LIVER AND AMINO ACID LEVELS IN BLOOD 719 
associated with the essential amino acids previously noted to be oxidized almost 
exclusively by the liver. (c) Remarkable increases are noted not only in ethanol- 
amine but also in phosphoethanolamine. (d) The increase noted in 1-methylhistidine 
and histidine are small and may be referable to the breakdown of hemoglobin from 
lysis of red cells. (e) The striking fofal conversion of arginine, presumably chiefly to 
ornithine and urea, points to the fact that the isolated liver contributes no net 
ey aie x 


£ 
320-5 a 
ail 
ie 
320-0 
Fig. 17. Rat liver perfusion (RLP 320), normal, 18-h fasted Sprague-Dawley, male; liver weight, 
9.5 ; 219 mg L-glutamine (1.5 mmoles) plus 500 mg glucose added to perfusion blood, 177 ml 
at outset. 
arginine to the circulating blood and that free arginine, present in the blood of an 
intact animal, is probably derived from the diet or from non-hepatic tissues. 
ACKNOWLEDGEMENTS 
In the course of the development and use of the isolated liver perfusion technique, 
References p. 721 
