| Popis: |
In rabbits, high doses of sulphinpyrazone (S) result in prolonged inhibition of in vivo collagen-induced thrombocytopenia and platelet MDA production (Buchanan et al., Thromb. Res. 1978, 13., 883). After confirming these results we have shown in guinea pigs that 7 h after oral administration of S there was greater inhibition of AA-induced platelet aggregation than 1 h afterwards, i.e. at the peak plasma S concentration. Thus the concentration of AA needed to induce 50% maximal platelet aggregation at 7 h was raised 2.36 times and 4.73 times after 3 mg/kg and 10 mg/kg of S respectively. When in vivo thrombocytopenia was induced with the Arthus reaction the second phase of inhibition occurred down to a dose of 10 mg/kg p.o. with the first phase seen at higher doses. The inhibitory activity is associated with a high M.W. fraction of plasma proteins (50,000-100,000 Daltons). Phenylbutazone, aspirin andticlopidine did not induce the plasma-borne effect. |
