The modification of sodium excretion after abdominal irradiation

Whole-body counting of radiosodium disappearance in the rat made the evaluation of the disturbance induced in sodium excretion after γ abdominal irradiation at different doses (500, 750, 1000, 1250 and 1500 R) possible. The observed modification was consistent with a dosium excretion loss depending on the dose. Two indices, the relative excretion rate (theta) and the recovery time (Δt), completely defined the radio-induced modification and made feasible the quantitative assessment of its dependence on the dose. The development of the dose-response relationship established for each of these indices led to the conclusions that the reduction in the sodium-excretion rate, which could be related to a defect in sodium intake, is a linear function of the dose, while the time needed to recover the pre-irradiation sodium excretion rate increases exponentially with the dose. (author)