146 



N. N. DOEMIN AND V. D. BLOKHINA 



by 30-fold. This resulted in a pronounced qualitative shift of lipid 

 composition in the cytoplasmic organelles. 



Possibly at the beginning of the development of the radiation sickness 

 lipoprotein disintegration was retarded both in the cytoplasmic organ- 

 elles and in the hyaloplasm of the rabbit liver cells; later on this state 

 in the cytoplasmic organelles changes ; and an intensified disintegra- 

 tion begins in them (of the more stable components, especially). They 

 also disi)lay a reduced capacity for binding "free" lipids. In the hyalo- 

 plasm "tirmly bound" lipids proved to be the most stable ones. 



en 

 a 



10 

 8 

 6 

 4 

 2 



/ 



/ 



/ 



0) 



Normal 2 24 



Hours after irradiation 



pjg 3 xiie content (percentage of dry weight) of various lii>iil fractions in the mito- 

 chondria of intestinal nuicosa cells of rabbits under conditions of acute radiation disease; 



curves as in Fig. 1 . 



Similarly, investigations of the intestinal mucosa in rabbit were con- 

 ducted somewhat later under similar conditions of the radiation action ; 

 unlike the previous series these experiments did not deal with prepara- 

 tions of the entire cytoplasm, but with the mitochondria and micro- 

 somes separately. The mitochondria and microsome prejmrations as 

 well as the preparations of the liver cell cytoplasm were produced from 

 homogenates of the intestinal mucosa by differential centrifugation 

 usinff a modified high-speed centrifuges ASL-1 and ASL-2. Additional 

 determinations were made 2 hr following exposure. The results obtained 

 are shown in Figs. 3 to 5 and Table II. 



In total lipid content and that of the separate fractions determined 

 in our experiments, the cells of the intestinal mucosa of the rabbit 

 differ considerably from liver cells. The total lipid content, as per cent 

 dry weight, is significantly less in the intestinal cells. 



It is noteworthy that, although under normal conditions the "free" 



