[Changes in protein metabolism following irradiation. 1. Activity of protease, protease pattern, protein and free amino acids in cytoplams and cell organelles of the rat spleem following 600 R whole-body X-ray irradiation].

The protease activity of cytoplasm and cell organelles of the rat spleen against spleen protein and hemoglobin as a substrate increases during an initial reaction phase of the organism on the first day after 600 R whole body X-irradiation. The alkaline proteases in the cytoplasm and the acid proteases in the cell organelles increase, whereas the protease activity against externally added hemoglobin as substrate decreases below the initial values. The protein, the protease activity and the free amino acids of the cytoplasm and the cell organelles decrease during the disease phase on day 3 and 4 after irradiation. The protein loss of the spleen is therefore not explained by an increased protease activity. Acid proteases appear in the cytoplasm which derive probably from the cell organelles. The protease activity and the free amino acids are increased in the cytoplasm and the cell organelles during the regeneration phase of the organism between day 15 and 18 after irradiation.