Phenylmercuric acetate and some hemostatic activities of rat platelets.

Fungicide, phenylmercuric acetate (PMA) dose-dependently inhibits in vitro ADP-induced rat platelet primary aggregation. During ex vivo experiments, after oral application of different doses of PMA, the ADP-induced aggregation, clot retraction, bleeding time and clotting time were estimated. Inhibition of platelet activity was found only after a single administration with the high dose of PMA (0.5 LD50). Administration to the rats five times a low dose of PMA (0.2 LD50) and exposure during 5 weeks to the dose of 0.05 LD50 produced hypercoagulation (statistically significant reduction of clotting time) with simultaneous stimulation of platelet activity (stimulation of aggregation, clot retraction and shortening of bleeding time).