Anticoagulant Activity of Equine Follicular Fluid

Summary. The present investigation was undertaken in order to find out why the follicular fluid of the mare does not clot. Although equine follicular fluid was found to contain less fibrinogen than normal blood plasma, there was sufficient present to form a clot after the addition of excess thrombin. The absence of clotting appears to be due to the presence of an active anticoagulant in the follicular fluid. Its properties have been investigated in some detail, and it appears to be very similar to heparin. This anticoagulant may be of considerable physiological significance at the time of ovulation, when it would prevent the ovum becoming trapped in a plasma clot.