Radiation and Ascites Tumour Metabolism 221 



cellular reactions other than those already mentioned are 

 proceeding at an irregular rate; e.g. studies in progress of the 

 intermediate carbohydrate metabolism indicate reversible 

 changes in the concentration of various acids (Fig. 3). It 

 appears as if the citric acid consumption is blocked for a short 

 period of time, leading to increased cellular concentration. 

 If so, the blocking is a temporary one, as indicated by the slope 

 of the citric acid curve as well as by occasional analyses which 

 showed almost normal citric acid values some hours later. 

 The changes in acetoacetic acid concentration during these 

 first two hours after irradiation proceed in a similar fashion. 



Simultaneously, the concentration of pyruvic and lactic 

 acid decreases. This may be due in part to a blocking of 

 carbohydrate metabolism. Determinations in the ascites 

 fluid (Fig. 3, ''supernatant") demonstrate that the latter 

 acids are also partly released from the cells into the peritoneal 

 fluid and thence from the entire ascites. Similarly, also, the 

 fluid from irradiated samples is richer in acetoacetic and 

 citric acid (values for the latter are not included in the curve). 

 This leakage renders quantitative determination in the cells 

 rather difficult. Two to four hours after administration of the 

 dose, i^C-labelled lactic acid was found to be incorporated into 

 liver glycogen ; thus, at least part of the lactic acid is stored in 

 the irradiated liver. Increased incorporation of ^*C from 

 labelled glucose into the liver glycogen from ordinary irradi- 

 ated mice has been reported by Lourau (1955). 



As a result of in vivo irradiation the host animals also 

 receive the same dose as the ascites cells. It is of interest to 

 note that neither the intestines nor the liver show any signifi- 

 cant deviation from their normal state with respect to the 

 concentration of acetoacetic, lactic ^nd pyruvic acid during 

 this period of observation. Citric acid determinations were 

 highly variable but, on an average, were slightly increased in 

 the irradiated liver. Changes in the citric acid metabolism 

 have been reported by DuBois, Cochran and Douall (1951), 

 but on animals which had been both fluoroacetate poisoned and 

 irradiated. 



