ON CHANGES IN BLOOD VESSEL WALL ELECTROLYTES AND THE ADRENAL CORTEX IN EXPERIMENTAL HYPERTENSION

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Reactivity to pressor substances increases in hypertensive subjects, while it decreases in patients suffering from secondary aldosteronism with edema. It is generally recognized that the contraction of vascular smooth muscle is influenced by the concentration of electrolytes in extracellular and intracellular fluid. Comparisons were made of the electrolyte content of the various tissues in hypertensive rats and those in rats with edema. The adrenal cortices of hypertensive rats caused by the constriction of the unilateral renal artery were studied histologically. Discussions were made of the role that aldosterone plays in renal hypertension of vascular origin. Materials and Methods Male Wister rats were divided into eleven groups and received each treatment as follows. A) control, B) the clipping of the unilateral renal artery, C) administration of triamterene to the hypertensive rats caused by the clipping of the renal artery, D) administration of aldosterone, E) administration of corticosterone, F) administration of aldosterone and corticosterone, G) administration of DOCA, H) administration of DOCA and NaCl, I) administration of aminonucleoside, J) administration of aminonucleoside and triamterene, K) administration of carbon tetrachloride. Blood pressure was determined, and the sodium and potassium content of the aorta, psoas muscle and heart muscle were measured. The adrenal glands of the renal hypertensive rats were removed, stained with hematoxylin-eosin or scarlet-red and submitted to histological examination. Results 1) Blood pressure and sodium and potassium content of the aorta. Blood pressure became elevated one week after the clipping of the renal artery The sodium content of the aorta increased slightly, and the potassium content increased significantly in rats in which hypertension was noted two weeks after the clipping. Both sodium and Potassium content increased significantly ten weeks after the clipping. Blood pressure in renal hypertensive rats failed to fall and the sodium and potassium content remained elevated despite the administration of triamterene. The administration of DOCA and NaCl induced elevation of blood pressure. In this group, both sodium and potassium content of the aorta increased significantly. In other groups to which the steroids of the adrenal cortex were administered, blood pressure was not elevated. In some groups of these normotensive rats, the sodium content of the aorta increased but the potassium content did not increase. The sodium content increased, while the potassium content decreased in rats with nephrosis caused by aminonucleoside and in rats with cirrhosis of the liver caused by carbon tetrachloride.