gram of tissue was the highest in the spleen, which was followed by the retina, cerebrum, liver, cerebellum and kidney in this regard. The whole tissue activity of the enzyme, however, was higher in the liver than in the spleen. It was considered that the activity of glutamine synthetase in the spleen increased in kids with growth, and that the spleen might play an important role in forming glutamine in adult goats.