Effect of some saturated and unsaturated fatty acids on prostaglandin biosynthesis in washed human blood platelets from (1-c 14)arachidonic acid

The effects of some saturated (lauric, palmitic and stearic) and unsaturated (linoleic, γ-linolenic, α-linolenic and oleic) fatty acids at 0.1, 0.25 and 0.5 mM concentrations on the in vitro metabolization of (1- 14C) arachidonic acid by washed_human blood platelets have been studied. Effects of these fatty acids were studied with intact as well as lysed platelet preparations. With intact platelet preparations it was found that (i) all unsaturated fatty acids enhanced the biosynthesis of TxB 2, PGE 2, PGD 2 and PGF 2α, (ii) unsaturated fatty acids reduced the formation of HHT and HETE with the exception of oleic acid which showed very little effect, (iii) unsaturated fatty acids reduced the formation of MDA, whereas palmitic and stearic acids increased its formation and (iv) all unsaturated fatty acids reduced the synthesis of prostaglandin endoperoxides. These results support our previous observations where effects of fatty acids were examined at higher concentrations (10). At 0.1 mM FA concentration, inconsistent results were obtained. With lysed platelet preparations all cyclooxygenase products were reduced in presence of unsaturated fatty acids, whereas HETE formation was reduced only in presence of linoleic and γ-linolenic acids. Electron micrographs of washed platelet suspensions were obtained with untreated platelet preparations and platelet preparations treated with 0.25 and 0.5 mM linoleic acid concentrations. The results are discussed in the light of a possible soap-like effect of FA salt on platelets.