Platelet fatty acids and prostaglandin turnover during defined linoleic acid intake with formula diets

Platelet fatty acids, platelet aggregation and excretion of main urinary metabolites of prostaglandins were investigated in six healthy females under the influence of liquid formula diets providing a linoleic acid supply of 0 g or 50 g per day for three weeks each. With high intake we found an increase of linoleic acid in platelet lipids from 4.5 to 8.3% on average, while dihomogamma-linolenic acid (20:3 w 6) decreased, and arachidonic acid content of platelet lipids was not changed. ADP induced platelet aggregations decreased under high linoleic acid intake to 84 +/- 6 (mean +/- S.D.) percent of control values. This occurred despite enhanced prostaglandin turnover, measured by determination of main urinary prostaglandin metabolites. It seems, therefore, that the influence of high linoleic acid intake on arachidonic acid metabolism is different in platelets and other body tissue.