Adenosine Triphosphatase and 5-Nuclcotidase Activity of Hematopoietic Tissues of Irradiated Animals

Abstract

Detailed studies were made of the effect of whole-body X-irradiation on adenosine triphosphatase and 5-nucleotidase activity of spleens and thymuses of rats and mice. Adenosine triphosphatase assays were conducted at frequent intervals during the 1st 14 days after doses of 25 to 400 r. All of these doses produced significant reversible increases in enzyme activity; the amt. of increase and the rate of reversal was dependent upon dose. The increased capacity of hematopoietic tissues of irradiated animals to hydrolyze adenosine triphosphate became evident as early as 3 hrs. after exposure and reached a max. within 72 hrs. After 400 r activity increased to 2-3 times the normal value. A similar relationship between radiation dosage and nucleotidase activity was observed over the range of 100 to 400 r. Lethal doses caused an irreversible increase in adenosine triphosphatase and 5-nucleotidase activity.