Effect of X irradiation on adenosine triphosphate and glucose-6-phosphate dehydrogenase in the CaNT mouse tumor

The levels of adenosine triphosphate (ATP) in the transplantable CaNT murine tumor grown in CBA mice at various times following 5, 10, and 15 Gy X rays (100 kVp) were increased within 45 min. Maximal ATP levels occurred at 2.5 h following the 10 Gy dose (3.8 times that of unirradiated controls), returning almost to control levels by 13 h after irradiation. The specific activity of glucose-6-phosphate dehydrogenase (G-6-PDH) after 10 Gy increased about 1.5-fold 1 h after irradiation, returning to control levels by 48 h. It is suggested that the increased ATP following irradiation might play a major role in energy provision when cellular repair processes are able to operate. The increased G-6-PDH activity after irradiation may reflect enhanced metabolism associated with cellular repair mechanisms.