Heme oxygenase inhibitors transiently increase serum ferritin concentrations without altering other acute-phase reactants in man

Sn protoporphyrin (SnPP) and Sn mesoporphyrin (SnMP), potent inhibitors of heme oxygenase (HO), significantly suppress bilirubin production, lower ser um and biliary bilirubin levels and increase biliary heme output in animals and man. In this study, 20 healthy volunteers, 7 patients with primary bil iary cirrhosis and 4 patients with idiopathic hemochromatosis were treated with SnPP and 4 healthy volunteers with SnMP. In all cases, serum ferritin levels increased substantially but transiently after administration of thes e HO inhibitors. Values returned to baseline within a few days. Infusion of hematin in 4 healthy volunteers did not significantly affect ferritin leve ls. No increases occurred in 7 other acute-phase reactants. The observation that these HO inhibitors transiently increase serum ferritin levels implie s a link between ferritin, iron metabolism and HO activity which may be use fully explored in disorders of iron metabolism.