title: Influence of dietary omega-6, -3 fatty acid sources on the initiation and promotion stages of photocarcinogenesis.
abstract: To determine the segment along the carcinogenic continuum at which dietary lipid exerts its principal effect, six groups of 35 Skh-HR-1 hairless mice were placed on defined isocaloric diets containing either 0.75%, 12% corn oil or 12% menhaden oil as sources of omega-6 or omega-3 fatty acids, respectively. All animals received an 11 week course of UV-radiation from fluorescent sunlamps. Upon termination of UV, diets of some groups were crossed-over to either low fat, high fat, omega-6 or omega-3 fatty acid sources. The first tumor appeared at week 14. Life-table analysis of the tumor incidence curves and Wilcoxon tests of tumor multiplicity provided evidence that high corn oil diets significantly (P less than 0.01) enhance carcinogenic expression; that tumor enhancement by the omega-6 fatty acid source occurs during the post-initiation, or promotion, stage; that replacement with a low corn oil diet after UV-initiation will negate the exacerbating effect of high corn oil; and that an omega-3 fatty acid source inhibits UV-carcinogenesis even at high dietary levels, although not during the post-initiation stage.
authors.affiliation: Veterans Affairs Medical Center, Houston, TX.
authors.forename: H S
authors.initials: HS
authors.lastname: Black
authors.forename: J I
authors.initials: JI
authors.lastname: Thornby
authors.forename: J
authors.initials: J
authors.lastname: Gerguis
authors.forename: W
authors.initials: W
authors.lastname: Lenger
mesh_terms: D000818:Animals; D003314:Corn Oil / Q000008:administration & dosage / Q000633:toxicity; D004042:Dietary Fats, Unsaturated / Q000008:administration & dosage* / Q000009:adverse effects; D015525:Fatty Acids, Omega-3 / Q000008:administration & dosage; D043371:Fatty Acids, Omega-6; D005231:Fatty Acids, Unsaturated / Q000008:administration & dosage / Q000009:adverse effects; D005260:Female; D051379:Mice; D008812:Mice, Hairless; D009381:Neoplasms, Radiation-Induced / Q000209:etiology* / Q000517:prevention & control; D014466:Ultraviolet Rays / Q000009:adverse effects
chemical_list: D004042:Dietary Fats, Unsaturated; D015525:Fatty Acids, Omega-3; D043371:Fatty Acids, Omega-6; D005231:Fatty Acids, Unsaturated; D003314:Corn Oil