760 ADVENTURES IjST RADIOISOTOPE RESEARCH 



non-irradiated sister rabbit from which the same volume of blood was previously 

 removed. 



The blood was taken from the carotis, heparin added and the blood injected 

 into the jugularis. To avoid the removal of as much as 20 ml from a rabbit weigh- 

 ing about 560 gm only, we carried out the blood transfusion in steps. We removed 

 for example 6 ml replaced this amount by an equal volume of irradiated blood, 

 waited for 2 — 3 minutes to obtain a more or less homogeneous mixing of the 

 blood injected with that originally present in the circulation. This procedure 

 was then twice repeated. 



Labelled phosphate of an activity of about 20 microCuries was administered 

 by subcutaneous injection immediately after the blood transfusion took place 

 and after the lapse of 2 hours the desoxyribo nucleic acid and the free phosphate 

 of the liver, kidney and intestinal mucosa were extracted. A minor part of the 

 purified and ashed fractions was used to a colorimetric P determination Avhile 

 the bulk of the fractions was applied in activity measurements. 



As the rate of renewal of the nucleic acid in the organs of the rabbit is showing 

 appreciable variations, it was necessary to compare the rate of renewal after trans- 

 fusion of irradiated blood with the rate of renewal observed in a sister rabbit of 

 the same age after transfusion of non- irradiated blood of similar volume. The 

 results obtained are seen in Table 1. 



In Table 1 the specific activity of the nucleic acid P is compared both with 

 that of the free organ P and the free plasma P. 



The specific activity of the nucleic acid P of the kidney both compared with 

 the specific activity of the free kidney P and the free plasma P is clearly smaller 

 in rabbits which got irradiated blood injected than in the controls. The difference 

 observed is not insignificant in view that in experiments with rats in which the 

 labelled phosphate was administrated two hours after irradiation with about 

 2000 r, the specific activity of the nucleic acid P extracted from different organs 

 was reduced only to i/g — V3 ^^ ^^^ corresponding value found in controls^^^ 



No definite conclusions can however be drawn from the liver values and clearly 

 no difference is obtained in the case of the intestinal mucosa. 



Summary 



Blood transfusion was carried out from a growing rabbit irradiated with 10,000 r 

 to a non-irradiated sister rabbit. 



Radiophosphorus was administered to the non-irradiated rabbit and after 

 the lapse of 2 hours the specific activity of the desoxyribose nucleic acid phosphoiiis 

 extracted from the kidneys, liver and intestinal mucosa was compared with the 

 free phosphorus extracted from the corresponding organs and from the plasma. 



Control experiments wer carried out after blood transfusion from a non-irradia- 

 ted rabbit to a sister rabbit. 



The transfusion of irradiation blood is followed by a slower formation of label- 

 led desoxyribose nucleic acid in the kidneys. No definite result was obtained in the 

 study of the formation of labelled nucleic acid in the liver and a negative result 

 for the nucleic acid extracted from the intestinal mucosa. 



^1^ L. Ahlstrom, H. Exjleb and G. Hevesy, Ark. Kemi A 19, Nr. 9 (1944). 



