[The ionic composition of different zones of the rat kidney following magnesium chloride administration]

In 20 min after administration of 0.2 ml/100 g MgCl2 5% solution, Mg contents in the rat kidneys papilla increases while Na and K contents decreases. Administration of 0.2 ml/100 gNaCl 4.4% solution decreases all three ions contents because of enhanced amount of the tissue water. Increase in the Mg content in the kidney tissue is correlated with its content in the blood plasma and not correlated with the changes of its concentration in urine. Increase of the Mg intracellular concentration may be one of the reasons of its reduced reabsorbtion from the tubular fluid.