Effect of vitamin E-deficiency on renin release from renin granules

This study was undertaken to investigate the effects of vitamin E-deficiency on renin release from isolated renin granules. Male Wistar rats were fed either a control or a vitamin E-deficient diet. Renin granules were prepared from the kidney cortex homogenate by a discontinuous sucrose density gradient centrifugation. Renin activity was measured by radioimmunoassay and lipid peroxidation was estimated by means of the thiobarbituric acid test. The intake of vitamin E-deficient diet for 4 weeks resulted in a decrease in alpha-tocopherol content in renin granules, accompanied by an increased level of endogenous lipid peroxides. When the renin granules were incubated at 37 degrees C, the rate of renin release from the granules in vitamin E-deficient group was significantly higher than that in the control group. These results indicate that vitamin E exists in renin granule membranes and functions in maintenance of membrane integrity by blocking the lipid peroxidation.