title: No inhibition of gamma-glutamyl transpeptidase-positive foci by vitamin E with or without phenobarbital.
abstract: The effect of vitamin E on gamma-glutamyl transpeptidase-positive foci, with or without phenobarbital, was investigated. Groups of six female Sprague-Dawley rats were initiated with diethylnitrosamine (15 mg/kg) at 24 hours of age. After weaning, they were fed diets with 10% (wt/wt) fish oil; the diets contained 0, 5,000 or 15,000 ppm vitamin E supplementation with or without phenobarbital (500 ppm) for six months. Phenobarbital significantly increased liver weight and liver weight as a percentage of body weight (p < 0.05), suggesting a liver hypertrophic effect of phenobarbital. Phenobarbital significantly decreased hepatic phospholipid arachidonate, eicosapentaenoate, and docosahexaenoate (p < 0.05); this may indicate that phenobarbital stimulates phospholipase A2 activity and results in the increased release of polyunsaturated fatty acids from phospholipids and the decrease of hepatic phospholipid polyunsaturated-to-saturated fat ratio. In rats fed phenobarbital, hepatic vitamin E content was lower than in rats fed no phenobarbital; this suggests that phenobarbital causes oxidative stress or induces enzymes that metabolize the vitamin. Phenobarbital exposure significantly increased hepatic prostaglandin F2 alpha and glutathione S-transferase activity (p < 0.05). Vitamin E did not influence hepatic gamma-glutamyl transpeptidase-positive foci area and number with or without phenobarbital, and phenobarbital showed a strong promoting action on enzyme-altered hepatic foci.
authors.affiliation: Department of Nutrition, Chung Shan Medical College, Taichung, Taiwan.
authors.forename: C K
authors.initials: CK
authors.lastname: Lii
authors.forename: J J
authors.initials: JJ
authors.lastname: Ko
authors.forename: H W
authors.initials: HW
authors.lastname: Chen
mesh_terms: D000818:Animals; D015237:Dinoprost / Q000096:biosynthesis; D005227:Fatty Acids / Q000378:metabolism; D005260:Female; D005395:Fish Oils / Q000008:administration & dosage; D005982:Glutathione Transferase / Q000378:metabolism; D015227:Lipid Peroxidation / Q000187:drug effects*; D008099:Liver / Q000201:enzymology / Q000378:metabolism* / Q000473:pathology; D008113:Liver Neoplasms / Q000139:chemically induced / Q000378:metabolism / Q000473:pathology; D009929:Organ Size / Q000187:drug effects; D010634:Phenobarbital / Q000008:administration & dosage / Q000494:pharmacology*; D010743:Phospholipids / Q000378:metabolism; D011247:Pregnancy; D051381:Rats; D017207:Rats, Sprague-Dawley; D014810:Vitamin E / Q000008:administration & dosage / Q000378:metabolism / Q000494:pharmacology*; D005723:gamma-Glutamyltransferase / Q000032:analysis*
chemical_list: D005227:Fatty Acids; D005395:Fish Oils; D010743:Phospholipids; D014810:Vitamin E; D015237:Dinoprost; D005723:gamma-Glutamyltransferase; D005982:Glutathione Transferase; D010634:Phenobarbital