Iron overload upregulates haem oxygenase 1 in the lung more rapidly than in other tissues

Haem oxygenase-l is upregulated by numerous insults, including oxidative st ress, and under such circumstances it is considered to be a protective stra tagem. We have measured the haem oxygenase-l expression in heart, lung and liver tissues of control and iron-overloaded rats. Lung tissue from iron-ov erloaded rats displayed a significant increase in the haem oxygenase-l prot ein but no changes in haem oxygenase-l mRNA, Conversely, heart tissue showe d a significant increase in haem oxygenase-l mRNA but no changes in haem ox ygenase-1 protein. We conclude that during oxidative stress caused by iron overload, lung tissue responds with a rapid upregulation of haem oxygenase- l levels. (C) 1999 Federation of European Biochemical Societies.