title: Effect of types and amount of dietary fat during the initiation phase of hepatocarcinogenesis.
abstract: The effects of various levels of corn oil and lard fed during the initiation stage of azoxymethane (AOM)-induced hepatocarcinogenesis were studied in male Fischer 344 rats. The animals were fed diets containing 5%, 13.6%, and 23.5% corn oil or lard two weeks before, during, and until one week after injections of AOM (15 mg/kg body wt s.c.) once weekly for two weeks. One week after AOM treatment, groups of animals fed the 13.6% and 23.5% corn oil or lard diet were transferred to their respective 5% corn oil or lard diet and fed these diets until the termination of the study (34 wk). Immunohistochemical staining of glutathione S-transferase placental form was performed in the liver, and the number of glutathione S-transferase placental form-positive foci was determined. Density, average area, and unit area of foci were significantly inhibited in the animals fed the 13.6% and 23.5% lard diets compared with those fed the 13.6% and 23.5% corn oil diets. These results indicate that the effect of dietary fat during the initiation phase of AOM-induced hepatocarcinogenesis depends on the type of fat and its fatty acid composition. Additionally, the enhancing effect of a corn oil diet in hepatocarcinogenesis is mainly present during the initiation phase of carcinogenesis compared with a lard diet.
authors.affiliation: Department of Pathology, Wayne State University School of Medicine, Detroit, MI 48201, USA. kmrahman@med.wayne.edu
authors.forename: K M
authors.initials: KM
authors.lastname: Rahman
authors.forename: S
authors.initials: S
authors.lastname: Sugie
authors.forename: T
authors.initials: T
authors.lastname: Tanaka
authors.forename: H
authors.initials: H
authors.lastname: Mori
authors.forename: B S
authors.initials: BS
authors.lastname: Reddy
mesh_terms: D000818:Animals; D001397:Azoxymethane; D002273:Carcinogens; D003314:Corn Oil / Q000008:administration & dosage; D004041:Dietary Fats / Q000008:administration & dosage*; D005982:Glutathione Transferase / Q000032:analysis; D007150:Immunohistochemistry; D008099:Liver / Q000201:enzymology; D008113:Liver Neoplasms / Q000139:chemically induced* / Q000201:enzymology; D008297:Male; D051381:Rats; D011916:Rats, Inbred F344
chemical_list: D002273:Carcinogens; D004041:Dietary Fats; D003314:Corn Oil; D005982:Glutathione Transferase; D001397:Azoxymethane; C029310:lard