Summary
Endotoxin from Salmonella typhosa or enteritidis, Escherichia coli, or Serratia marcescens caused platelet aggregation, release of platelet-bound 14C-serotonin and development of platelet factor 3 activity when shaken at 37 °C with heparinized platelet-rich plasma (10 units/ml) from rabbits. The relative activity in each test differed for each agent. Endotoxoid only released 14C-serotonin. With human platelet-rich plasma, Salmonella typhosa, E. coli or Serratia marcescens endotoxin failed to induce aggregation or platelet factor 3 activity but caused slow release of platelet-bound 14C-serotonin. Earlier studies showed that endotoxemia in man or endotoxoid injection in rabbits was associated with thrombocytopenia without shock or disseminated intravascular coagulation. This effect appears to correlate with release of 14C-serotonin from platelets in vitro.
