Response of normal BALB/c mouse tissue to p(66 MeV)/Be fast neutron radiation: protection by exogenous ATP.

Exogenous ATP administered by intraperitoneal injection of 700 mg/kg has been used to provide radioprotection of BALB/c mice after a lethal dose of whole body irradiation (6 Gy). This comprised the beam from a neutron therapy facility produced by the reaction p(66 MeV)/Be. Survival of the mice, using 30 days post-irradiation as the endpoint, was increased from 40% to 85% by action of the exogenous ATP. Furthermore, ATP's glucoregulatory effects, which modify basal physiological regulatory processes were studied in the testes and caused significant augmentation in the activities of the glycolytic enzymes hexokinase and lactate dehydrogenase when compared with neutron radiation alone. Finally ATP reduced the activity of testicular acid phosphatase, an indicator of lytic processes in the tissues damaged. These radioprotection actions in BALB/c mice reflect an adaptive defence mechanism to maintain homeostasis in response to the radiation injury.