Electrolyte loss, the main cause of death from the gastrointestinal syndrome?

Death from the gastrointestinal syndrome after whole body irradiation is usually thought to result from the loss of electrolytes into the intestine subsequent to the depletion of cells from the villi. The data presented cast doubt on the primary role of electrolyte loss in the G.I. syndrome in rodents. The loss of Na⁺ in feces and intestinal tract in less than 10% of the body pool and occurs over the whole postirradiation period. Na⁺ diminishes in blood however only during the few hours immediately prior to death concomitantly with a decrease in plasma volume. Replacement therapy with Na⁺ (as well as antibiotica, plasmaexpander glucose) does not increase survival time although under these conditions sufficient Na⁺ is kept in the body to cause considerable renal excretion. Na⁺ absorption after irradiation is diminished when little Na⁺ is present in the lumen but it can even exceed normal Na⁺ absorption at high concentrations in the lumen. This behavior is explained by the fact that after irradiation active Na⁺ absorption is abolished. No excessive loss of Na⁺ into the lumen is observed in perfused intestinal preparations. It is postulated that not electrolyte loss into the intestine but rather changes in permeability in all organs leading to a state of irreversible shock is responsible for death.