152 N. N. DOEMIN AND V. D. BLOKHINA 



the lecithins, cephahns, sphingomyelins and inosine phosphatides in the liver was 

 observed in our laboratoryt already within the first few hours following irradia- 

 tion. It is possible that at least some of the radiation-induced changes of the lipid 

 metabolism in the liver are due to distiu'bances in the acetylcholine metabolisni. 

 Later we established^ that acetylcholine, while inhibiting {in vitro) phospholipid 

 metabolism in normal liver slices, activates it (in certain low concentrations) in 

 slices of liver taken from irradiated animals. 



However, post-irradiation increase of lipid biosynthesis in the liver (as well 

 as in other organs) due to normal mechanisms is also highly probable. 



ARDASHNiKOv: To decipher all these pathways further studies are necessary. 

 What is the statistical reliability of the changes you have observed following 

 irradiation? 



DOEMiN : Since the experiments performed were rather time consuming, the num- 

 ber of replicates was not i^artieularly large. For controls a minimum of 10 assays 

 were performed for every point whereas for the 250st exposure period the nuinber 

 was not less than 4 or 5. Here of course only statistically significant changes were 

 mentioned, and no reference was made to any which were not. 



t Kainova, a. S. (1960). Biocldmia, 25, .'')40. 



X DoEMiN, N. N. and Kaixova, A. S. (1961). Radiobiologiu, 1, 192. 



