412 G. ROUSER et al. 
acids seen in dog plasma and tissues by FLock ef al.°3 after total hepatectomy. 
Since dogs survive only 1 day after total hepatectomy, the marked changes seen in 
rabbits injected with phenylhydrazine over a period of several days would not be 
observed. Phenylhydrazine undoubtedly exerts profound effects on extrahepatic 
tissues as well as the liver and hence overall amino acid metabolism is affected to a 
greater extent. Transamination and other metabolic reactions involving carbonyl 
compounds are undoubtedly greatly inhibited by phenylhydrazine and one of the 
major toxic effects of phenylhydrazine may be related to the inability to metabolize 
free amino acids with a resultant toxic effect due to the accumulation of amino acids 
and related metabolites. This may account for the fact that phenylhydrazine pro- 
duces an elevation rather than a depression of blood amino acid levels. This flooding 
of the organism with free amino acids is observed for a short time after the admini- 
stration of nitrogen mustard or dimethylmyleran and is followed by a phase where 
free amino acid levels in plasma and cells are greatly reduced. 
References p. 447/448 
