Altered thiol group status in the heart ornithine decarboxylase inactivated following perfusion with t-butylhydroperoxide.

1. The perfusion for 15 min of isolated rat hearts with 100 microM t-butylhydroperoxide leads to a 75% diminuition of the tissue GSH/GSSG ratio. 2. After t-butylhydroperoxide infusion, the isoproterenol-stimulated heart ODC was strongly inhibited. The addition of 2 mM DTT in the assaying buffer removed the ODC inactivation. 3. The inhibited ODC had an eluition profile similar to active ODC when chromatographed on a Sephacryl S-200 column; moreover, the ODC activity recovered after a thiol affinity chromatography as unbound fraction, was two times increased in the t-butylhydroperoxide perfused hearts in comparison to control. 4. The hearts perfused with 1 mM acetylcysteine after 15 min of perfusion with t-butylhydroperoxide recovered almost completely the initial ODC activity.