252 P. SOUPART 
acids cystine and cysteine. The increased amount of free and combined taurine 
excreted, as well as that of total sulfate which shows a similar pattern of excretion, 
may well be due in part to increased oxidation of cystine and cysteine. The fact 
that repeated X-irradiation of the patient seems to be unable to produce a sustained 
high taurine excretion may perhaps be due to temporary exhaustion of oxidizable 
sulfur amino acids in the cells. To understand the extra taurine excretion after 
X-irradiation it seems that some factor other than oxidation of amino acids has to be 
taken into account. This was strongly suggested by the second observation to be 
described hereafter. 
As taurine is essentially an intracellular component®’, this amino acid, pre-existing 
Transaminases 
Free spectrophotometric 
Taurine units 
1000 200 
yg fiom On =GPRT 
e@ S.GOT 
100 R 
750 4 Liver area 150 
500 4 
2585) 




-Y~ 0 1 2 3 4 5 6 7 8 
Hours 
Fig. 11. Free taurine plasma levels before and after X-irradiation on liver area of a case of Hodgkin's 
disease, as compared with serum-transaminase activities taken as an index of cell injury. 
or formed under the influence of X-rays, probably finds its way out of the cells to appear 
in increased amount in the plasma. This suggests that, aside from their oxidative 
power, X-rays might also influence the permeability of the cell, leading to the exit 
of normally enclosed components. Accordingly, the free taurine plasma concentration 
as well as glutamic-oxalacetic and glutamic-pyruvic transaminase activities in 
plasma have been determined before and at intervals after the patient (a case of 
Hodgkin’s disease) received 100 r external dose of X-rays on the liver area. As shown 
in Fig. 11, the maximum increase of free taurine plasma concentration coincides 
with a transient but definitely abnormal transaminase-activity level, taken here as 
an index of hepatic and/or Hodgkin cell injury. 
Such a finding, in the author’s opinion, strongly suggests that the oxidative 
effects of X-rays are also accompanied by a specific effect on the permeability of 
the cell, namely on the enzymatic mechanisms which may be invelved to sustain a 
high intracellular content of taurine in normal conditions. Direct evidence, supporting 
this opinion, has been afforded by ScHRAm®! in this department, by total irradiation 
of rats in which taurine was labeled by means of daily injections of 1 mg of [%°S]- 
References p. 261/262 
