Neutral cytoplasmatic deoxyribonuclease of the rat liver and spleen in carcinogenesis

: The activity of cytoplasmic neutral DNA in the liver and spleen of albino rats is studied when the tumour process develops after fast neutrons irradiation, when tumour is induced by 3,4-benzpyrene and after sarcoma 45 transplantation. It is shown that an increase in the enzymic activity with a further decrease during the process development is observed for all studied types of carcinogenesis in the pretumour period. Changes in the activity of natural inhibitor and the enzyme form bound with the inhibitor were not found (except for one or another index in the spleen of animals with sarcoma 45). The enzyme activation in the pretumour period is considered as a tumour defence response of the organism aimed at elimination of damages in DNA which arise as a result of direct or indirect action of carcinogen.