title: Effects of methylmercury exposure on glutathione metabolism, oxidative stress, and chromosomal damage in captive-reared common loon (Gavia immer) chicks.
abstract: We quantified the level of dietary mercury (Hg), delivered as methylmercury chloride (CH3HgCl), associated with negative effects on organ and plasma biochemistries related to glutathione (GSH) metabolism and oxidative stress, and chromosomal damage in captive-reared common loon (Gavia immer) chicks reared from hatch to 105 days. Mercury-associated effects related to oxidative stress and altered glutathione metabolism occurred at 1.2 microg Hg/g and 0.4 microg Hg/g, an ecologically relevant dietary mercury level, but not at 0.08 microg Hg/g. Among the variables that contributed most to dissimilarities in tissue chemistries between control and treatment groups were increased levels of oxidized glutathione (GSSG), GSH peroxidase, and the ratio of GSSG to GSH in brain tissue; increased levels of hepatic GSH; and decreased levels of hepatic glucose-6-phosphate dehydrogenase (G-6-PDH). Our results also suggest that chronic exposure to environmentally relevant dietary Hg levels did not result in statistically significant somatic chromosomal damage in common loon chicks.
authors.affiliation: U.S. Geological Survey, Upper Midwest Environmental Sciences Center, 2630 Fanta Reed Road, La Crosse, WI 54603, USA. kkenow@usgs.gov
authors.forename: Kevin P
authors.initials: KP
authors.lastname: Kenow
authors.forename: David J
authors.initials: DJ
authors.lastname: Hoffman
authors.forename: Randy K
authors.initials: RK
authors.lastname: Hines
authors.forename: Michael W
authors.initials: MW
authors.lastname: Meyer
authors.forename: John W
authors.initials: JW
authors.lastname: Bickham
authors.forename: Cole W
authors.initials: CW
authors.lastname: Matson
authors.forename: Katie R
authors.initials: KR
authors.lastname: Stebbins
authors.forename: Paul
authors.initials: P
authors.lastname: Montagna
authors.forename: Abdulaziz
authors.initials: A
authors.lastname: Elfessi
mesh_terms: D000818:Animals; D001717:Birds / Q000097:blood / Q000254:growth & development* / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D004785:Environmental Pollutants / Q000633:toxicity*; D005506:Food Contamination; D005618:Fresh Water; D005978:Glutathione / Q000378:metabolism; D008628:Mercury / Q000097:blood; D008767:Methylmercury Compounds / Q000633:toxicity*; D009152:Mutagenicity Tests; D018384:Oxidative Stress; D014018:Tissue Distribution; D023382:Toxicity Tests, Acute
chemical_list: D004785:Environmental Pollutants; D008767:Methylmercury Compounds; D008628:Mercury; D005978:Glutathione