Bioactivation of catechol in rat and human bone marrow cells

o-Benzoquinone-glutathione (GSH) conjugate formation and covalent binding of [14C]catechol to protein were utilized as probes of bioactivation of catechol in both rat and human white bone marrow cell systems. Conjugate formation and binding occurred in the absence of exogenous hydrogen peroxide, but were markedly stimulated by its addition. Protein-binding and conjugate formation using rat cells in the presence of exogenous peroxide were increased by the presence of phenol whereas GSH and hydroquinone inhibited binding. Similarly, protein-binding in the absence of exogenous peroxide was inhibited by GSH and exacerbated by phenol. Prostaglandin synthase, the peroxidatic function of which may also utilize hydrogen peroxide as a substrate, appeared on the basis of experiments using arachidonic acid to play only a minor role in bioactivation of catechol in rat bone marrow cells. These results show that peroxide-dependent bioactivation of catechol occurs in rat and human bone marrow cells and that hydroquinone and GSH inhibit whereas phenol stimulates bioactivation.