Effect of sodium intake on the brain and the aortic angiotensin-converting enzyme activity in spontaneously hypertensive rat.

Abstract

Effect of sodium intake on angiotensin-converting enzyme activity was studied in five areas of the brain (cerebral cortex, midbrain, striatum, thalamus and hypothalamus) and in subcellular fractions of the aorta (homogenate, mitochondria, microsomes and supernatant) in normotensive, spontaneously hypertensive, and stroke-prone spontaneously hypertensive rats. Angiotensin-converting enzyme activity was significantly higher in the hypothalamic area than in the other areas of the brain in spontaneously hypertensive rat. The enzyme activity of subcellular fractions of the aorta showed an extremely high value in the supernatant in normotensive, spontaneously hypertensive, and stroke-prone spontaneously hypertensive rats. Sodium intake resulted in a marked decrease in the aortic converting enzyme activity, while it did in a significant rise of the enzyme activity in the midbrain area in spontaneously hypertensive rat, and in the midbrain and striatum areas in stroke-prone spontaneously hypertensive rat. It is likely therefore that sodium intake lowers the converting enzyme activity of the aorta. Increased converting enzyme activity of the brain in spontaneously hypertensive rats may play a possible role in hypertension induced by sodium intake.