Effect of sodium intake on biosynthesis of renin

Tritium labeled leucine was used to investigate the effect of sodium intake on renin biosynthesis. This labeled amino acid was incubated with renal cortical slices from mice which were fed on low, basal and high sodium diets and its incorporation into the renin molecule was investigated. Renin was extracted from the incubated slices and then precipitated with rabbit anti-mouse submaxillary renin serum followed by the addition of goat anti-rabbit IgG serum. The radioactivity incorporated into the renin was 0.07 to 0.22% of that found in the soluble protein. The radioactivity incorporated into renin was increased with incubation time at nearly linear rate and it was decreased by the addition of puromycin or of large amount of unlabeled leucine into the incubation medium. The specific activities of radioactive renin in slices from both mice fed a low sodium and high sodium diet were the same. However, the total radioactivity in renin of the slices from mice fed with low sodium diet was higher than that from mice fed with high sodium diet. This indicates that the production of renin in the mice on low sodium diet was accelerated as compared to that in mice on high sodium diet. The results suggest that change of sodium balance affects the biosynthesis of renin which can lead to changes of renal renin content and its release from the kidney.