334 E. ROBERTS AND D. G. SIMONSEN 
differences were found between the tissues of the control and tumor-bearing animals. 
The above observations show clearly that the tissues of rodents bearing  trans- 
plantable tumors maintain a remarkably constant pattern of easily extractable nin- 
hydrin-reactive constituents during progressive and eventually fatal growth of the 
neoplasms. Only in the terminal stages do there appear to be alterations, the most 
frequently observed change being a decrease in content of free glutamine. It is 
interesting that plasma-glutamine levels generally were lower and in some instances 
glutamic and aspartic acid and alanine concentrations were higher than normal in 
patients with acute myeloblastic and lymphoblastic and chronic lymphocytic 
leukemias and in the body fluids of patients with carcinoma of the breast, Hodgkin’s 
disease, lymphosarcoma and reticulum cell sarcoma*. In some patients treatment 
with chemotherapeutic agents tended to cause an increase in plasma glutamine 
toward normal levels. Decreases in glutamine and increases in glutamic acid content 
in plasma were also observed in tumor-bearing rats®®. 
Influence of dietary variations on free amino acids 
Effects of starvation and dehydration. A paper-chromatographic study was made of 
the effects of starvation for g days on the content of free amino acids in liver, muscle 
and blood and on urinary excretion, comparing the results with those obtained in 
rats fed a 12°, casein diet®® (see also for pertinent previous references). The fasted 
animals lost approx. 35°% of their initial weight and on a fresh weight basis there was 
a decrease in plasma of 7.6°, in protein nitrogen and 21.0% in total a-amino nitrogen 
(taurine not included) by comparison with the controls, the corresponding decreases 
for liver being 5.9 and 45.4% and for muscle 13 and 18%, respectively. Thus, at 
the time the analyses were performed a considerable loss in tissue protein already 
had taken place. The most marked changes in relative distribution of ninhydrin- 
reactive constituents in plasma were increases in valine, leucine and isoleucine 
(determined together), and taurine contents and a decrease in serine. Similar changes 
in these constituents were found in the liver. In addition, the liver showed a relative 
increase 1n aspartic acid and a decrease in glutamine content. In the muscle there 
were reported to be relative decreases in glycine and serine and increases in valine 
and taurine (results for the leucines not being given). Even on the 1st day of the 
fast there was a remarkable decrease in the excretion of all the detectable urinary 
amino acids other than taurine, which increased approx. 1.5-, 7- and 1o-fold over 
the control period on the Ist, 3rd and 5th days of the fast, respectively. The in- 
creased quantities of valine and the leucines, essential amino acids for the rat, in 
the tissues and plasma must have originated in the breakdown of tissue protein 
in the fasted animals. The finding that a general increase in amino acids of tissues 
and blood does not occur suggests that for most of the constituents of tissue proteins 
the rates of degradative metabolism balance the release of these constituents from 
bound form. This does not seem to be the case for valine and the leucines. The marked 
increase in tissue, plasma and urinary taurine indicates that this substance is a 
major end-product of cystine and methionine catabolism in the severely fasted 
animal. 
It was of interest to us to determine whether the amino acid patterns of tissues 
could be altered during relatively short periods of starvation or dehydration during 
References p. 348/349 
