title: Glutathione protects heavy metal-induced inhibition of hepatic microsomal ethoxyresorufin O-deethylase activity in Dicentrarchus labrax L.
abstract: The in vitro effects of chromium (Cr(VI)), copper (Cu2+), iron (Fe2+), mercury (Hg2+), and zinc (Zn2+) were assessed on liver microsomal ethoxyresorufin O-deethylase (EROD) activity from a sea bass (Dicentrarchus labrax L.) preexposed under laboratory conditions to 2.7 microM beta-naphthoflavone. The reduced glutathione (GSH) protection potential against heavy metal effects was also studied. The heavy metal concentration ranges used for this study were as follows: 10 pM-5 mM Cr(VI), 10 pM-100 microM Cu2+, 10 pM-1 mM Fe2+, 10 pM-10 microM Hg2+, and 10 pM-100 microM Zn2+. Liver microsomal EROD activity was significantly inhibited after in vitro exposure to Cr(VI) (500 microM), Cu2+ (1 microM), Fe2+ (100 microM), Hg2+ (100 pM), and Zn2+ (10 microM). Heavy metals inhibitory effect on liver EROD activity was ordered as follows: Hg2+ > Cu2+ > Zn2+ > Fe2+ > Cr(VI). Protective effects against Hg2+ (1 and 10 microM), Cu2+ (1, 10, and 100 microM), and Zn2+ (10, 50, and 100 microM) were observed in the presence of 0.5 mM GSH by a decrease in liver microsomal EROD activity inhibition. However, 0.5 mM GSH did not protect liver microsomal EROD activity from Cr(VI), and Fe2+-induced inhibition. The effect of metal mixtures (Cu(2+) + Zn(2+), Zn(2+) + Fe(2+), Zn(2+) + Cr(VI), and Cr(VI) + Fe(2+)) (100 microM) on liver microsomal EROD activity was also assessed, revealing a synergistic interaction.
authors.affiliation: Department of Biology, Animal Physiology/Ecotoxicology Sector, University of Aveiro, 3810-193 Aveiro, Portugal.
authors.forename: M
authors.initials: M
authors.lastname: Oliveira
authors.forename: M A
authors.initials: MA
authors.lastname: Santos
authors.forename: M
authors.initials: M
authors.lastname: Pacheco
mesh_terms: D000818:Animals; D001492:Bass / Q000378:metabolism*; D019363:Cytochrome P-450 CYP1A1 / Q000037:antagonists & inhibitors* / Q000096:biosynthesis; D004357:Drug Synergism; D005978:Glutathione / Q000494:pharmacology*; D066298:In Vitro Techniques; D019216:Metals, Heavy / Q000633:toxicity*; D008862:Microsomes, Liver / Q000187:drug effects* / Q000201:enzymology; D011174:Portugal; D020011:Protective Agents / Q000494:pharmacology*; D014874:Water Pollutants, Chemical / Q000633:toxicity*; D019324:beta-Naphthoflavone
chemical_list: D019216:Metals, Heavy; D020011:Protective Agents; D014874:Water Pollutants, Chemical; D019324:beta-Naphthoflavone; D019363:Cytochrome P-450 CYP1A1; D005978:Glutathione