[Changes in the proteolytic activity and components of the blood kallikrein-kinin system during the growth and metastasis of experimental neoplasms].

Changes in the total blood proteolytic activity, prekallikrein level, serum kallikrein inhibitors and other proteinases were studied during the growth and metastatic spreading of different experimental tumours. It has been established that the dissemination and metastatic spreading of Guérin carcinoma inoculated intratesticularly to rats is accompanied by a decrease in the content of prekallikrein and serum kallikrein inhibitors, which shows the activation of blood kinins. Changes in the total proteolysis and in prekallikrein content in mice with carcinoma 3LL and melanoma B-16 are of two-phase character: at the first stage after tumour inoculation there occurs an increase in the proteolytic activity and in prekallikrein content. At the second stage (14 to 28 days) characterized by the appearance of lung metastases, quite a pronounced and stable inhibition of the total proteolysis and of prekallikrein level was observed together with an increased level of proteinase inhibitors. The data obtained show that disturbances in the reactions of limited proteolysis, in particular shifts of the blood kallikrein-kinin system, play a definite role in the development of the metastatic process.