15-hydroxy-11-alpha-9-alpha-(epoxymethano)prosta-5-13-dienoic-acid and Bernard-Soulier-Syndrome

The levels of glycoprotein (GP) Ib and GPV and phospholipase C activity were measured in platelets from three Bernard-Soulier syndrome patients. The patients' platelets had 46%, 46%, and 24% of control levels of GPIb alpha and 43%, trace, and 13% of control levels of GPV as determined by immunoblot analysis. Stimulation by thrombin, trypsin, the thromboxane analogue U46619, and the combination of U46619 and trypsin caused the formation of [32P]phosphatidic acid, an index of phospholipase C activity, in [32P]orthophosphate-prelabeled platelets. With all agonists, however, the formation of [32P]phosphatidic acid was markedly reduced in Bernard-Soulier syndrome platelets compared with control platelets. These data indicated a postreceptor defect in phospholipase C activation in Bernard-Soulier syndrome platelets and confirmed earlier observations of potential proteolytic and nonproteolytic mechanisms of platelet activation.

Topics: 15-Hydroxy-11 alpha,9 alpha-(epoxymethano)prosta-5,13-dienoic Acid; Bernard-Soulier Syndrome; Blood Platelets; Enzyme Activation; Female; Humans; Immunoblotting; Phosphatidic Acids; Phospholipases; Platelet Membrane Glycoproteins; Prostaglandin Endoperoxides, Synthetic; Thrombin; Trypsin