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INFLUENCE OF DIETARY OMEGA‐6, ‐3 FATTY ACID SOURCES ON THE INITIATION AND PROMOTION STAGES OF PHOTOCARCINOGENESIS
Author(s) -
Black Homer S.,
Thornby John I.,
Gerguis Janette,
Lenger Wanda
Publication year - 1992
Publication title -
photochemistry and photobiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.818
H-Index - 131
eISSN - 1751-1097
pISSN - 0031-8655
DOI - 10.1111/j.1751-1097.1992.tb02147.x
Subject(s) - corn oil , food science , fatty acid , hairless , chemistry , carcinogen , carcinogenesis , tumor promotion , omega 3 fatty acid , biochemistry , polyunsaturated fatty acid , gene , docosahexaenoic acid
— 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 < 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.