Positive Effect of Tyrosine Feeding Upon Excretion of Reducing Urinary Compound in Myasthenia Gravis.

Abstract

In the course of the studies of the reducing urinary substance recently described by Medes, Berglund and Lohmann, 1 in a case of Myasthenia gravis, some feeding experiments with amino acids have been carried out. The subject for our experiments was the same patient with Myasthenia gravis which was studied in the publication referred to above. Tyrosine and glycine were fed. Phenyl alanine was not available. The amounts fed were 2.5 gm. and 5 gm. The patient was on a uniform diet and the total amount of reducing power of the urine was determined by the Folin and Berglund 2 method, for the so called normal urine sugar. From previous work it is known that the reducing value of the 24 hour urine in normal individuals on a diet similar to our patient is about 1 gm. of glucose. The urine of our patient, as seen from the table, shows a reducing value corresponding to from 2.5 to 3.0 gm. per 24 hours. As shown in the table, the feeding of tyrosine brings about a definite increase lasting 2 days, while the feeding of glycine shows no significant increase.

Besides the tyrosine experiment reported in the table, tyrosine has been fed to the same patient in other experiments, once in 1 gm. doses continued over 2 days and followed by a 2.5 gm. dose, and once in a 5 gm. dose. In all instances has there been an unmistakable increase in the reducing value of the urine.