REPLACEMENT OF DIETARY SATURATED BY UNSATURATED FATTY-ACIDS - EFFECTSON PLATELET PROTEIN-KINASE-C ACTIVITY, URINARY CONTENT OF 2,3-DINOR-TXB2 AND IN-VITRO PLATELET-AGGREGATION IN HEALTHY MAN

The present study was conducted to compare the effects of oleic (OA) a nd linoleic acids (LA) on platelet function in healthy subjects. After a 4-week period on a diet rich in saturated fatty acids (SAFA), 38 vo lunteers (20 female, 18 male) had a high OA (18.0 en%) diet or a high LA diet (11.5 en%) for four weeks in a controlled manner. A control gr oup of 13 subjects consumed their habitual diet throughout the study. Replacing the SAFA diet by the OA or LA diet did not affect the membra ne-associated activity of platelet protein kinase C (PKC). However, bo th diets tended to increase the cytosolic activity to a comparable ext ent. Both the OA and the LA diets increased urinary excretion of 2,3-d inor-TXB2, as compared to the SAFA diet, whereas the urinary excretion of beta-thromboglobulin remained unchanged. As compared to the initia l SAFA diet, platelet aggregation to collagen increased after both die ts, while ADP induced aggregation showed no diet-induced changes. The results indicate increased platelet activity after both oil diets with no differences between the OA and LA diet and confirm in vitro findin gs that cis-unsaturated fatty acids have a distinct effect on cytosoli c PKC, in particular.