The Metabolism of Amino Acids in Diabetes Mellitus.

The amino acid content of fasting human blood appears to be quite constant. Extensive surveys (1) have revealed only a few diseases in which the blood amino acid level is modified significantly. Acute yellow atrophy of the liver is associated with a rise in amino acids in the blood, whereas hypoaminoacidemia has been reported in patients with nephrosis and in pneumococcal pneumonia (2). Concerning the fasting amino acid level in diabetes mellitus there is little agreement. Several investigators (la, 3) have observed elevated amino acid levels in a few of their diabetic subjects. Greene, Sandiford and Ross (lb) studied 116 diabetics and observed that the average amino acid level was within normal limits. No accurate data on the condition or treatment of these patients were given. On the other hand, a high blood amino acid content has been reported in dogs with experimentally induced diabetes (4). Luck, Morrison and Wilbur (5) observed that insulin lowered the amino acid content of blood in both experimental animals and normal human subjects. These results have been confirmed by several investigators (6) using the Folin colorimetric method and by Farr and Alpert (7) using Van Slyke and MacFadyen's manometric ninhydrin method (8). Luck also studied two diabetic patients under insulin treatment and observed low normal fasting amino acid levels. The lack of agreement of existing data on the blood amino acid content in human diabetes mellitus, together with the paucity of data on the clinical condition and therapy of the patients, suggested the present study.