METHVTLALCOHOL IX THE MOUSE 845 



Bartlett studying the combustion of labelled methanol in the rat 

 recovered 89 per cent of the administered i*C, viz. 05 per cent as COg 

 in expired air, 14 per cent as methanol in the expired air, 3 per cent as 

 methanol in the urine, 3 per cent as formic acid in 1 he urine, and 4 per 

 cent fixed in tissues. In his experiments the rat was given by stomach 

 tube 1 mgm methanol per 1 gm body weight. The complete combustion 

 as measured by radioactive COg formation was found to })roceed inde- 

 pendently of the alcohol concentration at a rate of 25 /igm per gm body 

 weight per hr. In our experiments after intraperitoneal administration 

 of 0.53 mgm of methanol per gm body weight it took 260 min to convert 

 30 per cent of the methanol carbon to COg, the combustion rate being 

 37 ^<gm per gm of body weight per hr. The mouse burns thus per g body 

 weight one and a half times as much methanol as does the rat. 



Very small amounts of methanol, 0.3 //gm per gm of body weight, are 

 not combusted at the same rate as larger amounts. At a rate of 37 jugra 

 per hr 0.3 /igm should be converted into COg in the course of less than 

 a minute, during this interval the descending slope of the curve of Fig. 1 

 representing decreasing specific activity values of the exhaled COg 

 decreases only slightly. In the presence of minute amounts of methanol 

 the rate of intrusion into the tissue is presumably the rate determining 

 reaction. 



While none of our experiments shows a depression of the combustion 

 rate of methanol in the exposed mice, they show that possibly a slight 

 increase in that rate takes place. In numerous cases was an increased 

 rate of biochemical reactions observed in the exposed organism, i. e. 

 by FoRSSBERG, studying the effect of massive doses on the activity of 

 catalase extracted from the liver or sarcoma of the rat, carcinoma of the 

 rabbit or of the coleoptiles of growing barley. Similar results were obtained 

 by us (EuLER and Hevesy, 1942) when investigating the effect of expo- 

 sure of rats on the activity of the catalase of their Jensen-sarcoma. That 

 catalase accelerates the oxidation of methanol was found by Bonnichsen 

 and Theorell (1951) and the slighty increased rate of methanol 

 combustion in the exposed mouse may be due to an enhanced catalytic 

 action of catalase as ascertained by Forssberg and others. 



Summary 



A massive dose of ^^C labelled methanol is converted into COj by the moiise 

 at a rate of 37 fJ-gm per gm of body weight per hour, thus one and a half times more 

 rapidly than by the rat. 



Neither the complete combustion of minute (0.3 jUgm per gm body weight) nor 

 that of large amounts (530 figm per g of body weight) of methanol is depressed 

 by exposure of the mice to an X-ray dose of 1500 r immediately or one day be- 

 fore injecting the animals. 



