Parenteral administration of phospholipase C in the rat. Distribution, elimination, and lethal doses

Infusions of tissue thromboplastin induce intravascular coagulation in animals. Phospholipase C (PLC) (EC 3.1.4.3) from Bacillus cereus has a marked protective effect against such infusions and might be of value in the therapy of certain types of intravascular coagulation. We have therefore studied the toxicity, half-life, and effect on lipolysis of purified PLC in rats, using parenteral administration of 14C-labelled enzyme. Following intravenous injection, the plasma half-life was 5.2-5.4 min, and LD50 was approximately 1.6-1.7 mg/kg. The effect of PLC on lipolysis was moderate. The enzyme does not appear to be bound to any plasma macromolecules, and there was no accumulation of labelled enzyme in tissues other than kidney.