DIETARY ARACHIDONATE ENHANCES TISSUE ARACHIDONATE LEVELS AND EICOSANOID PRODUCTION IN SYRIAN-HAMSTERS

Eicosanoids are oxidative derivatives of arachidonic acid. When produc ed in excess many of them are proinflammatory agents. This study inves tigates whether dietary arachidonic acid enhances arachidonic acid pho spholipid content of various tissues and whether this enrichment incre ases eicosanoid production. Male Syrian hamsters were divided into fou r groups and fed diets supplemented with ethyl esters of oleic acid, l inoleic acid, arachidonic acid or eicosapentaenoic acid. Differences i n the composition of the phospholipid fatty acids were monitored in li ver, lung, heart, spleen, kidney, testes, macrophages and platelets. I n all tissues analyzed, the phospholipid content of arachidonic acid w as significantly higher in the arachidonic dietary group compared with all other dietary groups (average > 50% higher). In contrast, increas ing dietary linoleic acid by 50% had little effect on altering tissue arachidonic acid levels. Following in vitro stimulation, macrophages a nd platelets from animals maintained on arachidonic acid produced. in general, the highest levels of eicosanoids compared with cells from an imals fed the other diets. Significant differences were observed in pr ostaglandin E2 (macrophages) and thromboxane B2 (platelets) formation when compared with the oleic acid and eicosapentaenoic acid dietary gr oups. The data demonstrate that including low to moderate levels of ar achidonic acid in the diet increases macrophage and platelet arachidon ic acid levels and may augment eicosanoid production.