Plasmatic and vascular factors of the hemostatic system in rats receiving an estrogen-progestogen combination

Treatment of rats for 10 estral cycles with an estrogen-progestogen combination giving 100% infertility triggered a vascular response characterized by increased prostacyclin activity in arterial walls and increased systolic blood pressure. In contrast, plasma fibrinolytic activity and physiological coagulation inhibitors as well as vascular fibrinolytic activity were not changed by this treatment. The same rats tended to have shorter occlusion times of an aortic prosthesis, and could represent a useful model to study the blood-vessel-wall interplay during oral contraceptive treatment.