FREE AMINO ACIDS IN BLOOD. VI 447 
CONCLUSIONS 
After the ingestion of glutamine, the plasma level is elevated and an increase in the 
levels of glutamic acid and an uncharacterized compound migrating just to the left 
of glutamic acid on chromatograms is observed. The levels of all three compounds 
rise and fall together. The uncharacterized compound is probably a metabolite of 
glutamine. It is detectable at times in normal plasma and more frequently in plasma 
samples from patients with leukemia. No marked increase in urinary excretion of 
glutamine, other free amino acids, urea, or uric acid was observed after ingestion of 
50 g of glutamine. 
Leukocytes and blood platelets concentrate glutamine from plasma while ery- 
throcytes do not. Erythrocytes are not normally freely permeable to glutamine. In 
some of the studies, the level of glutamine in erythrocytes was essentially unchanged 
when plasma glutamine was elevated. In other cases erythrocyte glutamine increased 
slightly. When the conditions in the blood are altered by infusion of saline, glutamine 
may enter red cells more rapidly and equilibrate completely with plasma. 
The response of the leukemic patients was variable. The one patient with chronic 
lymphatic leukemia that was studied appeared to handle glutamine in a normal 
manner. One of the patients (H. Gol.) with chronic granulocytic leukemia had a 
very abnormal response and it appeared that glutamine was metabolized more 
rapidly in this patient. Two ingestion studies with the same patient after drug 
therapy indicated a nearly normal response to the ingestion of glutamine after re- 
duction of the white cell mass. One patient (R. Tap.) with chronic granulocytic 
leukemia also showed an abnormal response to a glutamine load, but another patient 
responded in a manner not clearly distinguishable from normal. These findings 
indicate that glutamine metabolism is not significantly affected in all patients and 
further suggests that in the more extreme cases of untreated granulocytic leukemia 
glutamine metabolism may be distinctly abnormal. The conclusions from the gluta- 
mine ingestion studies agree with the overall impression gained from the study of 
blood free amino acids. Deviations from the normal levels are not observed at all 
times in the same patient, although on occasion the levels may be very abnormal. 
The results of our studies of normal individuals are in agreement with previous 
studies. BESSMAN ef al.4! observed increases in the levels of glutamine and glutamic 
acid in plasma from cats after intra-intestinal administration of glutamine. MEISTER 
et al.” observed similar increases in glutamine and glutamate levels in phenylketonuric 
subjects after oral intake of glutamine. Previous investigatiors did not study the 
effects of glutamine ingestion on the free amino acid levels of erythrocytes, leukocytes, 
or blood platelets. 
ACKNOWLEDGEMENTS 
Mr. RICHARD Ray assisted in the preparation of the photographic illustrations. The 
experimental work was supported by Grant C-3134 from the U.S. Public Health 
Service. 
REFERENCES 
'G. Rouser, Studies on the Biochemistry of White Blood Cells, Ph. D. thesis, The University of 
Rochester, New York, 1952, 158 pp. 
2G. Rouser, in J. W. Resuckx, F. H. BETHELL AND R. W. Monro, (Eds.), The Leukemias: 
Etiology, Pathophysiology, and Treatment, Academic Press, New York, 1957, p. 361. 
