[Age-dependence of adenosine deaminase activity in mouse lymphocytes from the spleen and thymus].

The ADA activity was determined in splenocytes and thymocytes of female CBA-mice in dependence on the age of the animals. The investigations were carried out in period of 0 to 120 weeks, the enzyme activities of corresponding cells of animals in the age of 6 weeks served as controls. Whereas the ADA activity of splenocytes did not change during the time of investigations (P = 5%; not significant in analysis of variance), the enzyme activity of thymocytes was diminished significantly in all animals older than 14 weeks. The ratio of the ADA-activities in splenocytes and thymocytes was 1:2 at the beginning of the investigations and 1:1 after 120 weeks.