Phenobarbital < PB ) - in related parameters in duced changes in blood coagulation - pregnant rats , lactating rats and pups

Effects of repeated administration ofphenobarbital (PB) on blood coagulation-related parameters were examined in non-pregnant, pregnant and lactating rats, and also in pups born to PB-treated lactating dams. PB was orally administered at a dose level of 80 mglkglday to pregnant (from gestation day (GD) 13), postpartum (from postpartum day (PPD) 7) and non-pregnant rats (from 13 weeks of age) for 7 days, Blood was collected on GD20 or PPD14 to perform blood coagulation exaxnination. Concurrently, the blood coagulation parameters were examined in the pups. Increases in liver weight andlor hepatic cytochrome P450 content were observed in the PB-treated non-pregnant, pregnant and lactating rats. Activated partial thromboptastin time (APTT) was prolonged and anti-thrombin Il[ (ATIII) concentration was increased in the lactating rats, while there were no changes in prothrombin time (PT) or APTT in the non-pregnant and pregnant rats, Moreover. prolongation of PT and APTT and decreases in factors VII and IX activities were observed in their pups. Thus, prolongation of blood coagulation time was confirmed in both dams and thejr pups fo1towing PB-administration to lactating dams, EfTbcts of vitamin K, (VK,) on PB-induced changes in b]ood coagulation-related parameters of both dams and their pups were examined by co-administration with PB and VK, to lactating dams, PT andAPTT were comparable to the control and PB-induced prolongation of blood coagulation time was improved in the pups while APTT was prolonged in dams, suggesting that VK.. was beneficial to pups but not to dams. Key werds: PB, Vitamin K, APTT, Pregnancy, Lactation, Pup