The Effect of Feeding Excess Glycine,L-Arginine,and DL-Methionine to Rats on a Casein Diet. *

Summary

In these experiments on rats, the addition of 4.8% glycine, 4.8% DL-methionine or 4.8% glycine plus 4.8% DL-methionine to a 12% casein diet did not alter the nitrogen balance as compared to controls receiving 12% casein alone but did reduce the nitrogen balance index, the excess amino nitrogen not contributing to the retention of nitrogen in the animal. The data indicates, on the other hand, that excess arginine (1.7%) contributes in part, to the retention of nitrogen. The addition of 4.8% glycine or 4.8% glycine plus 1.7% L-arginine to a casein diet containing excess methionine counteracted the weight loss and in part the kidney hypertrophy caused by the excess methionine. The slight increases in thyroid weights, associated with excess methionine, were also antagonized by glycine and arginine. Under the conditions of these experiments urinary creatinine and creatine excretion was not increased in rats by feeding excess glycine. The significance of these results is discussed.