836 ADVENTURES IN RADIOISOTOPE RESEARCH 



of exhalation of "COg found by us seems, therefore, to be consistent 

 with the fact that adrenaline depresses the resorption rate of the injected 

 NaHiJCOg. 



It is established that O2 consumption and COg formation are increased 

 after adrenaline injection of such amounts as were used in our experi- 

 ments. (7) One may expect, therefore, an increase in the total output of 

 COg in animals given adrenaline. We found only a very slight increase 

 (cf. Table 2B, group 2). Considering that irradiation causes a decrease 

 in the exhalation of CO2 one may assume that adrenaline influences 

 the exhalation of COg in an opposite way to irradiation. In the combined 

 application of adrenaline and X-rays the total output of COg is close 

 to the control value (Table 2B, group 4). This can be understood as a 

 counterbalance of the adrenaline effect by the subsequent irradiation. 



The working hypothesis that the irradiation effect on the exhalation 

 of ^^CJOg is mediated through an interaction of adrenaline, implies that 

 x-rays cause a release of adrenaline in the circulation. However, this 

 is not the case. H. Eui^er kindly determined the adrenaline content 

 of urine of rats irradiated with 1000 r and of controls. The adrenaline 

 excretion was found to be 0.0040—0.0049 /^gm/hr in controls against 

 0.0031 — 0.0037 /^gm/hr X-rayed. Considering that irradiation and admi- 

 nistration of adrenaline both influence the resorption of NaHi*C03 in a 

 similar way it is also spectacular that an additional irradiation following 

 the adrenaline injection completely reverses the decrease in the resorp- 

 tion rate, causing an increase above the normal value (Table 2B, group 3). 

 This point needs further clarification, in particular by administering 

 irradiation before the adrenaline treatment. 



The studies of the effect of administering hormones on the exhalation 

 of '^COg from intraperitoneally injected NaH^COg were warranted on 

 the assumption that the corresponding X-rays effects w^ere mediated via 

 hormonal actions. The results obtained in our experiments do not seem 

 to refute such an assumption with regard to ACTH, although definite 

 proof is difficult to achieve. Apart from the possible mediation of hor- 

 mones in the X-ray effect, our experiments have shown that ACTH and 

 adrenaline per se influence the resorption and exhalation of ^^COg 

 from administered bicarbonate. 



Summary 



i^COg exhalation following intraperitoneal injection of NaH^^COj is markedly 

 decreased after irradiation of mice with 2000 r X-rays. This is due to a depressed 

 resorption rate of the sodium bicarbonate. Because of the rapid exhalation of 

 i*CO^ this effect appears during the first minutes after injection of the isotope, 

 and reverses 5—6 minutes afterwards to give an increased output of ^^COg. 



The effect of subcutaneous injection of ACTH and adrenaline on the same pro- 

 cess was investigated according to the hypothesis that the X-ray effects may be 



