Effects of fasting on plasma and platelet-free fatty acids and platelet function in healthy males.

10 healthy male volunteers fasted for 72 hours. Their plasma concentration of free fatty acid increased more than two-fold, to 1.8 mmol/l. The number of reversible venous "in vivo" platelet aggregates increased significantly (p less than 0.01); this figure correlated with the concentration of long-chain saturated free fatty acid in plasma (p less than 0.02). The correlation with the amount of long-chain saturated free fatty acid plus oleic acid (18:1) was even better (p less than 0.01). Plasma PF-4 concentration increased, suggesting increased platelet release reaction. In spite of the plasma increase, total platelet FFA concentration was reduced and there was a change in the distribution of platelet free fatty acid which correlated with the degree of aggregation.