title: Oxidative damage to nuclear DNA in hyperthyroid rat liver: inability of vitamin C to prevent the damage.
abstract: The effects of hyperthyroidism on oxidative DNA damage in liver tissue and modification by vitamin C supplementation were investigated in rats. Animals were rendered hyperthyroid by administration of L-thyroxine (0.4 mg/100 g food) for 25 d. In the plasma samples, T(3), T(4), and thyroid-stimulating hormone (TSH) were measured by radioimmunoassay and ascorbate spectrophotometrically. Oxidative damage to hepatic nuclear DNA was determined by measuring deoxy-guanosine (dG) and 8-oxodG by high-performance liquid chromatography with diode array detector electrochemical detection (HPLC-DAD-ECD). In hyperthyroidism, 8-oxodG/(10(5) dG) levels were significantly higher and plasma vitamin C levels lower than in control rats. The results of this experimental study show that oxidative damage to hepatic nuclear DNA increases in the hyperthyroid state and that vitamin C was not effective in preventing this damage.
authors.affiliation: Department of Biochemistry, Cerrahpaşa Medical Faculty, Istanbul University, Istanbul, Turkey. andican@e-kolay.net
authors.forename: Gülnur
authors.initials: G
authors.lastname: Andican
authors.forename: Remise
authors.initials: R
authors.lastname: Gelişgen
authors.forename: Sabiha
authors.initials: S
authors.lastname: Civelek
authors.forename: Arzu
authors.initials: A
authors.lastname: Seven
authors.forename: Oktay
authors.initials: O
authors.lastname: Seymen
authors.forename: Tuncay
authors.initials: T
authors.lastname: Altuğ
authors.forename: Günnur
authors.initials: G
authors.lastname: Yiğit
authors.forename: Gülden
authors.initials: G
authors.lastname: Burçak
mesh_terms: D000818:Animals; D001205:Ascorbic Acid / Q000494:pharmacology*; D002467:Cell Nucleus / Q000378:metabolism; D004249:DNA Damage; D016166:Free Radical Scavengers / Q000494:pharmacology*; D006980:Hyperthyroidism / Q000188:drug therapy / Q000378:metabolism*; D008099:Liver / Q000166:cytology*; D008297:Male; D018384:Oxidative Stress; D051381:Rats; D017208:Rats, Wistar; D013972:Thyrotropin / Q000097:blood; D013974:Thyroxine / Q000008:administration & dosage / Q000097:blood; D014284:Triiodothyronine / Q000097:blood
chemical_list: D016166:Free Radical Scavengers; D014284:Triiodothyronine; D013972:Thyrotropin; D001205:Ascorbic Acid; D013974:Thyroxine