NEUTRON EFFECTS ON ANIMALS 



69 



SERUM ALKALINE PHOSPHATASE ACTIVITY IN RABBITS 



Since the enzyme activity in normal rabbit serum is much lower than 

 that found in rat serum, a two-hour incubation time was used and the ac- 

 tivity expressed in two-hour units per 100 cc. serum. Several one- and 

 two-hour experiments on individual samples of rabbit serum gave an aver- 

 age value of 0.56 for the ratio between the one- and two-hour units. For 

 a direct comparison of rat and rabbit enzyme levels, therefore, it is neces- 

 sary to multijily the recorded rabbit values by this factor. 



The alkaline enzyme activity was determined in five normal rabbits and 

 re-determined at intervals after exposure of the animals to a single dose of 











25 



5 10 



DAYS AFTER IRRADIATION 



Fig. 1. Serum alkaline phosphatase activity in rabbits before and after irradiation 

 with neutrons. Dose: 56 n in Box Xo. 4. 



neiitron radiation. Three of the animals were given 56 n in Box Xo. 4 

 while the remaining two received the same dose in Box No. 7. Under 

 these conditions the rabbits in Box No. 4 were subjected to radiation of 

 lower intensity but of higher energy (8) than those in Box No. 7. During 

 the period of twenty-seven days following irradiation, no appreciable 

 change in the enzyme level due to exposure in Box No. 4 could be found 

 (Fig. 1). Of the two animals which were irradiated in Box No. 7, one 

 showed an immediate drop in phosphatase activity which amounted to 

 approximately 80 per cent on the tenth day (Fig. 2). The other rabbit 

 underwent a smaller decrease which may be due, in part, to the fact that 

 a less consistent base-line was encountered. In both cases, it is seen that 



