The effect of estrogen on the vascular endothelium and its possible relation to thrombosis

The effect of estrogen on the permeability of the endothelium of the aorta has been studied in the rat. The endothelium was subjected to different forms of chemical injury, and its permeability to silver ions was estimated in rats in a control group and in rats after estrogen treatment. In rats subjected to estrogen treatment, the degree of silver penetration through the endothelium was significantly higher than in untreated rats. This was interpreted as an increased vulnerability of the endothelium after estrogen treatment. Thrombosis in females using oral contraceptives often has an aberrant localization. These findings lead to a theory that an endothelial factor may be involved in the pathogenesis of this form of thrombosis.