ABSTRACT
It has been known since the 1800s that estrogens modulate vascular tone and vascular reactivity. Over a century ago, MacKenzie (1884) reported that menstrual cycle and pregnancy could cause changes in the degree of hyperemia and vascularity of mucous membranes in women. Sixty years later, Reynolds and Foster (1940) reported that estrogen induced dilation of small vessels in the ear of ovariectomized rabbits. In the 1960s, Ueland and Parer (1966) reported a decrease in systemic vascular resistance during pregnancy. These early studies laid the ground work for a steadily increasing amount of work being done to determine estrogen’s direct effects on vasomotor tone.
