Toxicity of phospholipase C in rabbits.

Tissue thromboplastin is the most potent physiological trigger of blood coagulation and is probably involved in the pathogenesis of several forms of intravascular coagulation. Phospholipase C from Bacillus cereus is an effective inhibitor of thromboplastin. As part of an investigation into the possible use of phospholipase C as a therapeutic or prophylactic agent in thrombosis and other forms of intravascular coagulation, we have previously studied its effect in rats. We now report on the toxicity in rabbits (along with some data on cats and monkeys). Estimated LD50 for rabbits was about 0.45-0.65 mg/kg (as compared to 1.70 mg/kg for rats). No respiratory or circulatory changes were observed, but phospholipase C caused a significant increase of several plasma enzymes in rabbits.