Effect of dietary fat on the fluidity of platelet membranes.

Dietary fat type was reflected in the phospholipid fatty acid composition of the plasma membrane of rabbit platelets and apparently controlled the fluidity of these membranes. Rabbits were maintained for 6 months on diets that varied in stearic and polyunsaturated fatty acids and thus had different potentials for thrombosis. Microviscosities at 37 C, calculated from the arisotropy of fluorescence from the probe 1,6-diphenyl-1,3,5-hexatriene, were 3.5, 3.4, 2.8 and 2.2 poise for platelet membranes isolated from rabbits whose only source of dietary fat was cocoa butter, milkfat, coconut oil, or corn oil, respectively. The relative findings of the membrane isolates were correlated with the polyunsaturated fatty acid contents of the membrane phospholipids.