FREE AMINO ACIDS IN BLOOD. IV 403 
The most dramatic changes aside from the total decrease of free amino acids were 
the low levels of taurine in plasma, erythrocytes and leukocytes and the marked 
decrease in the amount of glutathione in the leukocytes. 
Chlorambucil thus produces changes similar to those produced by nitrogen mustard. 
Unlike nitrogen mustard, however, chlorambucil did not appear to affect the level 
of glutamine specifically. It is of considerable interest that the effects on the free 
amino acids of leukocytes noted above are exactly the opposite of those observed 
by McMenamy et al.”? who reported that the free amino acids of leukocytes were 
40% above the pretreatment level on the tenth day of a treatment series where the 
patient was given 6 mg/day of chlorambucil. A similar finding was reported by 
these investigators on the nineteenth day after completion of a three-week course 
of chlorambucil in another patient. The two samples from two different patients 
analyzed by these investigators were compared to other patients without treatment. 
Although a larger dose of drug was given in the studies of MCMENAmy ef al., the 
fact that only a single blood sample from each of two patients was examined prob- 
ably accounts for the discrepancy in results. In our experience each patient must 
be studied both before and after treatment in order to obtain valid and reproducible 
results. 
The effects of nitrogen mustard in rabbits 
Several control studies were carried out as described under METHODS. The results 
with one control animal that was fasted, fed, and fasted again are shown in Figs. 
157-162. The animal was fasted for 23 h (Fig. 157) and then allowed to eat over a 
2h period (57 g of vegetables and 15 g of Purina dog chow were consumed). Blood 
samples were drawn at the end of the feeding period (Fig. 158) and at 3, 8, 20, and 
33 h (Figs. 159-162, respectively). The plasma samples showed minimal variations. 
A fall of total amino acids was evident 20h after feeding, but the fall was not as 
great as that seen in animals given mustard (Figs. 163-168). The free amino acid 
levels of the erythrocyte samples (Figs. 157a-162a) were somewhat variable but no 
definite effect of fasting or feeding was apparent. The variations in the control study 
are quite different from the changes seen in mustard treated animals (Figs. 163a—168a). 
Two control animals were sampled along with mustard treated animals. The only 
significant change in these animals was a small decrease in both alanine and gluta- 
mine in plasma during the studies. 
The results with the control animal that was studied for the effects of multiple 
venipunctures spaced close together are presented in part I. Since the venipuncture 
response does occur, the mustard studies were designed to avoid the free amino acid 
lowering effect of repeated venipunctures by spacing the blood samples at intervals 
of several hours. 
The general nature of the plasma free amino acid response after 1.0 or 2.5 mg/kg 
of nitrogen mustard was a steady decline in the levels of free amino acids that reached 
a low point on the second or third day at about the time the leukocyte count was 
minimal and was then followed by a rapid return to control levels on the fourth day. 
One animal (R-1) that was given 2.5 mg/kg of nitrogen mustard (Figs. 163-168) 
showed first a decrease of some plasma free amino acids 5 h after nitrogen mustard 
and then a rise in plasma amino acids at the end of 24 h. The rise was followed by a 
fall in total free amino acids to a rather low level at 72 h and then a return to slightly 
References p. 447/448 
