Activation of factor XII and prekallikrein with cholesterol sulfate

Cholesterol sulfate was found to display a strong ability to trigger the activation of Factor XII and prekallikrein in the presence of HMW kininogen. Other sulfate ester derivatives of testosterone, estrone, pregnenolone and dehydroepiandrosterone and cholesterol tested did not show any effect on the activation of Factor XII and prekallikrein. The activity of cholesterol acetate and sulfodeoxycholic acid was very weak. Cholesterol sulfate markedly shortened the partial thromboplastin time of normal human plasma, but not plasmas deficient in Factor XII, Factor XI and HMW kininogen. Upon prolonged incubation, the partial thromboplastin time of prekallikrein-deficient plasma was also shortened. Moreover, as well as kaolin and sulfatide, cholesterol sulfate shortened the partial thromboplastin time of plasmas from monkey, dog, rat, guinea pig, sheep, cow, hog and horse, but not from duck and chicken. Since cholesterol sulfate is distributed in erythrocytes, various organs and body fluids, it may play an important role in the activation of the intrinsic blood coagulation system.