The Janus effect: two faces of aldosterone.

Inhibition of the nitric oxide pathway by N(omega)-nitro-l-arginine methyl ester (l-NAME) is well known to produce hypertension and proteinuria, but the mechanisms are less straightforward. Prolonged administration of mineralocorticoids mimics the pathological findings produced by l-NAME. Ikeda and colleagues provide a clue to the mechanism by showing that exposure to l-NAME increases plasma aldosterone 50-fold, and that spironolactone markedly attenuates the renal changes. Thus, chronic l-NAME exposure may turn out to be a model of mineralocorticoid excess.