ANTICOAGULANT EFFECTS OF WARFARIN IN THE COMMON CARP

The anticoagulant effects of potassium warfarin and the antagonistic e ffects of vitamin K-3 against warfarin were examined in the common car p. Warfarin (1.0 mg/kg/day) with and without vitamin K-3 was orally ad ministered to the common carp for 35 days, and prothrombin time (PT), Russell's viper venom time (RVVT) and the absorbance of the chromogeni c substrate assay (CSA) using S-2337 were measured at intervals of 7 d ays. Prolongation of PT and RVVT, and a decrease in the absorbance in the CSA were observed after the oral administration of warfarin, indic ating that both activities of the extrinsic and common pathways were a ffected. Supplementation with vitamin K-3 (0.1 mg/kg/day) was effectiv e in preventing the prolongation of PT and RVVT, but the decrease in t he absorbance in the CSA was not prevented. These findings suggest the existence of vitamin K-dependent factors involved in both the extrins ic and common pathways.