In vitro effect of unsaturated fatty acids on the balance between thromboxane A2 and prostacyclin in the blood vascular system.

Unsaturated fatty acids (FAs) (oleic, linoleic, alpha -linolenic, and gamma -linolenic acids) were found to inhibit platelet thromboxane synthetase. This conclusion was based on the following experimental evidence. 1. Reduced formation of TxB2 and increased formation of prostaglandins F2 alpha, E2 and D2 as seen in autoradiography of TLC plate. 2. Inhibition of ADP- and collagen-induced aggregation of PRP samples in the presence of the unsaturated FAs. 3. Reduced formation of TxB2 determined by RIA in PRP samples pretreated with the unsaturated FAs followed by collagen-induced aggregation. 4. Reduced formation of MDA in the presence of the unsaturated FAs. 5. Increased formation of PGI2 (determined as 6-keto-PGF1 alpha), PGE2, PGF2 alpha and PGD2 (redirection effect) in the presence of the unsaturated FAs in a system consisting of washed human platelet preparation and a piece of rat aorta from labelled arachidonate. TxB2 was reduced. 6. Aggregation experiment confirming above.