Influence of omega-3 and omega-6 fatty acid sources on prostaglandin levels in mice

Studies from this laboratory, employing a hairless mouse model, have indicated that a polyunsaturated fatty acid source rich in omega-3 (n−3) fatty acid (FA) inhibits ultraviolet (UV)-carcinogenic expression, when compared to that of diets containing predominantly n−6 fatty acids. Omega-3 FA is a poor substrate for cyclo-oxygenase, the rate-limiting step in prostaglandin (PG) synthesis—the latter, particularly PGE₂, are known to influence tumor biology. Based upon this rationale, plasma and cutaneous PGE₂ levels were determined from hairless mice fed diets containing either 4% or 12% corn or menhaden oil. After two weeks on the respective diets, plasma PGE₂ levels of corn oil-fed animals were approximately 6-fold greater than those of the menhaden oil-fed groups. A similar response was found in the dermis. Although the relationship to carcinogenic expression is unknown, dietary n−3 FA content can have a pronounced effect upon PGE₂ levels and possesses the potential for influencing other immunomodulators.