Time-dependent changes in plasma levels of cationic electrolytes produced by hypertonic solutions of low potent...

In order to investigate interrelations of plasma levels of potassium with those of the other electrolytes in case of intraperitoneal administration of hypertonic solution consisting of low potent substance, each of the three hypertonic solutions (2,800 mOsm/L), i.e., 50% glucose, 8.12% sodium chloride, and 13.16% sodium sulphate, was intraperitoneally injected to rats in a dose of 3.5 ml/kg body weight. Blood was sampled from the femoral artery at 0, 5, 10, 20, 30 and 45 min after the administration and at the time-point of death. In all cases of the three administered groups, the plasma levels of magnesium was observed to start increasing from 5 min, and, then, the potassium levels from 10 min. The phosphorus levels did not show a significant increase until 20 min, showing later an abrupt increase until the death. Calcium, on the other hand, did not show any significant change in the plasma level until the death. These findings denote that a high osmotic pressure moves first intracellular water and magnesium ion to the outside of the cell, and , with a time delay, intracellular potassium ion is forced to move slowly to the outside. Finally, intracellular phosphorus seems to be released into the extracellular space as a result of damages by suppression of mitochondrial oxidative phosphorylation and by activation of phospholipase both of which were caused directly or indirectly by a critical osmotic force.