| Abstract: | The heat shock protein heme oxygenase-1 (HO-1)is regulated by a variety of physiological and pharmacological factors.In skeletal muscle tissue, HO-1 has been shown to be induced only byexercise and electrical stimulation in vivo. Both hemin and sodiumnitroprusside (SNP) are potent inducers of HO-1 in other tissues. Inthis study, we examined the effects of these two agents on HO-1induction in L6.G8 rat skeletal myoblast cells. Hemin and SNP increasedcellular heme oxygenase activity in both a time- andconcentration-dependent manner. Increases in the HO-1 mRNA level andprotein expression accompanied changes in heme oxygenase activity. Theability of SNP to induce HO-1 in L6.G8 cells was reduced bycoincubation with hydroxocobalamin, a known nitric oxide (NO)scavenger, suggesting that NO itself may be involved in HO-1 genestimulation. These results indicate that HO-1 expression is sensitiveto both hemin and SNP in skeletal myoblast cells and may indicate animportant regulatory mechanism of heme catabolism in skeletal muscletissue. |
