Effect of Intravenously Administered Amino Acids on Blood Ammonia. ∗

Summary

1. Glycine, alanine or an acid hydrolysate of casein were intravenously infused in dogs over a 2-hour period, and the concentrations of ammonia, urea and amino acid nitrogen in the blood were determined at 30-minute intervals. 2. At rates of infusion of glycine above 1 mg amino N, kg min. significant increases in blood ammonia occurred, which were directly related to amounts of glycine infused. At the maximum infusion rate used (7 mg amino N kg/min.) the dog expired in respiratory failure at the end of the 2-hour infusion. The results of these experiments indicate that the toxicity attributed to rapid rates of infusion of glycine may actually be due to ammonia intoxication. 3. After administration of a casein hydrolysate increases in blood ammonia were less and those of urea were greater than predicted from administration of glycine at comparable rates. This suggests that certain amino acids in the mixture decrease blood ammonia levels by enhancing urea production.