title: 24-hour rhythms in oxidative stress during hepatocarcinogenesis in rats: effect of melatonin or alpha-ketoglutarate.
abstract: To compare the effects of alpha-ketoglutarate (alpha-KG) and melatonin on 24-h rhythmicity of oxidative stress in N-nitrosodiethylamine (NDEA)-injected Wistar male rats, melatonin (5 mg/kg i.p.) or alpha-KG (2 g/kg through an intragastric tube) was given daily for 20 weeks. In blood collected at 6 time points during a 24-h period, serum activity of aspartate transaminase (AST) and alanine transaminase (ALT) and the levels of alpha-fetoprotein (alpha-FP) were measured as markers of liver function. To assess lipid peroxidation and the antioxidant status, plasma levels of thiobarbituric acid reactive substances (TBARS) and of reduced glutathione (GSH) were measured, together with the activity of erythrocyte superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx) and glutathione S-transferase (GST). NDEA augmented mesor and amplitude of rhythms in AST and ALT activity and plasma alpha-FP levels and mesor values of plasma TBARS, while decreasing mesor values of plasma GSH and erythrocyte SOD, CAT, GPx and GST. Acrophases were delayed by NDEA in all cases except for alpha-FP rhythm, which became phase-advanced. Co-administration of melatonin or alpha-KG partially counteracted the effects of NDEA. Melatonin decreased mesor of plasma TBARS and augmented mesor of SOD activity. The results indicate that melatonin and alpha-KG are effective in protecting from NDEA-induced perturbation of 24-h rhythms in oxidative stress. Melatonin augmented antioxidant defense in rats.
authors.affiliation: Department of Biochemistry and Biotechnology, Faculty of Science, Annamalai University, Annamalainagar, Tamil Nadu, India.
authors.forename: Perumal
authors.initials: P
authors.lastname: Subramanian
authors.forename: Kadiyala Babu
authors.initials: KB
authors.lastname: Dakshayani
authors.forename: Seithikurippu R
authors.initials: SR
authors.lastname: Pandi-Perumal
authors.forename: Ilya
authors.initials: I
authors.lastname: Trakht
authors.forename: Daniel P
authors.initials: DP
authors.lastname: Cardinali
mesh_terms: D000410:Alanine Transaminase / Q000097:blood; D000818:Animals; D000975:Antioxidants / Q000494:pharmacology*; D001219:Aspartate Aminotransferases / Q000097:blood; D006528:Carcinoma, Hepatocellular / Q000139:chemically induced / Q000188:drug therapy* / Q000473:pathology; D002374:Catalase / Q000378:metabolism; D002940:Circadian Rhythm / Q000187:drug effects*; D004052:Diethylnitrosamine / Q000633:toxicity; D004912:Erythrocytes / Q000201:enzymology; D005978:Glutathione / Q000378:metabolism; D005979:Glutathione Peroxidase / Q000378:metabolism; D005982:Glutathione Transferase / Q000378:metabolism; D007656:Ketoglutaric Acids / Q000494:pharmacology*; D015227:Lipid Peroxidation / Q000187:drug effects; D008114:Liver Neoplasms, Experimental / Q000139:chemically induced / Q000188:drug therapy* / Q000473:pathology; D008297:Male; D008550:Melatonin / Q000494:pharmacology*; D018384:Oxidative Stress / Q000187:drug effects*; D051381:Rats; D017208:Rats, Wistar; D013482:Superoxide Dismutase / Q000378:metabolism; D017392:Thiobarbituric Acid Reactive Substances / Q000378:metabolism; D000509:alpha-Fetoproteins / Q000378:metabolism
chemical_list: D000975:Antioxidants; D007656:Ketoglutaric Acids; D017392:Thiobarbituric Acid Reactive Substances; D000509:alpha-Fetoproteins; D004052:Diethylnitrosamine; D002374:Catalase; D005979:Glutathione Peroxidase; D013482:Superoxide Dismutase; D005982:Glutathione Transferase; D001219:Aspartate Aminotransferases; D000410:Alanine Transaminase; D005978:Glutathione; D008550:Melatonin