OXIDATIVE PHOSPHORYLATION IN SOME 

 RADIOSENSITIVE TISSUES AFTER 

 IRRADIATION 



D. W. VAN Bekkum 



Medical Biological Laboratory of the National Defence Research Council TNO, 



Rijsivijk 



Introduction 



Although a considerable number of biochemical studies 

 on irradiated organisms and tissues has been made, informa- 

 tion concerning the primary biochemical lesion in irradiated 

 cells is still lacking. So far it seems that the investigation of 

 radiation effects in radiosensitive tissues has been more profit- 

 able than the study of radioresistant tissues. Unfortunately 

 our knowledge of the biochemistry of the former is limited 

 compared to that of some of the radioresistant tissues e.g. the 

 liver, the muscles and the brain. 



In certain radiosensitive tissues massive cell death occurs 

 within a few hours after irradiation of the animal with a 

 lethal or sublethal dose and these events are bound to be 

 accompanied by a variety of biochemical changes. Therefore 

 the biochemical effects observed in these organs can only be 

 interpreted when the cytological effects are registered as well. 

 Biochemical changes that can be demonstrated before struc- 

 tural damage to the cells becomes apparent are of the greatest 

 interest, because these may be expected to be closely related 

 to or even identical with the primary biochemical lesion. This 

 does not infer however that structural alterations should neces- 

 sarily always be preceded by some enzymatic disturbance. 



The nuclear functions of DNA synthesis and mitosis have 

 been found to be extremely sensitive to ionizing radiation. 

 However, the inhibition of these processes is not limited to 

 radiation and there is no convincing evidence as yet to justify 



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