Corn oil enhances gamma-glutamyl transpeptidase-positive foci development in the presence of phenobarbital during hepatocarcinogenesis in rats.
We investigated the effects of type of dietary fat and phenobarbital on gamma-glutamyl transpeptidase-positive foci development. Four groups of six female Sprague-Dawley rats were initiated with diethylnitrosamine (15 mg/kg) at 24 hours of age. After weaning, they were fed nutritionally complete semipurified diets containing 15% corn oil or 5% corn oil + 10% fish oil and supplemented with 5,000 ppm vitamin E with or without phenobarbital (500 ppm) for three months. Dietary fish oil significantly increased hepatic phospholipid eicosapentaenoate and docosahexaenoate concentrations and decreased arachidonate concentration compared with 15% corn oil (p < 0.05). Corn oil (15%) significantly increased hepatic prostaglandin F2 alpha concentration compared with 10% fish oil (p < 0.05). Phenobarbital significantly stimulated glutathione S-transferase activity in both dietary fat groups (p < 0.05). In the absence of phenobarbital, type of dietary fat showed no effect on hepatic gamma-glutamyl transpeptidase-positive foci development. However, in the presence of phenobarbital, 15% corn oil significantly enhanced gamma-glutamyl transpeptidase-positive foci development compared with 10% fish oil (p < 0.05). Phenobarbital showed a strong tumor-promoting action in both dietary groups. In conclusion, there was an interaction between type of dietary fat and phenobarbital on gamma-glutamyl transpeptidase-positive foci development during hepatocarcinogenesis in rats.
Chen
H W
HW
Department of Nutrition, Chung Shan Medical College, Taichung, Taiwan, Republic of China.
Ko
J J
JJ
Lii
C K
CK
Ou
C C
CC
Sheen
L Y
LY
D000818:Animals; D002273:Carcinogens; D003314:Corn Oil / Q000008:administration & dosage / Q000494:pharmacology*; D004042:Dietary Fats, Unsaturated / Q000008:administration & dosage / Q000494:pharmacology*; D004052:Diethylnitrosamine; D015237:Dinoprost / Q000378:metabolism; D005227:Fatty Acids / Q000378:metabolism; D005260:Female; D005395:Fish Oils / Q000008:administration & dosage; D005982:Glutathione Transferase / Q000378:metabolism; D008099:Liver / Q000378:metabolism; D008114:Liver Neoplasms, Experimental / Q000201:enzymology* / Q000209:etiology; D010634:Phenobarbital / Q000494:pharmacology*; D010743:Phospholipids / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D014810:Vitamin E / Q000008:administration & dosage; D005723:gamma-Glutamyltransferase / Q000032:analysis*
D002273:Carcinogens; D004042:Dietary Fats, Unsaturated; D005227:Fatty Acids; D005395:Fish Oils; D010743:Phospholipids; D014810:Vitamin E; D004052:Diethylnitrosamine; D003314:Corn Oil; D015237:Dinoprost; D005723:gamma-Glutamyltransferase; D005982:Glutathione Transferase; D010634:Phenobarbital