THE HAEMATOPOIETIC REGENERATION IN WHOLE BODY IRRADIATED RATS 



small and lymphoid, or myeloid structures are no longer present. In the 

 treated rats, the bone marrow is packed with myeloblasts and myelocytes 

 and is even more cellular than the normal marrow. In the spleen the 

 regeneration of lymphoid and myeloid cells is conspicuous ; numerous 

 myeloid foci are to be seen in the red pulp. 



Influence of testosterone propionate and vitamin B^2 ^" ^^^ haematopoietic regeneration 

 The experiments were made on the same scheme as the one used for the 

 assay of growth hormone. The two substances used in this experiment have 

 the same action as growth hormone. They are quite inactive when injected to 

 normal irradiated rats, while they do, on the contrary, stimulate the haema- 

 topoietic regeneration of adrenalectomized animals ; here again, about 

 20 per cent of the individuals survived a lethal whole body irradiation. 





Figure 4. Femoral bone marrow of the rat 10 days after adrenalectomy, 800 r and 

 injection of growth hormone and cortisone acetate (2 • 5 mg daily) . Regeneration of 

 myeloid tissue is conspicuous. {200 X ) . 



SURVEY 



From these experiments, we may conclude that substances stimulating the 

 anabolism of proteins are active in stimulating the haematopoietic regenera- 

 tion of irradiated rats provided they are given to adrenalectomized animals. 

 They are quite inactive in normal rats. The results indicate that, as far 

 as haematopoiesis is concerned, there is an antagonistic effect of adrenal 

 hormones and substances like growth hormone, testosterone propionate and 

 vitamin B^g- It is likely that such an antagonism is related to the action 

 of these substances on the metabolism of proteins. 



In whole body irradiated rats, hypercorticism plays a role in the increased 

 catabolism of proteins which is observed in animals. Betz and Jehotte^^ 

 have shown that a lethal dose of X-rays produces in the rat a quick reduction 

 of food intake, a reduction of nitrogen excretion, together with a negation 



296 



