LIVER AND AMINO ACID LEVELS IN BLOOD F/ AUS 
is of some interest that in the perfusion of livers taken from alloxan-diabetic rats the 
increases in leucineisoleucine and valine are exaggerated and reach an extreme in 
the perfusion of the liver taken from a ketotic diabetic rat as seen in Fig. 15. In this 
regard, it is of considerable interest that Ivy, SVEC AND FREEMAN, studying changes 
in the blood free amino acids in the experimental alloxan diabetes of the dog, noted 
that only levels of leucine, isoleucine and valine were significantly above their 
normal range!®. Such evidence as we have presented strongly supports the view 

\ | 
RLP 613-6 | RLP 613-1 ie aa plas 
ah. acsdlld 

Fig. 14. Isolated rat liver perfusion (RLP 613). Liver donor, normal male, 18-h fasted Wistar 
(weight, 356 g); liver weight, 7.1 g. Dose of 3.5 mg pL-{1-"C]leucine plus 500 mg glucose added 
to perfusion blood, volume too ml, at outset. Total duration of experiment, 6h. 
that the liver contributes, in a substantial way, to the maintenance of the blood free 
amino acid level under circumstances where amino acids are not forthcoming from 
the diet. 
The introduction of a single dose of 43 mg of L-glutamic acid at the onset of the 
perfusion of a normal liver is associated ultimately not only with the above-mentioned 
changes in leucine-isoleucine and valine but also with the persistence, if not actual 
increase, of some of the non-essential amino acids, particularly alanine (Fig. 16). 
Fig. 17 again shows changes in the free amino acids of the blood incidental to 
perfusion of an isolated liver taken from an 18-h fasted rat with 1.5 mmoles (219 mg) 
of L-glutamine added to the blood at the outset of the perfusion. As was established 
by independent measurements of the disappearance of glutamine from the blood 
References p. 721 
