ARCHIVES OF BIOCHEMISTRY AND BIOPHYSICS Vol. 337, No. 2, January 15, pp. 332–337, 1997 Article No. BB969788 Relationship between Oxidative Stress and Heme Oxygenase Induction by Copper Sulfate 1 Jorge O. Ossola, Marı ´a D. Groppa, and Marı ´a L. Tomaro 2 Departamento de Quı´mica Biolo ´gica, Facultad de Farmacia y Bioquı´mica, Universidad de Buenos Aires, Junı´n 956, Buenos Aires, Argentina Received June 3, 1996, and in revised form October 7, 1996 A number of transition elements and heavy metals The effect of copper sulfate (CuSO 4 ) on both hepatic have been recognized to be powerful inducers of heme oxidative stress and heme oxygenase induction was oxygenase (EC 1.14.99.3) (1, 2), a microsomal enzyme studied. A strong increase in in vivo rat liver chemilu- that catalyzes the degradation of heme to biliverdin (3, minescence was observed 1 h after Cu(II) administra- 4) and, by action of biliverdin reductase, to bilirubin tion. To evaluate liver antioxidant enzymatic defenses, (5) as shown in Eqs. [1] and [2]: superoxide dismutase, catalase, and glutathione per- oxidase activities were determined. Catalase and glu- tathione peroxidase were found to be significantly de- Heme / O 2 / NADPH Heme oxygenase Biliverdin / CO / NADP / [1] creased 5 h after CuSO 4 injection. In contrast, superox- ide dismutase activity was increased. Heme oxygenase Biliverdin / NADPH Biliverdin reductase Bilirubin / NADP / [2] activity appeared 5 h after treatment, reaching a maxi- mum value 18 h after CuSO 4 administration. This in- Cu(II) ion is widely distributed in nature and is an duction was preceded by a decrease in the intrahe- essential element. Copper is a common cofactor for patic GSH pool and an increase in the generation of many enzymes including oxidases and oxygenases (6) thiobarbituric acid reactive substances, both effects and it is present within the protein ceruloplasmin (7). taking place a number of hours before induction of Acute poisoning occurs most frequently from the inges- heme oxygenase. Administration of bilirubin, the end tion of copper sulfate or other copper salts, and hepatic product of heme catabolism in mammals, and a-to- necrosis is characteristic of copper poisoning. Similar copherol, a widely employed antioxidant, completely prevented heme oxygenase induction as well as the to iron, copper acts as a catalyst in the formation of decrease in hepatic GSH and the increase in chemilu- reactive oxygen species and catalyzes peroxidation of minescence when administered 2 h before CuSO 4 treat- membrane lipids (8); it is known to be as effective or ment. Under the same experimental conditions, b-car- even more effective than iron in causing DNA damage otene showed a moderate preventive effect on both (9), protein (10) or peptide modification (11), and oxida- heme oxygenase induction and oxidative stress param- tion of low-density lipoproteins (12). eters. These data obtained with Cu(II) treatment are Oxidized iron and copper salts can similarly generate in agreement with our previous reports suggesting a hydroxyl radicals when added to solutions of hydrogen correlation between heme oxygenase induction and peroxide, although considerably less efficiently than oxidative stress.  1997 Academic Press their reduced metal ions (13). It has been reported that Key Words: heme oxygenase; oxidative stress; copper a copper-catalyzed Haber – Weiss reaction is feasible in sulfate; bilirubin; a-tocopherol; b-carotene; rat liver. vitro, but in vivo copper is unlikely to cause the forma- tion of ‘‘free’’ hydroxyl radicals in the way that has been demonstrated for iron salts (14, 15). Then, whereas the reduction of cupric ions bound to important targets pro- 1 This work was supported by grants from Universidad de Buenos ceeds relatively rapidly by superoxide anion or other Aires (Argentina) and Consejo Nacional de Investigaciones Cientı ´fi- reducing agents, the homolytic cleavage of hydrogen cas y Te ´ cnicas (CONICET) (Argentina). M.L.T. is career investigator peroxide by cuprous ions is very low and a limiting from CONICET. step. The small amount of plasma copper not attached 2 To whom correspondence should be addressed. Fax: 54-1-962- 5341 or 54-1-961-7370. to ceruloplasmin is apparently bound to histidine, 332 0003-9861/97 $25.00 Copyright  1997 by Academic Press All rights of reproduction in any form reserved.