Originally published in Acta Physiol. Scand. 33, 238 (1955). 



87. EFFECT OF IRRADIATION WITH X-RAYS ON THE 

 CATABOLISM OF ETHYLALCOHOL IN THE MOUSE 



G. Hevesy 



From the Institute of Organic Chemistry and Biochemistry, University of 



Stockholm 



Watery suspensions of numerous enzymes can promptly be inactivated,, 

 often by exposure to a restricted dose of ionizing radiation, as first 

 shown by Dale (1942). This type of prompt inactivation of enzymes is 

 not often met in vivo, possibly due to the presence of a great variety 

 of protecting substances and a rapid whipping out of possible changes 

 produced by exposure. Forssberg, for example, (1945) did not succeed 

 in inactivating catalase present in the liver even when he applied as 

 massive doses as 83,000 r. In those experiments, the splitting effect ol" 

 liver slices of controls and exposed animals on hydrogen peroxide was 

 compared and in the study of the effect of irradiation on other enzymes 

 their effect on other suitable substrates. 



Enzyme inactivation can also be studied in the intact animal by admi- 

 nistering a metabolite marked with ^^C and studying the amount of 

 labelled COg exhaled previous to and after exposure. If irradiation reduces 

 the amount of labelled COa exhaled, this does not prove an inactivation 

 of the enzymes involved; viz. the effect of exposure may be due to other 

 reasons than enzyme inactivation and so far the latter took place, it may 

 be difficult to ascertain which of the enzymes involved in the catabolic 

 process w^as influenced. If, however, irradiation does not effect the 

 amount of exhaled CO2 we can conclude that the enzyme system involved 

 in the catabolic process was not influenced by exposure or, more correctly, 

 that a sufficient fraction of enzymes involved remained intact and can 

 thus perform its task at a normal rate. In an earlier communication 

 (1953) we found mice previously exposed to a dose of 1500 r not to 

 catabolise methylalcohol at a lower rate as controls. In the present note 

 the results of a study of the effect of exposure of mice to irradiation with 

 X-rays on the catabolism of ethylalcohol are communicated. 



EXPERIMENTAL 



Albino mice, weighing 12 — 14 gm, were placed each in one of six perforated alu- 

 minium boxes which were fixed in a plexy glass box of 1.5 liter volume. COg-free 

 air passed through the box carrying the exhalatory CO^ which was absorbed hy 



