S32 ADVENTURES IN KADIOISOTOPE EESEAECH 



Resorption is presumably mediated through hormonal action. This 

 line of thought induced us to investigate the effect of the administration 

 of ACTH and adrenaline on the rate of exhalation of ^^COg following 

 intraperitoneal injection of NaHi^COg. In some of these experiments 

 the administration of the hormones was combined with irradiation. 



Effect of ACTH 



In two sets of experiments the mice were injected subcutaneously 

 on the 2 days preceding the experiment with 0.04 i.u. of ACTH (Acton 

 Prolongatum) to each mouse, and 1 hour before the injection of NaH^^COg 

 with five times that amount. In a third set of experiments 0.008 i.u. 

 of x\CTH was administered for 3 days preceding the experiment and 

 besides 0.04 i.u. 20 minutes before the injection of NaHi*C03. The 

 COg was collected in 2-minute periods as described above. The three 

 •sets of experiments did not differ significantly from each other; possibly 

 the effect of ACTH was slightly greater when the main dose was admi- 

 nistered 20 minutes before the injection of the NaH^^COg. 



As seen in table 2 A (group 1) administration of ACTH accelerates 

 the exhalation of ^^COg markedly. On an average 25% more ^^COg is ex- 

 haled in the first 2 minutes; the difference is statistically significant. 

 The total output of COg is decreased (group 2). As expected, less 

 activity is expelled during the following minutes. That process was 

 not followed up any longer than necessary to demonstrate the principle. 

 In the following groups of experiments only the interval — 2 minutes 

 was studied because the differences are most obvious immediately after 

 the injection of the isotope. 



As shown in figure 1, irradiation alone caused an immediate depression 

 in the exhalation of ^^COg, while ACTH administration increased it. 

 When irradiating the mice after an ACTH administration (the last 

 injection 20 min before the irradiation) it appears that this combined 

 treatment brings about an increase in the output of ^^COg amounting 

 to +32.3% over that obtained from animals being only irradiated 

 (table 2A, group 3). Alternatively, when comparing the effect of the 

 combined treatment with untreated controls no difference in the output 

 •of i^COg could be noticed. Thus, an ACTH treatment previous to the 

 irradiation annuls the X-ray effect. 



Effect of Adrenaline 



The experiments with adrenaline were mainly performed in a similar 

 way. Adrenaline was administered only once, 5—15 minutes before the 

 injection of the labelled bicarbonate. The dose was 2 /^gm adrenaline per 

 mouse, given subcutaneously (Table 2B). Evidently adrenaline acts in 



