Plasma platelet factor 4 response in rhesus monkeys fed coconut oil

Platelet factor 4 (PF 4), the low molecular weight polypeptide stored in the alpha granule, has been shown to be released from platelets during the process of activation. To examine the effects of known atherogenic food fats on platelet activation, as manifested in circulating PF 4 concentrations, groups of rhesus monkeys were fed diets enriched with varying quantities of different food fats. Plasma PF 4 levels were measured at set intervals during the experimental period. Platelet counts were performed and PF 4 values assayed using the radioligand binding technique. Animals given coconut-oil-enriched diets showed the greatest increase in PF 4 levels; while those fed corn, peanut and soybean-oil-containing rations showed small insignificant fluctuations of plasma PF 4 values. In this study the coconut oil effect on plasma PF 4 values increased with time; diluting the coconut oil with increasing quantities of corn oil led to progressive decreases in these values. These data indicate an increased incidence of platelet activation in animals fed coconut-oil-enriched diets, and suggest that corn oil counteracts this thromboactive effect of coconut oil.