The effect of thrombin induced aggregation on human platelet glycosphingolipids

Analyses were made of the glycosphingolipid composition of human platelets before and after treatment with thrombin. Within 10 min after incubation was initiated, there was approximately a two-fold increase in the concentration of hematoside. Concomitantly, the level of lactosylceramide was decreased about three-fold, and there was also a slight diminution in the ceramide levels of these cells. Platelets treated with phenylmethyl-sulfonyl fluoride and thrombin did not exhibit such an effect. These results suggest that lactosylceramide and ceramide are utilized as precursors in the biosynthesis of hematoside and that this conversion accompanies the aggregation of human platelets.