11-Dehydrocorticosterone in the presence of carbenoxolone is a more potent sodium retainer than corticosterone.

In vivo, corticosterone and 11-dehydrocorticosterone are interconverted in the liver and possibly kidney by 11 beta-hydroxysteroid dehydrogenase. In an effort to evaluate the relevance of this reversible reaction in relation to urinary sodium and potassium excretion, we investigated the effects of 11-dehydrocorticosterone in the presence and absence of carbenoxolone, a potent inhibitor of the oxidative component of 11 beta-hydroxysteroid dehydrogenase, and compared them with the effects of similar doses of corticosterone in carbenoxolone-treated rats. All experiments were performed on adrenalectomized male rats. Here we describe that in carbenoxolone-treated rats 11-dehydrocorticosterone and corticosterone display antinatriuretic activity, although under the conditions of this study 11-dehydrocorticosterone is a more potent sodium retainer than its parent steroid corticosterone. In addition, the antinatriuretic effects of 11-dehydrocorticosterone (like the antinatriuretic effects of corticosterone in carbenoxolone-treated rats) were blocked by the specific antimineralocorticoid RU28318.