FREE AMINO ACIDS FOLLOWING HEPATECTOMY 459 
Plasma. Glutamine and all of the other amino acids in plasma increased markedly, 
particularly when insulin was not provided to the eviscerated rat (Fig. 9). 
8 0 
; 9 
| ' 
3 eyo 
Fig. 9. Chromatograms of free amino acids in plasma. Left, normal rat; 200 ul of plasma was 
used. Right, same eviscerated rats as in Fig. 8. Sample consisted of roo yl of plasma. (See footnote 
of fig. 5 for tey to the numbers.) 
COMMENT 
In each tissue there is a pool of free amino acids which provides building material 
for proteins and also is indicative of turnover and degradation of proteins as well 
as interconversions of amino acids. Likewise, the pool of amino acids in plasma 
reflects such changes as they occur in all the tissues. Mechanisms of stabilization of 
these pools of amino acids in the tissues are present, and the liver which is equipped 
to process the conversion of amino acids to urea can be removed without a great 
disturbance in the level of amino acids in blood plasma, skeletal muscle or cardiac 
muscle. Indeed, if adequate insulin was supplied with glucose to either the dehepatized 
dog or eviscerated rat, an increase in the level of amino acids could be prevented 
in these tissues. INGLE, PRESTRUD AND NEZAMIS22 have made a similar observation 
on the plasma of the eviscerated rat. 
Stabilization of the pool of free amino acids in the brain of the dog or the rat 
cannot be produced by insulin or glucose, and removal of the liver results in increased 
content of some free amino acids in the brain. Glutamine increases the most and 
actually spills over into the cerebrospinal fluid. It is not known to what extent the 
increase in brain glutamine is due to increased production of ammonia in the brain 
of the dehepatized animal or accumulation of ammonia which had been formed in 
other tissues. Nor is it known whether production of glutamic acid from glucose 
occurs more rapidly in the brain after removal of the liver and thus provides for 
the neutralization of ammonia. Possibly the glutamine accumulates because further 
metabolism of the substance is blocked by the removal of the liver. 
From the data at hand concerning dehepatized dogs and rats no direct correlation 
References p. 460 
