Changes in 5 alpha- and 5 beta-reductase pathways of aldosterone metabolism by dietary sodium.

The effects of dietary Na+ on 5 alpha- and 5 beta-reductase pathways of aldosterone metabolism in the liver were studied in male rats maintained on low, control, and high Na+ diets. A high Na+ diet caused significant increases in the synthesis of 5 beta-reduced metabolites, primarily 3 alpha, 5 beta-tetrahydroaldosterone; whereas a low Na+ diet stimulated the 5 alpha-reductase pathway causing increases in the synthesis of 5 alpha-dihydroaldosterone and 3 beta 5 alpha-tetrahydroaldosterone, as well as certain polar, hydroxylated metabolites of aldosterone. These studies demonstrate that dietary Na+, a known regulator of aldosterone synthesis, may also regulate enzymes involved in aldosterone metabolism in peripheral tissues.