Fibre type specificity of haem oxygenase-1 induction in rat skeletal muscle

The expression of the inducible haem oxygenase (HO-1) gene was examined in different skeletal muscles. Rats were treated with haemin and a time course of HO-1 mRNA expression was determined in soleus and extensor digitorum lo ngus (EDL) muscles, Fibre type composition and tissue myoglobin content wer e also measured, We found that HO-1 mRNA expression markedly increased in s oleus (type I fibres) muscle but was only slightly affected in EDL (type II fibres), HO-1 expression directly correlated with both percentage of red f ibres and tissue myoglobin, These data demonstrate that HO-1 gene expressio n follows a fibre type-specific pattern which might indicate an important r ole for this protein in the maintenance of skeletal muscle function. (C) 19 99 Federation of European Biochemical Societies.