The effect of prolil-glycil-proline (PGP) peptide and PGP-rich substances on haemostatic parameters of rat blood

The effect of intravenous and intranasal administration of proline-containing peptide, especially prolil-glycil-proline (PGP), on the haemostatic system of rats was investigated. Tripeptide PGP after single intravenous (0.2, 1.0 and 1.5 mg/kg) or intranasal (0.5 mg/kg) administration increased (P < 0.05) total fibrinolytic and fibrin depolymerizating (FDA) activities, and tissue plasminogen activator levels (t-PA), and decreased the plasmin inhibitors (PI) and activated factor XIII (factor XIIIa) levels in blood plasma. Repeated daily intranasal administration (5 days) of PGP produced a significant increase of anticoagulant and fibrinolytic activities (P < 0.05), and a decrease of platelet aggregation, PI and factor XIIIa levels in blood plasma. Fibrinogen concentrations remained practically unchanged. Chronic peroral administration of gelatin (protein particularly rich of PGP, prolil-glycil, glycil-proline) as a food supplement significantly increased t-PA level (by 120%) at day 10 and FDA (by 290%) at day 14 in blood plasma. We also observed potent suppression of thrombus formation (venous thrombosis model) by intranasal PGP administration. Therefore, PGP and some PGP-rich substances can be qualified as potent anticoagulant and antithrombotic agents. (C) 2000 Lippincott Williams & Wilkins.