ETHYLALCOHOL IN" THE MOUSE 849 



activity of the exhaled COg dechncd already after the lapse of 5 hr to less 

 than 3 per cent of its maximum value observed in an early stage of the experiment . 



In contrast to the controls exposed mice could only be applied once. Before 

 starting the irradiation, food but not water was withdrawn from the mice and 

 from the controls at a corresponding time. In other experiments, food was with- 

 drawn 20 hr before starting the experiment, as the food consumed and resorbed 

 by the exposed mice differs from that of controls; even by pair-feeding this source 

 of error cannot be completely eliminated. The experiments were carried out in a 

 thermostat room kept at a constant temperature of 27.1°. The control mice were 

 kept in the same wooden box in which irradiation took place as were the exposed 

 mice. As the amount of COj exhaled shows a diurnal variation the experiments 

 had to be carried out always at the same hour. 



The specific activity of the exhaled CO2 was determined by comparing the 

 activity of BaCOa samples of identical weight (100 mgra) with that of the ethanol 

 injected after converting it into BaCOa. 



RESULTS 



The result of a typical experiment, in which after 20 hr of fasting 

 6 mice were injected with labelled ethanol, whereupon food was given 

 for about a day and the animals irradiated and injected again the second 

 day after 20 hr of fasting, is seen in Fig. 1. The figures were obtained by 

 plotting the product of the weight of BaCOg obtained by collecting the 

 exhalatoryCOginbaryte, andthe activity of 100 mgm of that compound. 

 As seen from the figure no significant difference is shown by the amount 

 of ^^COg exhaled by the mice previous to and after irradiation. In 4 

 further experiments the total amount of ^^COg exhaled by the exposed 

 animals differed by -f 14,— 8, —7, -f 12 per cent from that given off before 

 irradiation. When injecting the same group of mice 3 times without and 

 the fourth time after exposing them to 1500 r we obtained the following 

 relative figures: 100, 112, 109, 102 for the amount of i^QOa collected. 



ViTALE and assoc. (1953) investigated the rate of alcohol metabolism 

 in rats administered varying doses of alcohol by using ethanol- l-^^C 

 and measuring the ^^COg excreted in the respired air. They found the rate 

 of alcohol oxidation to be directly proportional to the amount adminis- 

 tered up to a maximum of about 2.5 to 3 gm per kilo of body weight. When 

 0.9 gm alcohol/kgm body weight was injected to each rat they found the 

 maximum rate of oxidation of ethanol to amount to 220 mgra/kgm/hr. 

 during the 2nd and 3rd hour after its administration. We found in our 

 experiments with mice a corresponding value of 197 mgm/kgm/hr. This 

 result was obtained with animals fed till the start of the experiment. 

 When mice that had been fasting for 20 hr were investigated, the corre- 

 sponding figure was 149 mgm/kgm/hr. 



That fasting animals catabolise ethanol at an appreciably lower rate 

 than fed-ones Avas already observed by Vitale and assoc. While they 

 recovered 70—90% of the alcohol administered to fed rats, the recovery 



54 Hevesy 



