Renal Angiotensinase Activity

Abstract

A rat bioassay technique was employed to determine the localization and properties of the angiotensinase activity present in kidney homogenates of anesthetized rats. The angiotensinase activity per gram of renal cortex was four times greater than renal papilla or medulla. The complete destruction of proximal renal tubular cells by mercuric chloride resulted in losses of cortical angiotensinase activity averaging 40% of control values. The destruction of cells of both the proximal and distal renal tubules by sodium potassium tartrate caused a 90% reduction in angiotensinase activity. Marked reductions in cortical angiotensinase activity were measured in rats injected with meralluride 2 hours previously. The addition of meralluride to in vitro systems of normal rat kidney homogenates caused similar depressions of angiotensinase activity. The presence of reduced glutathione in the reaction media interfered with the ability of meralluride to inhibit angiotensinase and enhanced the activity of this enzyme to greater than normal levels in the absence of the mercurial. Ammonium ion in a concentration of.18 m inhibited angiotensinase activity of renal cortical homogenates by a moderate degree. When both meralluride and ammonium were present in the homogenate system their effects to depress angiotensinase appeared additive.