Feeding of butylated hydroxytoluene to rats caused a rapid decrease in blood coagulation factors II (prothrombin), VII, IX and X.

Male Sprague-Dawley rats were fed a diet containing 1.2% butylated hydroxytoluene (BHT) for 1-7 days, and blood coagulation factors II, VII, VIII, IX and X, and platelet aggregation were measured. The plasma concentrations of factors II, VII, IX and X were significantly reduced in a time-dependent fashion when BHT was administered for 2-7 days and haemorrhages in epididymis were found in rats given BHT for 4-7 days. On the contrary, thrombin-induced and calcium-required aggregation of washed platelets was unchanged throughout the experiment. These results suggest that factors II, VII, IX and X rapidly decrease immediately after the administration of BHT, but hypoaggregability of washed platelets reported previously may be a secondary defect caused by bleeding.