[Antithrombotic effect of salivary gland secretion and other preparations from the leech Hirudo medicinalis after intravenous and peroral administration to rats].

Antithrombotic effect of leech salivary gland secretion was maximal after intravenous administration into rats and was slightly decreased in cases of peroral administration. Blood from leech intestinal tract and leech homogenate exhibited less distinct antithrombotic action. Effect of these preparations was maintained after peroral administration. The antithrombotic effect of the leech preparations did not depend on their antithrombic activity caused by hirudin. These leech preparations appear to elongate a period of blood plasma recalcification caused by kallikrein inhibitors as well as apparently due to their capacity to inhibit aggregation of the thrombocytes. Relatively low molecular mass substances, penetrating through pores of cellophan membrane during dialysis, were responsible for the antithrombotic effect of the preparations studied.