Spironolactone, a competitive inhibitor of mineralocorticoid effects on the distal tubule of the kidney, has recently been found to have other metabolic effects. In these studies, spironolactone (200 mg/kg intraperitoneally) for 3 days was found to have a marked protective effect against die hepatotoxic effect of D-galactosamine (275 mg/kg) in rats. Further progress in defining the mechanism of protection from D-galactosamine hepatic necrosis by spironolactone will require assessment of effects of spironolactone on uridine nucleotide metabolism. © 1979 S. Karger AG, Basel.