The Effect of Zinc on the Adrenal Gland with Special Reference to the Increasing Effect on Brain Excitability

1. The effect of zinc on the adrena1 gland with special reference to the increasing effect on brain excitability was studied in rats. 2. A single subcutaneous injection of zinc markedly decreased EST. This EST-lowering effect was lost in adrenalectomized rats. 3. Succesive subcutaneous injections of zinc markedly increased adrenal weight in intact rats and the weight of the contralateral adrenal gland inhibited by cortisone after unilateral adrenalectomy. 4. The most remarkable change in histochemical examination produced by zinc administration was a marked acceleration of ATP-ase arid alkaline phosphatase activities in the capillary wall including the reticuloendothelial cells in the adrenal cortex. 5. The histochemical findings of the adrenal medulla were not significantly changed by zinc administration. 6. From the above findings, it is concluded that the EST-lowering effect of systemical1y administered zinc is produced by the stimultibon of the adrenal cortex. Its possiale mechanism is discussed.